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Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.

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Perio cons in fpd/ orthodontic straight wire technique Perio cons in fpd/ orthodontic straight wire technique Presentation Transcript

  • PERIODONTAL CONSIDERATIONS FOR FIXED PROSTHODONTICS. INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com
  •  IntroductionIntroduction  AnatomyAnatomy  TerminologiesTerminologies  PathogenesisPathogenesis  ExaminationExamination  Placement of margins of restorationsPlacement of margins of restorations  Tissue dilationTissue dilation  Temporary and provisional crownsTemporary and provisional crowns  EmbrasuresEmbrasures  PonticsPontics  Gingival finish linesGingival finish lines  Summary & conclusionSummary & conclusion  Review of literatureReview of literature  ReferencesReferences www.indiandentalacademy.comwww.indiandentalacademy.com
  • INTRODUCTIONINTRODUCTION Dental restorations and periodontalDental restorations and periodontal health are inseparably inter-related. Thehealth are inseparably inter-related. The adaptation of the margins, the contoursadaptation of the margins, the contours of the restorations, the proximalof the restorations, the proximal relationships and the surface smoothnessrelationships and the surface smoothness have critical biologic impact on thehave critical biologic impact on the gingival and supporting periodontalgingival and supporting periodontal tissues. In addition to esthetics, thetissues. In addition to esthetics, the purpose of fixed prosthesis includes thepurpose of fixed prosthesis includes the improvement of masticatory efficiencyimprovement of masticatory efficiency and prevention of tilting and extrusion ofand prevention of tilting and extrusion of teeth which results further in occlusalteeth which results further in occlusal problems and food impaction.problems and food impaction. www.indiandentalacademy.comwww.indiandentalacademy.com
  • In the fabrication of any fixed prosthesisIn the fabrication of any fixed prosthesis it is imperative that the periodontalit is imperative that the periodontal status of the involved abutment teeth bestatus of the involved abutment teeth be determined. This enables thedetermined. This enables the Prosthodontist to make a reliable andProsthodontist to make a reliable and accurate prognosis for the restoration.accurate prognosis for the restoration. Because periodontal disease is a majorBecause periodontal disease is a major cause of tooth loss in adults, it iscause of tooth loss in adults, it is essential that the practioner be aware ofessential that the practioner be aware of the basic concepts and modes of therapythe basic concepts and modes of therapy available in periodontics to develop anavailable in periodontics to develop an appropriate diagnosis and treatmentappropriate diagnosis and treatment plan.plan. www.indiandentalacademy.comwww.indiandentalacademy.com
  • ANATOMYANATOMY GINGIVA:GINGIVA: The gingiva is the part of theThe gingiva is the part of the oral mucosa that covers the alveolaroral mucosa that covers the alveolar processes of the jaws and surroundingprocesses of the jaws and surrounding the necks of the teeth.the necks of the teeth. The gingiva is divided anatomically intoThe gingiva is divided anatomically into marginal, attached and interdental areas.marginal, attached and interdental areas. TheThe marginal,marginal, or unattached, gingiva isor unattached, gingiva is the terminal edge or border of thethe terminal edge or border of the gingiva surrounding the tooth like agingiva surrounding the tooth like a collar.collar. www.indiandentalacademy.comwww.indiandentalacademy.com
  • Gingival sulcusGingival sulcus: It is the shallow crevice: It is the shallow crevice or space around the tooth bounded byor space around the tooth bounded by the surface of the tooth on one side andthe surface of the tooth on one side and the epithelium lining the free margin ofthe epithelium lining the free margin of the gingiva on the other. It is V shapedthe gingiva on the other. It is V shaped and barely permits the entrance of theand barely permits the entrance of the periodontal probe. In clinically healthyperiodontal probe. In clinically healthy gingiva in humans, a sulcus of somegingiva in humans, a sulcus of some depth can be found. The depth of thisdepth can be found. The depth of this sulcus, as determined in histologicsulcus, as determined in histologic sections, has been reported as 1.8 mm,sections, has been reported as 1.8 mm, with variations of from 0 to 6 mm.with variations of from 0 to 6 mm.www.indiandentalacademy.comwww.indiandentalacademy.com
  • Attached gingiva:Attached gingiva: the attached gingiva isthe attached gingiva is continous with the marginal gingiva. It iscontinous with the marginal gingiva. It is firm, resilient, and tightly bound to thefirm, resilient, and tightly bound to the underlying periosteum of alveolar bone.underlying periosteum of alveolar bone. The facial aspect of the attached gingivaThe facial aspect of the attached gingiva extends to the relatively loose andextends to the relatively loose and movable alveolar mucosa, from which itmovable alveolar mucosa, from which it is demarcated by the mucogingivalis demarcated by the mucogingival junction. The width of the attachedjunction. The width of the attached gingiva is another important clinicalgingiva is another important clinical parameter. It is the distance between theparameter. It is the distance between the mucogingival junction and the projectionmucogingival junction and the projection on the external surface of the bottom ofon the external surface of the bottom of the gingival sulcus or the periodontalthe gingival sulcus or the periodontal pocket.pocket. www.indiandentalacademy.comwww.indiandentalacademy.com
  • Interdental gingivaInterdental gingiva: the interdental: the interdental gingiva occupies the gingival embrasure,gingiva occupies the gingival embrasure, which is the interproximal space bemeathwhich is the interproximal space bemeath the area of tooth contact. The interdentalthe area of tooth contact. The interdental gingiva can be pyramidal or have a colgingiva can be pyramidal or have a col shape.shape. Normal gingiva exhibiting no fluidNormal gingiva exhibiting no fluid exudates or inflammation due to bacterialexudates or inflammation due to bacterial plaque is pink and stippled. In a normalplaque is pink and stippled. In a normal healthy patient there is no visible flow ofhealthy patient there is no visible flow of sulcular fluid, but as disease progressessulcular fluid, but as disease progresses the crevicular flow increases.the crevicular flow increases.www.indiandentalacademy.comwww.indiandentalacademy.com
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  • PERIODONTAL LIGAMENTPERIODONTAL LIGAMENT: The: The periodontal ligament is the connectiveperiodontal ligament is the connective tissue that surrounds the root andtissue that surrounds the root and connects it with the bone. It is continousconnects it with the bone. It is continous with the connective tissue of the gingivawith the connective tissue of the gingiva and communicates with the marrowand communicates with the marrow spaces through vascular channels in thespaces through vascular channels in the bone. The periodontal ligament isbone. The periodontal ligament is composed of collagen fibers arranged incomposed of collagen fibers arranged in bundles that are attached from thebundles that are attached from the cementum of the tooth to the alveolarcementum of the tooth to the alveolar bone of the jaw.bone of the jaw.www.indiandentalacademy.comwww.indiandentalacademy.com
  • It provides attachment and support, nutrition,It provides attachment and support, nutrition, synthesis and resorption, aids in shocksynthesis and resorption, aids in shock absorption, has formative and remodelingabsorption, has formative and remodeling properties, supplies nutrition to cementum,properties, supplies nutrition to cementum, bone and gingiva ( by way of blood vesels andbone and gingiva ( by way of blood vesels and lymphatic drainage), and transmits tactile,lymphatic drainage), and transmits tactile, pressure and pain sensations thru its abundantpressure and pain sensations thru its abundant sensory nerve fibers ( by the trigeminalsensory nerve fibers ( by the trigeminal pathway). It is subjected to constant flux ofpathway). It is subjected to constant flux of change attributable to disease and masticatorychange attributable to disease and masticatory forces. The healthy periodontal ligament inforces. The healthy periodontal ligament in functional occlusion is about 0.25 ±0.1 mmfunctional occlusion is about 0.25 ±0.1 mm wide; it is widest at the margin and apex whilewide; it is widest at the margin and apex while narrowest in the middle one third.narrowest in the middle one third. www.indiandentalacademy.comwww.indiandentalacademy.com
  • The two basic forms of periodontalThe two basic forms of periodontal diseases are gingivitis and periodontitis.diseases are gingivitis and periodontitis. GINGIVITIS:GINGIVITIS: Gingivitis is the mostGingivitis is the most common form of gingival disease, it iscommon form of gingival disease, it is defined as inflammation of the gingiva.defined as inflammation of the gingiva. The two earliest symptoms of gingivalThe two earliest symptoms of gingival inflammation, which precede establishedinflammation, which precede established gingivitis are, (1) increased gingival fluidgingivitis are, (1) increased gingival fluid production rate, and (2) bleeding fromproduction rate, and (2) bleeding from the gingival sulcus on gentle probing.the gingival sulcus on gentle probing. www.indiandentalacademy.comwww.indiandentalacademy.com
  • PERIODONTITIS:PERIODONTITIS: Periodontitis is anPeriodontitis is an inflammatory disease of the gingiva orinflammatory disease of the gingiva or the deeper tissues of the periodontiumthe deeper tissues of the periodontium and is characterized by pocket formationand is characterized by pocket formation and bone destruction. Periodontitis isand bone destruction. Periodontitis is considered a direct extension ofconsidered a direct extension of neglected gingivitis. Periodontitis isneglected gingivitis. Periodontitis is caused by extrinsic irritating factors andcaused by extrinsic irritating factors and is complicated by intrinsic disease,is complicated by intrinsic disease, endocrine disturbances, nutritionalendocrine disturbances, nutritional deficiencies, periodontal traumatism anddeficiencies, periodontal traumatism and other factors.other factors. www.indiandentalacademy.comwww.indiandentalacademy.com
  • When a loss of connective tissueWhen a loss of connective tissue attachment occurs, the lesion transformsattachment occurs, the lesion transforms from gingivitis into periodontitis, afrom gingivitis into periodontitis, a disease that may be characterized bydisease that may be characterized by alternating periods of quiescence andalternating periods of quiescence and exacerbations. The extent to which theexacerbations. The extent to which the lesion progresses before it is treated willlesion progresses before it is treated will determine the amount of bone anddetermine the amount of bone and connective tissue attachment loss thatconnective tissue attachment loss that occurs and will subsequently affect theoccurs and will subsequently affect the prognosis of the tooth with regard toprognosis of the tooth with regard to restorative demands.restorative demands. www.indiandentalacademy.comwww.indiandentalacademy.com
  • ETIOLOGY:ETIOLOGY: Most gingival and periodontal diseases resultMost gingival and periodontal diseases result from microbial plaque, which causefrom microbial plaque, which cause inflammation and its subsequent pathologicinflammation and its subsequent pathologic processes. Other contributors to inflammationprocesses. Other contributors to inflammation however are calculus, acquired pellicle, materialhowever are calculus, acquired pellicle, material alba and food debris.alba and food debris. TERMINOLOGIES:TERMINOLOGIES: MICROBIAL PLAQUE:MICROBIAL PLAQUE: It is a sticky substanceIt is a sticky substance composed of bacteria and their by- products incomposed of bacteria and their by- products in an extra cellular matrix and also containingan extra cellular matrix and also containing substances from the saliva, diet and serum. Itsubstances from the saliva, diet and serum. It is basically a product of the growth of bacterialis basically a product of the growth of bacterial colonies and is the initiating factor in gingivalcolonies and is the initiating factor in gingival and periodontal disease. Left undisturbed it willand periodontal disease. Left undisturbed it will gradually cover the entire tooth surface and cangradually cover the entire tooth surface and can be removed only by mechanical means.be removed only by mechanical means. www.indiandentalacademy.comwww.indiandentalacademy.com
  •  CALCULUS:CALCULUS: Dental calculus is a chalky orDental calculus is a chalky or dark deposit attached to the toothdark deposit attached to the tooth structure. It is essentially microbialstructure. It is essentially microbial plaque that has undergone mineralizationplaque that has undergone mineralization with the passage of time.with the passage of time.  ACQUIRED PELLICLE:ACQUIRED PELLICLE: Pellicle is a thinPellicle is a thin brown or grey film of salivary proteinsbrown or grey film of salivary proteins that develops on teeth after they havethat develops on teeth after they have been cleaned.been cleaned.  MATERIAL ALBA:MATERIAL ALBA: This is a white coatingThis is a white coating composed of micro-organisms, deadcomposed of micro-organisms, dead epithelial cells and leukocyte that isepithelial cells and leukocyte that is loosely adherent to the tooth. It can beloosely adherent to the tooth. It can be removed by water spray or rinsing.removed by water spray or rinsing.www.indiandentalacademy.comwww.indiandentalacademy.com
  •  OCCLUSAL TRAUMATISM:OCCLUSAL TRAUMATISM: OcclusalOcclusal traumatism can be defined as a forcetraumatism can be defined as a force originating by movement of the maxillaryoriginating by movement of the maxillary and mandibular teeth in a way thatand mandibular teeth in a way that creates a pathologic lesion.creates a pathologic lesion.  PRIMARY OCCLUSAL TRAUMA:PRIMARY OCCLUSAL TRAUMA: It is aIt is a pathologic lesion that has been createdpathologic lesion that has been created by a force strong enough to disturb aby a force strong enough to disturb a normal intact periodontium.normal intact periodontium.  SECONDARY OCCLUSAL TRAUMA:SECONDARY OCCLUSAL TRAUMA: It is aIt is a lesion created by a normal function on alesion created by a normal function on a weakened periodontium because ofweakened periodontium because of periodontal disease.periodontal disease.www.indiandentalacademy.comwww.indiandentalacademy.com
  •  PERIODONTAL POCKET:PERIODONTAL POCKET: It is a diseasedIt is a diseased periodontal attachment unit. It is causedperiodontal attachment unit. It is caused by the apical migration of the epithelialby the apical migration of the epithelial attachment with loss of connective tissueattachment with loss of connective tissue attachment and eventually osseousattachment and eventually osseous support. The pocket may also result fromsupport. The pocket may also result from the enlargement of the gingival tissue.the enlargement of the gingival tissue. www.indiandentalacademy.comwww.indiandentalacademy.com
  • PATHOGENESIS:PATHOGENESIS:  INITIAL LESION:INITIAL LESION: The initial lesion is localized inThe initial lesion is localized in the region of the gingival sulcus and is evidentthe region of the gingival sulcus and is evident at approximately 2-4 days of undisturbedat approximately 2-4 days of undisturbed plaque accumulation from a baseline of gingivalplaque accumulation from a baseline of gingival health. The vessels of the gingiva becomehealth. The vessels of the gingiva become enlarged and vasculitis occurs, allowing a fluidenlarged and vasculitis occurs, allowing a fluid exudate of the polymorphonuclear leukocytesexudate of the polymorphonuclear leukocytes to form in the sulcus. Collagen is lostto form in the sulcus. Collagen is lost perivascularly, and the resultant space is filledperivascularly, and the resultant space is filled with proteins and inflammatory cells. The mostwith proteins and inflammatory cells. The most coronal portion of the junctional epitheliumcoronal portion of the junctional epithelium becomes altered. Clinically this stage is notbecomes altered. Clinically this stage is not apparent.apparent. www.indiandentalacademy.comwww.indiandentalacademy.com
  •  EARLY LESION:EARLY LESION: Although there is noAlthough there is no distinct division between the stages ofdistinct division between the stages of lesional formation, the early lesionlesional formation, the early lesion appears within 4-7 days of plaqueappears within 4-7 days of plaque accumulation. This stage of developmentaccumulation. This stage of development exhibits further loss of collagen from theexhibits further loss of collagen from the marginal gingiva. In addition an increasemarginal gingiva. In addition an increase in gingival sulcular fluid flow occurs within gingival sulcular fluid flow occurs with the increase in inflammatory cells andthe increase in inflammatory cells and accumulation of lymphoid cells adjacentaccumulation of lymphoid cells adjacent to the junctional epithelium. The basalto the junctional epithelium. The basal cells of the junctional epithelium begin tocells of the junctional epithelium begin to proliferate and significant alterations areproliferate and significant alterations are seen in the connective tissue fibroblasts.seen in the connective tissue fibroblasts. www.indiandentalacademy.comwww.indiandentalacademy.com
  •  ESTABLISHED LESION:ESTABLISHED LESION: Within 7-21 daysWithin 7-21 days the lesion enters the established stage. Itthe lesion enters the established stage. It is still located in the apical portion of theis still located in the apical portion of the gingival sulcus and the inflammation isgingival sulcus and the inflammation is centered in a relatively small area. Therecentered in a relatively small area. There is continuing loss of connective tissue,is continuing loss of connective tissue, with persistence of the features of thewith persistence of the features of the early lesion. This stage exhibits aearly lesion. This stage exhibits a predominance of plasma cells, thepredominance of plasma cells, the predominance of immunoglobulins in thepredominance of immunoglobulins in the connective tissue, and a proliferation ofconnective tissue, and a proliferation of the junctional epithelium. Pocketthe junctional epithelium. Pocket formation, however, does not necessarilyformation, however, does not necessarily occur.occur. www.indiandentalacademy.comwww.indiandentalacademy.com
  •  ADVANCED LESION:ADVANCED LESION: It is difficult to pinpointIt is difficult to pinpoint the time at which the established lesion ofthe time at which the established lesion of gingivitis results in a loss of connective tissuegingivitis results in a loss of connective tissue attachment to the tooth structure and becomesattachment to the tooth structure and becomes an advanced lesion, or overt periodontitis. Uponan advanced lesion, or overt periodontitis. Upon conversion to the advanced stage the featuresconversion to the advanced stage the features of an established lesion the features of anof an established lesion the features of an advanced lesion persist. The deeper layers ofadvanced lesion persist. The deeper layers of the connective tissues becomes involved withthe connective tissues becomes involved with the ingress of inflammatory cells that enhancethe ingress of inflammatory cells that enhance osteoclastic activity, resulting in a breakdown ofosteoclastic activity, resulting in a breakdown of the alveolar process if at the same time thethe alveolar process if at the same time the tooth is under occlusal trauma this area willtooth is under occlusal trauma this area will change. There can be a concomitant lesion ofchange. There can be a concomitant lesion of the periodontal disease with the occlusalthe periodontal disease with the occlusal traumatic lesion enhancing the loss of bonetraumatic lesion enhancing the loss of bone around the tooth. Periodontal pockets arearound the tooth. Periodontal pockets are formed with increased probing depths.formed with increased probing depths. www.indiandentalacademy.comwww.indiandentalacademy.com
  • EXAMINATION:EXAMINATION: VISUAL EXAMINATION:VISUAL EXAMINATION:  It is important during the examination toIt is important during the examination to evaluate the color, consistency, texture andevaluate the color, consistency, texture and shape of the gingival unit. It is also critical toshape of the gingival unit. It is also critical to recognize the initial stages of a marginal lesion.recognize the initial stages of a marginal lesion. An adequate light source is essential toAn adequate light source is essential to differentiate between normal and diseaseddifferentiate between normal and diseased tissues.tissues.  (Normal gingiva: Colour – coral pink,(Normal gingiva: Colour – coral pink, physiologic melanin pigmentation, scallopedphysiologic melanin pigmentation, scalloped contour on facial or lingual surface, firm andcontour on facial or lingual surface, firm and resilient consistency, stippled attached gingiva,resilient consistency, stippled attached gingiva, normal size, shape and position).normal size, shape and position). www.indiandentalacademy.comwww.indiandentalacademy.com
  • PROBING:PROBING:  The thinnest probe is desired. The probesThe thinnest probe is desired. The probes are calibrated in mm. The Prosthodontistare calibrated in mm. The Prosthodontist should probe six areas around the tooth.should probe six areas around the tooth. Evaluation should include bifurcation andEvaluation should include bifurcation and trifurcation areas on the molars andtrifurcation areas on the molars and maxillary first premolars. During probingmaxillary first premolars. During probing the Prosthodontist should check forthe Prosthodontist should check for bleeding or exudation, these are alsobleeding or exudation, these are also signs of periodontal disease. Clinically thesigns of periodontal disease. Clinically the bleeding of the gingiva during probing isbleeding of the gingiva during probing is the sign of ulceration of sulcularthe sign of ulceration of sulcular epithelium. Specially treated paper toepithelium. Specially treated paper to monitor the intracrevicular fluid is used.monitor the intracrevicular fluid is used. www.indiandentalacademy.comwww.indiandentalacademy.com
  • MOBILITY:MOBILITY:  A classification of 1-3 is used. With 1A classification of 1-3 is used. With 1 representing the early stage of mobilityrepresenting the early stage of mobility and 3 representing a tooth mobile in alland 3 representing a tooth mobile in all direction and depressible in the socket.direction and depressible in the socket. Mobility is an indication of the loss ofMobility is an indication of the loss of tooth attachment to the jaw. This can betooth attachment to the jaw. This can be seen radio graphically as a widenedseen radio graphically as a widened periodontal ligament space caused byperiodontal ligament space caused by occlusal trauma or orthodontic toothocclusal trauma or orthodontic tooth movement. It can also be caused bymovement. It can also be caused by periodontal diseases.periodontal diseases. www.indiandentalacademy.comwww.indiandentalacademy.com
  • RADIOGRAPHS:RADIOGRAPHS:  They provide essential information toThey provide essential information to supplement the clinical examination. The mostsupplement the clinical examination. The most useful type in evaluating the tooth to boneuseful type in evaluating the tooth to bone relationship is the long cone technique. Therelationship is the long cone technique. The areas to be reviewed on the radiographs are:areas to be reviewed on the radiographs are: a). Alveolar crest resorption.a). Alveolar crest resorption. b). Integrity of thickness of the lamina dura.b). Integrity of thickness of the lamina dura. c). Evidence of generalized horizontal bone loss.c). Evidence of generalized horizontal bone loss. d). Evidence of vertical bone loss.d). Evidence of vertical bone loss. e). Widened periodontal ligament space.e). Widened periodontal ligament space. f). Density of trabeculae of both arches.f). Density of trabeculae of both arches. g). Size and shape of the roots compared to theg). Size and shape of the roots compared to the crown to determine crown to root ratio.crown to determine crown to root ratio. www.indiandentalacademy.comwww.indiandentalacademy.com
  • The radiographs can determine the area of root embedded in bone, this is crucial in determining the patient’s prognosis. Often patients with short conical root will display minimal bone loss but maximal mobility, and the prognosis is thus poor. Other patients can loose 50 per cent of the bone but not exhibit mobility, and yet have an encouraging prognosis because they have normal shaped roots. www.indiandentalacademy.comwww.indiandentalacademy.com
  • HABITS:HABITS:  The major habit to consider is bruxism.The major habit to consider is bruxism. Visual examination of wear facets andVisual examination of wear facets and radiographic interpretation of thickenedradiographic interpretation of thickened lamina dura and widened periodontallamina dura and widened periodontal ligament space determines whether aligament space determines whether a patient grinds in his sleep. One conditionpatient grinds in his sleep. One condition that indicates bruxism is a complete archthat indicates bruxism is a complete arch that exhibits mobility despite adequatethat exhibits mobility despite adequate osseous support.osseous support. www.indiandentalacademy.comwww.indiandentalacademy.com
  • PLACEMENT OF MARGINS OF RESTORATIONS:PLACEMENT OF MARGINS OF RESTORATIONS: Except for the risk of subgingival decay andExcept for the risk of subgingival decay and esthetic considerations, it is best to terminateesthetic considerations, it is best to terminate preparations above the gingival margins. Ifpreparations above the gingival margins. If periodontal therapy has been performed andperiodontal therapy has been performed and the gingiva has receded, the preparation shouldthe gingiva has receded, the preparation should end at the cemento-enamel-junction. Even ifend at the cemento-enamel-junction. Even if the tissue does not recede the margin of thethe tissue does not recede the margin of the tooth preparation should be away from the softtooth preparation should be away from the soft tissues. Crown margins when placed subtissues. Crown margins when placed sub gingivally should be located at the base of thegingivally should be located at the base of the gingival sulcus. The gingival fibers can thengingival sulcus. The gingival fibers can then brace the gingiva against the tooth and thebrace the gingiva against the tooth and the margin of the completed restoration.margin of the completed restoration. www.indiandentalacademy.comwww.indiandentalacademy.com
  •  The margins of the preparation are not usuallyThe margins of the preparation are not usually placed at the crest of the marginal gingivaplaced at the crest of the marginal gingiva regardless of how precise the margin of theregardless of how precise the margin of the restoration. Microscopically the margins of therestoration. Microscopically the margins of the restoration are rough and are excellent site torestoration are rough and are excellent site to harbor bacteria. Since the margins of theharbor bacteria. Since the margins of the gingiva rapidly collect plaque, this is the site ofgingiva rapidly collect plaque, this is the site of recurrent decay. If decay does not result, therecurrent decay. If decay does not result, the plaque causes periodontal disease at this mostplaque causes periodontal disease at this most critical area which is not self cleansing.critical area which is not self cleansing.  Conversely, restorations should not be forcedConversely, restorations should not be forced subgingivally into the connective tissue, butsubgingivally into the connective tissue, but placed in the intra crevicular space withoutplaced in the intra crevicular space without violating the biological width. Tearing of theviolating the biological width. Tearing of the epithelial attachment causes it to migrateepithelial attachment causes it to migrate apically and the sulcus to deepen into a pocket.apically and the sulcus to deepen into a pocket. www.indiandentalacademy.comwww.indiandentalacademy.com
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  • SUPRAGINGIVAL MARGINS:SUPRAGINGIVAL MARGINS: Whenever possible margins are preparedWhenever possible margins are prepared supragingivally on the enamel of the clinicalsupragingivally on the enamel of the clinical crown. In addition to the favorable reaction ofcrown. In addition to the favorable reaction of the gingiva, other advantages are gained, athe gingiva, other advantages are gained, a common path of insertion; wider shoulder toothcommon path of insertion; wider shoulder tooth preparations can accommodate an adequatepreparations can accommodate an adequate bulk of porcelain veneering material in thebulk of porcelain veneering material in the cervical area without pulpal injury and metalcervical area without pulpal injury and metal margin finishing techniques are easier. Crownmargin finishing techniques are easier. Crown margins on exposed root surfaces but stillmargins on exposed root surfaces but still supragingival, are necessary for extensive fixedsupragingival, are necessary for extensive fixed partial dentures to secure longer retainers whilepartial dentures to secure longer retainers while encouraging gingival health.encouraging gingival health. www.indiandentalacademy.comwww.indiandentalacademy.com
  • INTRACREVICULAR MARGIN PLACEMENT:INTRACREVICULAR MARGIN PLACEMENT: This term for margin placement impliesThis term for margin placement implies confinement within the gingival crevice. It isconfinement within the gingival crevice. It is preferable to the term subgingival since it’spreferable to the term subgingival since it’s more specific. Despite the advantages ofmore specific. Despite the advantages of supragingival margins there are clinicalsupragingival margins there are clinical situations requiring intra crevicular placementsituations requiring intra crevicular placement even in the periodontally treated teeth. Theyeven in the periodontally treated teeth. They are:are: a). Esthetics.a). Esthetics. b). Caries beyond the gingival crest.b). Caries beyond the gingival crest. c). Cervical erosions.c). Cervical erosions. d). Adequate crown retention in short or brokend). Adequate crown retention in short or broken down clinical crowns.down clinical crowns. e). Elimination of persistent root hypersensitivity.e). Elimination of persistent root hypersensitivity.www.indiandentalacademy.comwww.indiandentalacademy.com
  • INTRACREVICULAR DEPTH:INTRACREVICULAR DEPTH: The average crevice depth according toThe average crevice depth according to GARGIULO et al was between 0.5-1 mmGARGIULO et al was between 0.5-1 mm whether adjacent to enamel or root surfaces.whether adjacent to enamel or root surfaces. Therefore, the ideal intracrevicular position forTherefore, the ideal intracrevicular position for the margins is 0.5 mm beneath the gingivalthe margins is 0.5 mm beneath the gingival crest, especially when the crevice is adjacent tocrest, especially when the crevice is adjacent to root surfaces. While the average crevicularroot surfaces. While the average crevicular depths are nearly identical for enamel or rootdepths are nearly identical for enamel or root surfaces, the average length of the junctionalsurfaces, the average length of the junctional epithelium on the root is between 0.5 and 1epithelium on the root is between 0.5 and 1 mm shorter than that on enamel. Thusmm shorter than that on enamel. Thus overextension of margin placement beneath theoverextension of margin placement beneath the gingiva on root surfaces impinges on gingivalgingiva on root surfaces impinges on gingival connective tissues.connective tissues.www.indiandentalacademy.comwww.indiandentalacademy.com
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  • PULPAL INVOLVEMENT:PULPAL INVOLVEMENT:  In posterior regions, intracrevicular margin placementIn posterior regions, intracrevicular margin placement after the gingival margins have receded isafter the gingival margins have receded is accomplished with minimal pulpal trauma if chamfer oraccomplished with minimal pulpal trauma if chamfer or knife edge margins are prepared.knife edge margins are prepared. WOUND HEALING CONSIDERATIONSWOUND HEALING CONSIDERATIONS  The time elapsed after completion of the periodontalThe time elapsed after completion of the periodontal treatment is crucial when intra crevicular margins aretreatment is crucial when intra crevicular margins are anticipated. Healing of extensive periodontal surgeryanticipated. Healing of extensive periodontal surgery usually requires at least 3 months and often more tousually requires at least 3 months and often more to establish a new biologic width, crevice and stableestablish a new biologic width, crevice and stable position of gingival margin and papilla. Even areasposition of gingival margin and papilla. Even areas treated by scaling, root planning and plaque controltreated by scaling, root planning and plaque control may take more than 1 or 2 months for their gingivalmay take more than 1 or 2 months for their gingival margins to stabilize. Gingival margins after surgerymargins to stabilize. Gingival margins after surgery migrate coronally but recede apically after scaling andmigrate coronally but recede apically after scaling and root planning. Margins prematurely placedroot planning. Margins prematurely placed intracrevicularly in the second situation often becomesintracrevicularly in the second situation often becomes exposed as healing progresses and the result may beexposed as healing progresses and the result may be unesthetic.unesthetic. www.indiandentalacademy.comwww.indiandentalacademy.com
  • AVOID THE GINGIVAL THIRD:AVOID THE GINGIVAL THIRD: The risk of irritation to the gingiva isThe risk of irritation to the gingiva is reduced by restorations that terminatereduced by restorations that terminate coronal to the gingival margin. Whenevercoronal to the gingival margin. Whenever possible inlays, pin ledges, and threepossible inlays, pin ledges, and three quarter crowns should be used asquarter crowns should be used as individual restorations and retainers forindividual restorations and retainers for fixed prosthesis. This does not meanfixed prosthesis. This does not mean substituting other restorations forsubstituting other restorations for purposes that can only be fulfilled by fullpurposes that can only be fulfilled by full crowns.crowns. www.indiandentalacademy.comwww.indiandentalacademy.com
  • ATTACHED GINGIVA:ATTACHED GINGIVA: The gingiva adjacent to intracrevicular crownThe gingiva adjacent to intracrevicular crown margins is an important pre-preparationmargins is an important pre-preparation consideration. The various steps in theconsideration. The various steps in the fabrication of a crown are traumatic to thefabrication of a crown are traumatic to the gingival sulcus and recession is common. Thegingival sulcus and recession is common. The friable mucosa is especially vulnerable duringfriable mucosa is especially vulnerable during instrumentation. Empirical estimates haveinstrumentation. Empirical estimates have suggested 5 mm of keratinized tissuesuggested 5 mm of keratinized tissue composed of 2 mm of free gingiva and 3 mm ofcomposed of 2 mm of free gingiva and 3 mm of attached gingiva for subgingival margins. Thisattached gingiva for subgingival margins. This may be excessive since it is recommended thatmay be excessive since it is recommended that the placing margins no further than 1.5 to 2the placing margins no further than 1.5 to 2 mm beneath the gingival crest, whereas othersmm beneath the gingival crest, whereas others concluded that beyond 0.5 – 1 mm isconcluded that beyond 0.5 – 1 mm is excessive.excessive. www.indiandentalacademy.comwww.indiandentalacademy.com
  • Nevertheless the avoidance of traumaticNevertheless the avoidance of traumatic gingival recessions usually depends on agingival recessions usually depends on a zone of thick keratinized gingiva 4-5 mmzone of thick keratinized gingiva 4-5 mm in width of which 2-3 mm is attached.in width of which 2-3 mm is attached. Despite tissue keratinization if the probeDespite tissue keratinization if the probe is seen thru the free gingival margin, theis seen thru the free gingival margin, the ability to resist trauma is doubtful. Theability to resist trauma is doubtful. The surgical placement of a thickness freesurgical placement of a thickness free autogenous gingiva graft is indicatedautogenous gingiva graft is indicated before the final tooth preparation.before the final tooth preparation. www.indiandentalacademy.comwww.indiandentalacademy.com
  • ATRAUMATIC PREPARATION:ATRAUMATIC PREPARATION: The free and attached gingiva resistsThe free and attached gingiva resists insults more effectively if the connectiveinsults more effectively if the connective tissue fibers are intact and not inflamed.tissue fibers are intact and not inflamed. DRAGOO and WILLIALS haveDRAGOO and WILLIALS have demonstrated that the placement ofdemonstrated that the placement of retraction cord into the sulcus beforeretraction cord into the sulcus before preparation protects the epithelium frompreparation protects the epithelium from damage.damage. www.indiandentalacademy.comwww.indiandentalacademy.com
  • GINGIVAL RETRACTION FOR TAKINGGINGIVAL RETRACTION FOR TAKING IMPRESSIONS:IMPRESSIONS: When taking plastic impressions it is oftenWhen taking plastic impressions it is often necessary to retract the gingiva to gainnecessary to retract the gingiva to gain access to the gingival margin of theaccess to the gingival margin of the preparation. There are methods forpreparation. There are methods for retracting the healthy gingiva. They areretracting the healthy gingiva. They are not for the removal, displacement, ornot for the removal, displacement, or shrinkage of inflamed swollen gingivalshrinkage of inflamed swollen gingival tissue. The gingiva must be healthy andtissue. The gingiva must be healthy and its position on the tooth establishedits position on the tooth established before the impression is made. There arebefore the impression is made. There are several terms for the process of exposingseveral terms for the process of exposing margins when making impressions ofmargins when making impressions of prepared teeth.prepared teeth. www.indiandentalacademy.comwww.indiandentalacademy.com
  • Tissue dilation is synonymous with tissueTissue dilation is synonymous with tissue retraction or displacement. Tissueretraction or displacement. Tissue management is the key factor inmanagement is the key factor in accurately duplicating subgingivalaccurately duplicating subgingival margins.margins. In performing tissue dilation, theIn performing tissue dilation, the Prosthodontist must recognize theProsthodontist must recognize the importance of using a regimentedimportance of using a regimented approach from diagnosis to cementationapproach from diagnosis to cementation of the restorations. The gingival tissueof the restorations. The gingival tissue should be healthy before restorativeshould be healthy before restorative procedures begin, particularly withprocedures begin, particularly with complete restorations that require acomplete restorations that require a margin below the crest of the gingiva.margin below the crest of the gingiva. www.indiandentalacademy.comwww.indiandentalacademy.com
  • TISSUE HEALTH:TISSUE HEALTH: The rationale for tissue dilation does notThe rationale for tissue dilation does not originate with exposing gingival margins,originate with exposing gingival margins, since the health of the gingival tissues issince the health of the gingival tissues is crucial for success. Acceptable healthycrucial for success. Acceptable healthy gingival tissue is essential, as inflamed,gingival tissue is essential, as inflamed, redundant tissue is a liability to tissueredundant tissue is a liability to tissue dilation. Also, after impressions are madedilation. Also, after impressions are made the tissue should be supported bythe tissue should be supported by appropriate treatment restorations on theappropriate treatment restorations on the newly prepared teeth. Tissue shrinkagenewly prepared teeth. Tissue shrinkage may occur after gingival marginmay occur after gingival margin placement or from irritation caused byplacement or from irritation caused by treatment restorations.treatment restorations. www.indiandentalacademy.comwww.indiandentalacademy.com
  • In addition, patients receiving restorativeIn addition, patients receiving restorative procedures should be introduced to aprocedures should be introduced to a regimental oral hygiene program. Ifregimental oral hygiene program. If gingival surgery was done, tissue shouldgingival surgery was done, tissue should be mature before tooth preparation andbe mature before tooth preparation and tissue dilation. The healing of the gingivaltissue dilation. The healing of the gingival tissues after periodontal surgery varies,tissues after periodontal surgery varies, but a minimum of 3 to 5 weeks isbut a minimum of 3 to 5 weeks is recommended before preparation andrecommended before preparation and tissue dilation.tissue dilation. www.indiandentalacademy.comwww.indiandentalacademy.com
  • TISSUE DILATION:TISSUE DILATION: ClassificationClassification The classification for tissue dilation is asThe classification for tissue dilation is as follows:follows: 1.1. Mechanical -Mechanical - the tissue is displaced orthe tissue is displaced or dilated strictly by mechanical methods.dilated strictly by mechanical methods. 2.2. Mechanical-chemicalMechanical-chemical - a cord is used for- a cord is used for mechanically separating the tissue frommechanically separating the tissue from the cavity margin and is impregenatedthe cavity margin and is impregenated with a- chemical for hemostasis aswith a- chemical for hemostasis as impression are made.impression are made. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 3. Surgical3. Surgical - a ribbon of gingival tissue is- a ribbon of gingival tissue is removed from the sulcus around the cavityremoved from the sulcus around the cavity margin with dental electrosurgery. Themargin with dental electrosurgery. The procedure creates a space in the tissueprocedure creates a space in the tissue surrounding the tooth, control seepage, andsurrounding the tooth, control seepage, and provides a trough for the impression material.provides a trough for the impression material. Another method is gingitage-the literature hasAnother method is gingitage-the literature has indicated successful exposure of the cavityindicated successful exposure of the cavity margin with healing comparable to dentalmargin with healing comparable to dental electrosurgery. In this technique, specialelectrosurgery. In this technique, special diamond stones remove the sulcus epitheliumdiamond stones remove the sulcus epithelium as the margins are finished beneath the crest ofas the margins are finished beneath the crest of the gingiva.the gingiva. The cast metal preparation is constructed toThe cast metal preparation is constructed to minimize tissue laceration with sub gingivalminimize tissue laceration with sub gingival margins. Tissue laceration can be reduced bymargins. Tissue laceration can be reduced by avoiding sub gingival margins and creating aavoiding sub gingival margins and creating a sulcus space by dilation with a mechanical orsulcus space by dilation with a mechanical or mechanical -chemical method.mechanical -chemical method.www.indiandentalacademy.comwww.indiandentalacademy.com
  • The entire procedure is commonly repeatedThe entire procedure is commonly repeated before making an additional impression. Whenbefore making an additional impression. When using the surgical method tissue dilation is notusing the surgical method tissue dilation is not repeated. Only cleansing and spot coagulationrepeated. Only cleansing and spot coagulation to control bleeding in the created sulcus isto control bleeding in the created sulcus is necessary. Additionally some dentists prefer tonecessary. Additionally some dentists prefer to pack an astringent medicated cord into thepack an astringent medicated cord into the surgical through to control seepage.surgical through to control seepage. Elastomeric impression material does notElastomeric impression material does not displace blood, salvia, debris, or tissue. Thedisplace blood, salvia, debris, or tissue. The tissue therefore is displaced laterally, or atissue therefore is displaced laterally, or a ribbon of tissue is removed to expose the toothribbon of tissue is removed to expose the tooth preparation margin before the impressions. Thepreparation margin before the impressions. The tissue adjacent to the exposed preparationtissue adjacent to the exposed preparation margin must also be reasonably dry and cleanmargin must also be reasonably dry and clean for accurate impressions.for accurate impressions. www.indiandentalacademy.comwww.indiandentalacademy.com
  • Mechanical tissue DilationMechanical tissue Dilation Mechanical dilation is possible, but mostMechanical dilation is possible, but most is carefully performed to minimizeis carefully performed to minimize trauma. Oversized copper bands aretrauma. Oversized copper bands are contoured to the gingiva and restrictedcontoured to the gingiva and restricted towards the preparation margin whentowards the preparation margin when gently seated over the tooth. A resin orgently seated over the tooth. A resin or compound plug is placed on the top forcompound plug is placed on the top for stability, and band is vented for escape ofstability, and band is vented for escape of excess elastomeric impression materials.excess elastomeric impression materials. A loop of dental floss is threaded throughA loop of dental floss is threaded through the vent to ease band removal after thethe vent to ease band removal after the impression material has set.impression material has set. www.indiandentalacademy.comwww.indiandentalacademy.com
  • The dentist must not exert excessiveThe dentist must not exert excessive pressure on the band, or the tissue maypressure on the band, or the tissue may be stripped from the tooth. Since tissuebe stripped from the tooth. Since tissue dilation can be accomplished effectivelydilation can be accomplished effectively by other method s mechanical dilationby other method s mechanical dilation has limited application, but is a superbhas limited application, but is a superb method to confirm gingival margins, iemethod to confirm gingival margins, ie multiple abutments, full arch impressionsmultiple abutments, full arch impressions with one or two questionable margins.with one or two questionable margins. www.indiandentalacademy.comwww.indiandentalacademy.com
  • Mechanical Chemical DilationMechanical Chemical Dilation Mechanical chemical dilation consists ofMechanical chemical dilation consists of cords impregnated with chemical that arecords impregnated with chemical that are eased into the intracrevicular spaceeased into the intracrevicular space beneath the preparation margin withoutbeneath the preparation margin without force. The area must be kept dry but notforce. The area must be kept dry but not dessicated if the hemostatic chemical indessicated if the hemostatic chemical in the cord is to have maximumthe cord is to have maximum affectiveness .After 5 to 10 minutes, theaffectiveness .After 5 to 10 minutes, the cord is gently removed and the sulcuscord is gently removed and the sulcus surrounding the preparation margin issurrounding the preparation margin is exposed and hemostasis maintained.exposed and hemostasis maintained. If bleeding is still evident, the crevice isIf bleeding is still evident, the crevice is repacked for an additional 5 minutes.repacked for an additional 5 minutes.www.indiandentalacademy.comwww.indiandentalacademy.com
  • If the area has been isolated with cottonIf the area has been isolated with cotton rolls, the packed cord is damped beforerolls, the packed cord is damped before removal, as occasionally a dry cordremoval, as occasionally a dry cord adheres to the sealed capillaries and, onadheres to the sealed capillaries and, on removal, cause bleeding. subgingivally ,removal, cause bleeding. subgingivally , the packing insrument is directed towardsthe packing insrument is directed towards the area where the cord is alreadythe area where the cord is already secure. Pushing away from the areasecure. Pushing away from the area previously retracted dislodges the cord.previously retracted dislodges the cord. Cords impregnated with alum orCords impregnated with alum or aluminium choloride provide a stypticaluminium choloride provide a styptic action to control the seepage. Hemostaticaction to control the seepage. Hemostatic agents like epinepheine are notagents like epinepheine are not recommended in patients with cardiacrecommended in patients with cardiac problems.problems. www.indiandentalacademy.comwww.indiandentalacademy.com
  • Surgical Tissue DilationSurgical Tissue Dilation Continues visualization of the subgingivalContinues visualization of the subgingival margin is difficult for the dentist. Cordsmargin is difficult for the dentist. Cords chemicals, rubber or leather rings, copperchemicals, rubber or leather rings, copper stainless steel and aluminium bands withstainless steel and aluminium bands with other materials have been suggested forother materials have been suggested for this purpose. With refinement of dentalthis purpose. With refinement of dental electro surgery, many of the problems ofelectro surgery, many of the problems of securing impressions of multiplesecuring impressions of multiple abutment preparation can be alleviated.abutment preparation can be alleviated. www.indiandentalacademy.comwww.indiandentalacademy.com
  • Electrosurgery requires profound localElectrosurgery requires profound local anesthesia. Odor is controlled by ananesthesia. Odor is controlled by an outside ventilated oral evacuator system.outside ventilated oral evacuator system. Plastic suction tips are used, sincePlastic suction tips are used, since momentary contact of an activatedmomentary contact of an activated working electrode with a metal aspiratorworking electrode with a metal aspirator tip causes spot coagulation where evertip causes spot coagulation where ever the metal touches the tissue. For thethe metal touches the tissue. For the same reason, plastic mounted mouthsame reason, plastic mounted mouth mirrors are indicated. The passive ormirrors are indicated. The passive or indifferent plate is positioned under theindifferent plate is positioned under the patient's shoullder for biterminalpatient's shoullder for biterminal application. Monoterminal applicationsapplication. Monoterminal applications are rare.are rare. www.indiandentalacademy.comwww.indiandentalacademy.com
  • CURRENTS AND ELECTRODE SELECTIONCURRENTS AND ELECTRODE SELECTION Selection of electrodes varies, depending onSelection of electrodes varies, depending on the tooth and its arch position. This procedurethe tooth and its arch position. This procedure can be performed without patient discomfort incan be performed without patient discomfort in relatively bloodless field. With each electroderelatively bloodless field. With each electrode the basics of electrosurgery are sustained. Thethe basics of electrosurgery are sustained. The working electrode must be clean and withoutworking electrode must be clean and without carbonization. In exacting marginal dilation, acarbonization. In exacting marginal dilation, a carbonised electrode has a tendency to drag,carbonised electrode has a tendency to drag, tearing the tissue and causing bleeding. If atearing the tissue and causing bleeding. If a straight wire tip, varitip, or minute continuousstraight wire tip, varitip, or minute continuous loop electrode is used; they should be cleanedloop electrode is used; they should be cleaned between each application.between each application. www.indiandentalacademy.comwww.indiandentalacademy.com
  • The depth of tissue removal is determined byThe depth of tissue removal is determined by the morphology of the tissue and the biologicthe morphology of the tissue and the biologic width. The tissue should extend about 0.3 towidth. The tissue should extend about 0.3 to 0.5 mm below the margin of the cast0.5 mm below the margin of the cast restoration for definite margin detection in therestoration for definite margin detection in the impression and on the master dies. When usingimpression and on the master dies. When using a continuous loop there is usually a smalla continuous loop there is usually a small amount of tissue left beneath of the marginamount of tissue left beneath of the margin because of the shape of the loop. This tissuebecause of the shape of the loop. This tissue tag is removed using a single-wire or variable-tag is removed using a single-wire or variable- tip electrode wire. The variable-tip electrodetip electrode wire. The variable-tip electrode wire can be adjusted to the desired length. Thewire can be adjusted to the desired length. The troughting procedure is pressureless, and iftroughting procedure is pressureless, and if additional tissue refinement is required, a timeadditional tissue refinement is required, a time laps of at least 5 second is needed to dissipatelaps of at least 5 second is needed to dissipate heat.heat. www.indiandentalacademy.comwww.indiandentalacademy.com
  • Posner ElectrodePosner Electrode With the AP 1½ electrode, the insulatedWith the AP 1½ electrode, the insulated portion of the electrode is directedportion of the electrode is directed around the tooth, removing the gingivalaround the tooth, removing the gingival sulcular epithelium. The 1½ disignation ofsulcular epithelium. The 1½ disignation of the AP 1½ mm beyond the insulation.the AP 1½ mm beyond the insulation. This offers a precise, uniform 1½ mmThis offers a precise, uniform 1½ mm sulcus depth incision. If less trough depthsulcus depth incision. If less trough depth is desired, part of the tip is removed tois desired, part of the tip is removed to create the desired depth at 0.5 mm, 0.75create the desired depth at 0.5 mm, 0.75 mm, or 1.0 mm.mm, or 1.0 mm. www.indiandentalacademy.comwww.indiandentalacademy.com
  • Electrode TipElectrode Tip Variable-tip or straight-wire electrodes are popular.Variable-tip or straight-wire electrodes are popular. Tooth preparation with the desired margin isTooth preparation with the desired margin is completed, and margins are terminated above thecompleted, and margins are terminated above the soft tissue. The single wire of the variable tip issoft tissue. The single wire of the variable tip is adjusted to the desired subgingival depth, and theadjusted to the desired subgingival depth, and the tooth is then circumscribed by repeatedtooth is then circumscribed by repeated approaches around the tooth in segments. First theapproaches around the tooth in segments. First the lingual subgingival trough; then the facial surface;lingual subgingival trough; then the facial surface; and then the mesial and distal surfaces areand then the mesial and distal surfaces are established. This prevents heat accumulation in theestablished. This prevents heat accumulation in the tissue. For most dentists, it is virtually impossibletissue. For most dentists, it is virtually impossible to circumscribe a tooth with one or two connectingto circumscribe a tooth with one or two connecting passes. If a straight-wire electrode or the variable-passes. If a straight-wire electrode or the variable- tip electrode is used, the operator may find thattip electrode is used, the operator may find that the electrode is too fine to remove enough tissuethe electrode is too fine to remove enough tissue to provide adequate bulk of impression material into provide adequate bulk of impression material in the sulcus.the sulcus. www.indiandentalacademy.comwww.indiandentalacademy.com
  • This is especially true if the end of the workingThis is especially true if the end of the working electrode is positioned parallel with the longelectrode is positioned parallel with the long axis of the tooth. By angling the workingaxis of the tooth. By angling the working electrode at approximately 15 to 20 degreeselectrode at approximately 15 to 20 degrees and carrying the tip through the tissue until itand carrying the tip through the tissue until it rests against the tooth, a small wedge of tissuerests against the tooth, a small wedge of tissue can be removed. If bleeding occurs, it is usuallycan be removed. If bleeding occurs, it is usually interproximal and controlled with the sameinterproximal and controlled with the same electrode using coagulation current. Anotherelectrode using coagulation current. Another method uses equal parts of hydrogen peroxidemethod uses equal parts of hydrogen peroxide and water to arrest slight local hemorrhage.and water to arrest slight local hemorrhage. After the area is dry, the extended sulcus isAfter the area is dry, the extended sulcus is debris free and the root and crown easilydebris free and the root and crown easily visualized. The margins can then be finished tovisualized. The margins can then be finished to the desired depth, the area again flushed withthe desired depth, the area again flushed with water and peroxide and the impressionswater and peroxide and the impressions secured.secured. www.indiandentalacademy.comwww.indiandentalacademy.com
  • In the anterior quadrants where theIn the anterior quadrants where the gingiva is especially thin, the angle of thegingiva is especially thin, the angle of the working electrode is changed to be moreworking electrode is changed to be more nearly parallel to the long axis of thenearly parallel to the long axis of the tooth.tooth. Again with the segmented approach, theAgain with the segmented approach, the sulcular epithelium is removed, and if asulcular epithelium is removed, and if a narrow facial-lingual sulcus has beennarrow facial-lingual sulcus has been created, the cord is placed before thecreated, the cord is placed before the impression to retract the tissue awayimpression to retract the tissue away from the tooth. It is axiomatic that thefrom the tooth. It is axiomatic that the treatment restoration be suitably adaptedtreatment restoration be suitably adapted to the existing margins without lutingto the existing margins without luting material impinging on the regeneratingmaterial impinging on the regenerating sulcular epithelium.sulcular epithelium. www.indiandentalacademy.comwww.indiandentalacademy.com
  • Dental impressions ideally extend 0.3 to 0.5 mmDental impressions ideally extend 0.3 to 0.5 mm below the preparation margin to ensure accuracy.below the preparation margin to ensure accuracy. Electro-surgical removal of a ribbon of tissueElectro-surgical removal of a ribbon of tissue around the preparation margin provides necessaryaround the preparation margin provides necessary space for adequate bulk of the elastic impressionspace for adequate bulk of the elastic impression material.material. After securing the final impression or impressions,After securing the final impression or impressions, tincutre of myrrh and benzoin (Oringer's solution)tincutre of myrrh and benzoin (Oringer's solution) is placed on the surgical area and air dried, thisis placed on the surgical area and air dried, this procedure is repeated three to five times beforeprocedure is repeated three to five times before the treatment restoration is placed. Orabase maythe treatment restoration is placed. Orabase may replace or supplement myrrh and benzoin in thisreplace or supplement myrrh and benzoin in this procedure. The tissue healing is rapid, and theprocedure. The tissue healing is rapid, and the subgingival trough heals in 5 to 7 days. Disciplinesubgingival trough heals in 5 to 7 days. Discipline is imperative to the uneventful exposure of theis imperative to the uneventful exposure of the cavity margin for making impressions for castcavity margin for making impressions for cast restorations. Tissue trauma, expenditure of time,restorations. Tissue trauma, expenditure of time, and the shrinkage of tissue restricts traditionaland the shrinkage of tissue restricts traditional mechanical tissue dilation.mechanical tissue dilation. www.indiandentalacademy.comwww.indiandentalacademy.com
  • The mechanical-chemical method withThe mechanical-chemical method with cords can reduce trauma to the tissue butcords can reduce trauma to the tissue but may produce a thin layer of impressionmay produce a thin layer of impression material at the preparation margin oncematerial at the preparation margin once the cord is removed, since the tissuethe cord is removed, since the tissue returns immediately to its originalreturns immediately to its original position. If a thin layer ofposition. If a thin layer of Impression material persists; marginalImpression material persists; marginal distortion of the individual dies resultsdistortion of the individual dies results because of insufficient material in abecause of insufficient material in a critical area.critical area. www.indiandentalacademy.comwww.indiandentalacademy.com
  • Dental electrosugery provides a rapidDental electrosugery provides a rapid efficient method for tissue dilation, withefficient method for tissue dilation, with adequate impression material in crucialadequate impression material in crucial areas. It does not cause significantareas. It does not cause significant shrinkage of the tissue or patientshrinkage of the tissue or patient discomfort if appropriate post operativediscomfort if appropriate post operative medication is used.medication is used. The key factors for successful electroThe key factors for successful electro surgery are: profound anesthesia;surgery are: profound anesthesia; appropriate current selection; a lightappropriate current selection; a light stroke with a 5 second time intervalstroke with a 5 second time interval between applications of the electrode;between applications of the electrode; and maintaining the biologic width afterand maintaining the biologic width after tissue healing.tissue healing. www.indiandentalacademy.comwww.indiandentalacademy.com
  • TEMPORARY AND PROVISIONAL CROWNS:TEMPORARY AND PROVISIONAL CROWNS: Temporary and provisional crowns withTemporary and provisional crowns with intracrevicular margins are usuallyintracrevicular margins are usually associated with gingival recession. Theassociated with gingival recession. The gingiva recovers its original position aftergingiva recovers its original position after the permanent crown is in place, but thethe permanent crown is in place, but the possibility of permanent recessionpossibility of permanent recession increases the longer the temporaryincreases the longer the temporary restoration is in place. Gingival recessionrestoration is in place. Gingival recession is avoided around temporary crowns byis avoided around temporary crowns by careful preparations and by makingcareful preparations and by making contours of the treatment restorationcontours of the treatment restoration resemble those of the natural teeth.resemble those of the natural teeth.www.indiandentalacademy.comwww.indiandentalacademy.com
  • EMBRASURES:EMBRASURES: Restorative dental procedures too often resultRestorative dental procedures too often result in the restorative materials taking up place thatin the restorative materials taking up place that is normally occupied by the interdental papilla.is normally occupied by the interdental papilla. This problem has been accentuated with theThis problem has been accentuated with the advent of restorations in which porcelain isadvent of restorations in which porcelain is bounded to metal. The problem begins whenbounded to metal. The problem begins when there is under preparation of the tooth, so thatthere is under preparation of the tooth, so that the technician is left with no other choicethe technician is left with no other choice except to place an excessive amount ofexcept to place an excessive amount of restorative material into the inter proximalrestorative material into the inter proximal space. During the preparation of dies for castspace. During the preparation of dies for cast preparation, the technician first removes all thepreparation, the technician first removes all the replicated gingival tissue to gain access to thereplicated gingival tissue to gain access to the margins, thus it is impossible to visualize themargins, thus it is impossible to visualize the space available for dental restorations in thespace available for dental restorations in the inter proximal enclosure areas.inter proximal enclosure areas.www.indiandentalacademy.comwww.indiandentalacademy.com
  • If two models are poured from the sameIf two models are poured from the same impression and the second one is used as animpression and the second one is used as an indication of how much space is currentlyindication of how much space is currently occupied by the gingival tissues, the technicianoccupied by the gingival tissues, the technician can have a better understanding of what thecan have a better understanding of what the contour of the final restoration should be. Overcontour of the final restoration should be. Over crowding of the inter dental space results in acrowding of the inter dental space results in a narrowed embrasure area that makesnarrowed embrasure area that makes maintaining oral hygiene difficult. The spacemaintaining oral hygiene difficult. The space available for gingival tissues is reduced also, soavailable for gingival tissues is reduced also, so that a thin strand of collagen is often all thatthat a thin strand of collagen is often all that can occupy this place. This reduction in thecan occupy this place. This reduction in the space available for the gingiva means that thespace available for the gingiva means that the space where collagen should form an effectivespace where collagen should form an effective seal in association with the junctionalseal in association with the junctional epithelium is diminished.epithelium is diminished. www.indiandentalacademy.comwww.indiandentalacademy.com
  • This may lead to periodontal destruction,This may lead to periodontal destruction, pocket formation and bone loss. In fixed bridgepocket formation and bone loss. In fixed bridge work the soldered joint is frequently carried toowork the soldered joint is frequently carried too far in an apical direction and so it invades thefar in an apical direction and so it invades the embrasure space from its coronal aspect. Thisembrasure space from its coronal aspect. This also leads to inadequate space for thealso leads to inadequate space for the interdental papilla. For patients who requireinterdental papilla. For patients who require increased strength in a soldered joint it is bestincreased strength in a soldered joint it is best obtained by extending the soldered jointobtained by extending the soldered joint buccally and lingually. The Prosthodontist andbuccally and lingually. The Prosthodontist and not the technician should determine the size ofnot the technician should determine the size of the soldered joint because he is aware of howthe soldered joint because he is aware of how much gingiva is available in the inter proximalmuch gingiva is available in the inter proximal embrasure.embrasure. www.indiandentalacademy.comwww.indiandentalacademy.com
  • BIOLOGIC WIDTH EMBRASURES:BIOLOGIC WIDTH EMBRASURES: The teeth touch in area called proximalThe teeth touch in area called proximal contact, the spaces below the contact arecontact, the spaces below the contact are known as embrasures. In health, theknown as embrasures. In health, the embrasures are usually filled with tissue.embrasures are usually filled with tissue. Embrasures protect the gingiva from foodEmbrasures protect the gingiva from food impaction and deflect the food, toimpaction and deflect the food, to massage the gingival surface. Theymassage the gingival surface. They provide spillways for food duringprovide spillways for food during mastication and relieve occlusal forcesmastication and relieve occlusal forces when resistant food is chewed.when resistant food is chewed. The proximal surfaces of dentalThe proximal surfaces of dental restorations are important because theyrestorations are important because they determine the embrasures essential fordetermine the embrasures essential for gingival health.gingival health. www.indiandentalacademy.comwww.indiandentalacademy.com
  • In disease and periodontal therapy thisIn disease and periodontal therapy this tissue is reduced, the new restorationstissue is reduced, the new restorations create another embrasure that will locatecreate another embrasure that will locate the restorations close to the new level ofthe restorations close to the new level of the gingiva. The proximal surfaces ofthe gingiva. The proximal surfaces of crowns should taper away from thecrowns should taper away from the contact area on all surfaces. Excessivelycontact area on all surfaces. Excessively broad proximal contact areas andbroad proximal contact areas and inadequate contour in the cervical areasinadequate contour in the cervical areas suppress the gingival papillae. Thesesuppress the gingival papillae. These prominent papillae trap food debris,prominent papillae trap food debris, leading to gingival inflammation.leading to gingival inflammation. www.indiandentalacademy.comwww.indiandentalacademy.com
  • Proximal contacts that are too narrowProximal contacts that are too narrow buccolingually create enlargedbuccolingually create enlarged embrasures without sufficient protectionembrasures without sufficient protection against interdental food impaction. Theagainst interdental food impaction. The inter dental brush (proxa brush) andinter dental brush (proxa brush) and dental floss are effective in deplaquingdental floss are effective in deplaquing the tooth surface at the gingival margin.the tooth surface at the gingival margin. The proximal contact should be such thatThe proximal contact should be such that the brush snuggly fits in the embrasurethe brush snuggly fits in the embrasure areas.areas. www.indiandentalacademy.comwww.indiandentalacademy.com
  • PONTICS:PONTICS: Porter recommends the elimination ofPorter recommends the elimination of embrasures between pontics to simplify oralembrasures between pontics to simplify oral hygiene and curtain saliva expectoration.hygiene and curtain saliva expectoration. The ridge lap and conical shape designs areThe ridge lap and conical shape designs are infrequently recommended. The ridge lapinfrequently recommended. The ridge lap creates an uncleansible contact area leading tocreates an uncleansible contact area leading to inflammation of the edentulous mucosa belowinflammation of the edentulous mucosa below the prosthesis.the prosthesis. The spheriodal pontic contacts without pressureThe spheriodal pontic contacts without pressure the top of the ridge at the buccal surface,the top of the ridge at the buccal surface, depending upon the relationship of the residualdepending upon the relationship of the residual ridge to the opposing dentition. All in all aridge to the opposing dentition. All in all a pontic should have only minimal passivepontic should have only minimal passive contact with the ridge, excessive pressurecontact with the ridge, excessive pressure causes inflammation and proliferation of thecauses inflammation and proliferation of the tissues. The pontic should not blanch thetissues. The pontic should not blanch the tissues or be placed on the movable mucosa.tissues or be placed on the movable mucosa.www.indiandentalacademy.comwww.indiandentalacademy.com
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  • CONTOURS OF RESTORATIONS:CONTOURS OF RESTORATIONS: The facial and lingual contours of restorationsThe facial and lingual contours of restorations are also important in the preservation ofare also important in the preservation of gingiva health. The most common error ingingiva health. The most common error in creating the contours of the tooth in dentalcreating the contours of the tooth in dental restorations is over contouring of facial andrestorations is over contouring of facial and lingual surfaces. This overcontouring generallylingual surfaces. This overcontouring generally occurs in the gingival third of the crown andoccurs in the gingival third of the crown and results in an area where oral hygieneresults in an area where oral hygiene procedures are unable to control plaque.procedures are unable to control plaque. Consequently plaque accumulates and gingivaConsequently plaque accumulates and gingiva becomes inflamed. Over contouring on thebecomes inflamed. Over contouring on the buccal or labial surfaces frequently in porcelainbuccal or labial surfaces frequently in porcelain fused to metal crowns owing to the techniciansfused to metal crowns owing to the technicians attempt to obtain a thickness of porcelainattempt to obtain a thickness of porcelain adequate to mask the underlying metal andadequate to mask the underlying metal and provide an aesthetic appearance to the crown.provide an aesthetic appearance to the crown.www.indiandentalacademy.comwww.indiandentalacademy.com
  • Hence, it is important for the Prosthodontist toHence, it is important for the Prosthodontist to remove enough tooth material during toothremove enough tooth material during tooth preparation. In patients in whom periodontalpreparation. In patients in whom periodontal disease causes the gingival margin to be in adisease causes the gingival margin to be in a much apical position than it was during health,much apical position than it was during health, the facial and lingual contours become eventhe facial and lingual contours become even more significant. In these cases the bulge onmore significant. In these cases the bulge on the facial contour of the crown which would bethe facial contour of the crown which would be sub gingival normally appears supra gingivally.sub gingival normally appears supra gingivally. This makes the position of the exposed rootThis makes the position of the exposed root immediately apical to the bulge less accessibleimmediately apical to the bulge less accessible for oral hygiene with resultant plaquefor oral hygiene with resultant plaque accumulation and gingival inflammation.accumulation and gingival inflammation. www.indiandentalacademy.comwww.indiandentalacademy.com
  • OCCLUSAL SURFACE:OCCLUSAL SURFACE: They should restore occlusal dimensionsThey should restore occlusal dimensions and cuspal contours in harmony withand cuspal contours in harmony with remainder of the natural dentition afterremainder of the natural dentition after occlusal abnormalities have beenocclusal abnormalities have been eliminated by occlusal adjustment. Theeliminated by occlusal adjustment. The occlusal surface of the teeth should notocclusal surface of the teeth should not be arbitrarily narrowed. Proper occlusalbe arbitrarily narrowed. Proper occlusal relationships are more important than therelationships are more important than the width of the occlusal table in thewidth of the occlusal table in the attainment of physiologic occlusalattainment of physiologic occlusal surfaces. The anatomy of the occlusalsurfaces. The anatomy of the occlusal surface should provide well formedsurface should provide well formed marginal ridges and occlusal sluicewaysmarginal ridges and occlusal sluiceways to prevent inter proximal food impaction.to prevent inter proximal food impaction. www.indiandentalacademy.comwww.indiandentalacademy.com
  • EFFECT OF SURFACE FINISH ON THEEFFECT OF SURFACE FINISH ON THE PERIODONTIUM:PERIODONTIUM: The surface of the restorations should be asThe surface of the restorations should be as smooth as possible to limit plaquesmooth as possible to limit plaque accumulation. All restorations should have aaccumulation. All restorations should have a very high polish and smooth surface texture.very high polish and smooth surface texture. CEMENTATION:CEMENTATION: Retained cement particles irritate the gingivaRetained cement particles irritate the gingiva and should be removed. It is important that theand should be removed. It is important that the restoration be sealed as close to the toothrestoration be sealed as close to the tooth preparation as possible. After cementation it ispreparation as possible. After cementation it is very important that no cement is left in thevery important that no cement is left in the interproximal spaces. Oral hygiene proceduresinterproximal spaces. Oral hygiene procedures become a problem if the cement is left behind.become a problem if the cement is left behind. Hence floss should be passed along theHence floss should be passed along the interproximal margins to ensure that no cementinterproximal margins to ensure that no cement is left back and the margins are free.is left back and the margins are free. www.indiandentalacademy.comwww.indiandentalacademy.com
  • GINGIVAL FINISH LINES:GINGIVAL FINISH LINES: Margins are one of the most importantMargins are one of the most important and weakest lines in the success of anyand weakest lines in the success of any fixed partial denture restorations. Toothfixed partial denture restorations. Tooth preparations for fixed prosthodonticspreparations for fixed prosthodontics requires a decision regarding therequires a decision regarding the marginal configurations. The designmarginal configurations. The design dictates the shape and bulk of the castingdictates the shape and bulk of the casting and influences the fit at the margin.and influences the fit at the margin. Although many factors such as materials,Although many factors such as materials, esthetics and access influence thisesthetics and access influence this selection, most dentists probably have aselection, most dentists probably have a preferred design. However, there ispreferred design. However, there is disagreement about what constitutesdisagreement about what constitutes ideal margin, geometry and width.ideal margin, geometry and width. www.indiandentalacademy.comwww.indiandentalacademy.com
  • GINGIVAL TERMINATION OF TOOTHGINGIVAL TERMINATION OF TOOTH PREPARATION:PREPARATION: Tooth preparations terminate in a finishTooth preparations terminate in a finish line. Some terminate on the occlusal andline. Some terminate on the occlusal and axial surfaces and are referred to as cavoaxial surfaces and are referred to as cavo surface angles. The most controversial,surface angles. The most controversial, however, are the gingival finish lines.however, are the gingival finish lines. The previous recommendations were toThe previous recommendations were to extend crown margins into theextend crown margins into the intracrevicular space because the gingivalintracrevicular space because the gingival crevice was supposed to be immune tocrevice was supposed to be immune to caries. Deviation from this norm wascaries. Deviation from this norm was supposed to be irresponsible, despite thesupposed to be irresponsible, despite the fact that strong evidence supportedfact that strong evidence supported supragingival margins.supragingival margins. www.indiandentalacademy.comwww.indiandentalacademy.com
  • Conversely, subgingival margins areConversely, subgingival margins are considered necessary for the followingconsidered necessary for the following reasons:reasons: a). Esthetics.a). Esthetics. b). Presence of existing restorationsb). Presence of existing restorations extending into the intracrevicular space.extending into the intracrevicular space. c). Insufficient vertical length forc). Insufficient vertical length for retention.retention. d). Higher D.M.F rate of youngerd). Higher D.M.F rate of younger patients.patients. One commonly ommited fact is that theOne commonly ommited fact is that the soft tissue approximating the tooth issoft tissue approximating the tooth is usually unhealthy before preparation.usually unhealthy before preparation. www.indiandentalacademy.comwww.indiandentalacademy.com
  • Therefore, the removal of tissue withTherefore, the removal of tissue with questionable architecture and re growth ofquestionable architecture and re growth of healthier tissue is a rational direction ofhealthier tissue is a rational direction of treatment. Interceptive periodontics resultingtreatment. Interceptive periodontics resulting from the early recognition of tissue symptomsfrom the early recognition of tissue symptoms is recommended.is recommended. Question, where the finish lines should beQuestion, where the finish lines should be placed for proper contour of the restorationplaced for proper contour of the restoration requires analysis. The sub gingival area is notrequires analysis. The sub gingival area is not an immune area. Additionally, if there is anyan immune area. Additionally, if there is any validity to the theory of passive eruption, thevalidity to the theory of passive eruption, the sub gingival margin could become suprasub gingival margin could become supra gingival in a short time. Therefore, the dentist’sgingival in a short time. Therefore, the dentist’s evaluation should include enquiry into theevaluation should include enquiry into the longevity of the restoration.longevity of the restoration.www.indiandentalacademy.comwww.indiandentalacademy.com
  • MARGIN PLACEMENT:MARGIN PLACEMENT: Whenever possible, the margin of theWhenever possible, the margin of the preparations should be supra gingival.preparations should be supra gingival. Sub gingival margins of cementedSub gingival margins of cemented restorations have been identified as arestorations have been identified as a major factor in periodontal diseases,major factor in periodontal diseases, particularly where they encroach uponparticularly where they encroach upon the epithelial attachment. Supra gingivalthe epithelial attachment. Supra gingival margins are easier to prepare accuratelymargins are easier to prepare accurately without trauma to the soft tissues. Theywithout trauma to the soft tissues. They can usually also be situated on hardcan usually also be situated on hard enamel whereas sub gingival margins areenamel whereas sub gingival margins are often on dentin or cementum.often on dentin or cementum.www.indiandentalacademy.comwww.indiandentalacademy.com
  • Other advantages of supra gingivalOther advantages of supra gingival margins include the following:margins include the following: a). They can be easily finished.a). They can be easily finished. b). They are more easily kept clean.b). They are more easily kept clean. c). Impressions are more easily made, withc). Impressions are more easily made, with less potential for soft tissue damage.less potential for soft tissue damage. d). Restorations can be easily evaluated atd). Restorations can be easily evaluated at recall appointments.recall appointments. www.indiandentalacademy.comwww.indiandentalacademy.com
  • However, a sub gingival margin is justified ifHowever, a sub gingival margin is justified if any of the following pertain:any of the following pertain: a). Dental caries, cervical erosions ora). Dental caries, cervical erosions or restorations extend sub gingivally and a crownrestorations extend sub gingivally and a crown lengthening procedure is not indicated.lengthening procedure is not indicated. b). The proximal contact area extends to theb). The proximal contact area extends to the gingival crest.gingival crest. c). Additional retention is needed.c). Additional retention is needed. d). The margin of a metal ceramic crown is tod). The margin of a metal ceramic crown is to be hidden behind the labiogingival crest.be hidden behind the labiogingival crest. e). Root sensitivity cannot be controlled bye). Root sensitivity cannot be controlled by more conservative procedures.more conservative procedures. f). Modification of the axial contour is indicated.f). Modification of the axial contour is indicated. www.indiandentalacademy.comwww.indiandentalacademy.com
  • MARGIN ADAPTATION:MARGIN ADAPTATION: The junction between a cemented restorationThe junction between a cemented restoration and the tooth is always a potential site forand the tooth is always a potential site for recurrent caries because of the dissolution ofrecurrent caries because of the dissolution of the luting agent. Where possible it should bethe luting agent. Where possible it should be kept as short as possible. Rough or irregularkept as short as possible. Rough or irregular junctions greatly increase the length of thejunctions greatly increase the length of the margins and reduce the possibility of obtainingmargins and reduce the possibility of obtaining a good fitting restoration. The importance ofa good fitting restoration. The importance of smooth margins is emphasized. Time spentsmooth margins is emphasized. Time spent obtaining a smooth margin will make theobtaining a smooth margin will make the subsequent steps of tissue displacement,subsequent steps of tissue displacement, impression making die formation, waxing andimpression making die formation, waxing and finishing much easier and ultimately willfinishing much easier and ultimately will provide the patient with a longer lastingprovide the patient with a longer lasting restoration.restoration. www.indiandentalacademy.comwww.indiandentalacademy.com
  • MARGIN GEOMETRY:MARGIN GEOMETRY: The cross-sectional configuration of the margin hasThe cross-sectional configuration of the margin has been the subject of much analysis and debate.been the subject of much analysis and debate. Different shapes have been described and advocated.Different shapes have been described and advocated. For evaluation the following guidelines should beFor evaluation the following guidelines should be considered:considered: a). It should be easy to prepare without over extension.a). It should be easy to prepare without over extension. b). It should be readily identified in the impression andb). It should be readily identified in the impression and on the die.on the die. c). It should give a distinct margin to which the waxc). It should give a distinct margin to which the wax pattern can be finished.pattern can be finished. d). It should provide for sufficient bulk of material. Thisd). It should provide for sufficient bulk of material. This will enable the wax pattern to be handled withoutwill enable the wax pattern to be handled without distortion as well as give the restoration strength and,distortion as well as give the restoration strength and, where porcelain is used esthetics.where porcelain is used esthetics. e). It should be as conservative as possible providede). It should be as conservative as possible provided the other criteria are met.the other criteria are met. www.indiandentalacademy.comwww.indiandentalacademy.com
  • TYPES OF FINISH LINES:TYPES OF FINISH LINES: Feather edge or shoulder less:Feather edge or shoulder less: FeatherFeather edge or shoulder less crown preparationsedge or shoulder less crown preparations should be avoided because although theyshould be avoided because although they are conservative preparations; they failare conservative preparations; they fail to provide adequate bulk at the margins.to provide adequate bulk at the margins. Over contoured restorations are often theOver contoured restorations are often the result of featheredge margins; this isresult of featheredge margins; this is because the technicians can handle thebecause the technicians can handle the wax pattern without distortion only bywax pattern without distortion only by increasing the bulk of the margins.increasing the bulk of the margins. www.indiandentalacademy.comwww.indiandentalacademy.com
  • •A. Feather edge •B. Chisel •C. Chamfer •D. Bevel •E. Shoulder •F. Sloped shoulder •G. Beveled shoulderwww.indiandentalacademy.comwww.indiandentalacademy.com
  • A variation of the feather edge, theA variation of the feather edge, the chiselchisel edge margin,edge margin, is formed when there is a largeris formed when there is a larger angle between the axial surfaces and theangle between the axial surfaces and the unprepared tooth structure. Unfortunately thisunprepared tooth structure. Unfortunately this is frequently associated with an excessivelyis frequently associated with an excessively tapered preparation or one in which the axialtapered preparation or one in which the axial reduction is not correctly aligned with the longreduction is not correctly aligned with the long axis of the tooth.axis of the tooth. Under most circumstances,Under most circumstances, feather edge andfeather edge and chisel edges are unacceptablechisel edges are unacceptable. Historically. Historically their main advantage was that they facilitatedtheir main advantage was that they facilitated the making of modeling compoundthe making of modeling compound impressions in copper bands. Since there wasimpressions in copper bands. Since there was ledge on which a band could catch.ledge on which a band could catch. www.indiandentalacademy.comwww.indiandentalacademy.com
  • Chamfer margin:Chamfer margin: is particularly suitable for castis particularly suitable for cast metal crowns and the metal only portion of metalmetal crowns and the metal only portion of metal ceramic. It is distinct, leaves adequate bulk ofceramic. It is distinct, leaves adequate bulk of material, and can be placed with precision.material, and can be placed with precision. Probably the most suitable instrument for makingProbably the most suitable instrument for making a chamfer margin is a tapered diamond bur witha chamfer margin is a tapered diamond bur with a rounded tip the margin being formed as thea rounded tip the margin being formed as the exact image of the instrument. The accuracy ofexact image of the instrument. The accuracy of the margin depends on having a high qualitythe margin depends on having a high quality diamond and true running hand piece. Thediamond and true running hand piece. The gingival margin is prepared with the diamondgingival margin is prepared with the diamond held precisely in the path of withdrawl of theheld precisely in the path of withdrawl of the restoration. Tilting it away from the tooth willrestoration. Tilting it away from the tooth will create an undercut whereas angling it towardscreate an undercut whereas angling it towards the tooth will lead to over reduction and loss ofthe tooth will lead to over reduction and loss of retention. The chamfer should never be preparedretention. The chamfer should never be prepared wider than half the tip of the diamond, lest anwider than half the tip of the diamond, lest an unsupported lip of enamel result.unsupported lip of enamel result.www.indiandentalacademy.comwww.indiandentalacademy.com
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  • Under some circumstances a beveledUnder some circumstances a beveled margin is more suitable for castmargin is more suitable for cast restorations, particularly if a ledge orrestorations, particularly if a ledge or shoulder already exists, possibly fromshoulder already exists, possibly from dental caries, cervical erosion or adental caries, cervical erosion or a previous restoration. The objective inprevious restoration. The objective in beveling is three foldbeveling is three fold • To allow the cast metal margin to be bentTo allow the cast metal margin to be bent or burnished against the prepared toothor burnished against the prepared tooth structure.structure. • To minimize the marginal discrepancyTo minimize the marginal discrepancy caused by the complete crown that fails tocaused by the complete crown that fails to seat completely andseat completely and • To protect the unprepared tooth structureTo protect the unprepared tooth structure from chipping.from chipping.www.indiandentalacademy.comwww.indiandentalacademy.com
  • Because aBecause a shoulder marginshoulder margin allows for roomallows for room for porcelain, it is recommended for an allfor porcelain, it is recommended for an all ceramic crown and the facial part of a metalceramic crown and the facial part of a metal ceramic crown. It should form a 90 degreeceramic crown. It should form a 90 degree angle with the unprepared tooth surface. Anangle with the unprepared tooth surface. An acute angle is likely to chip.acute angle is likely to chip. Some authorities have recommended a heavySome authorities have recommended a heavy chamfer rather than a shoulder margin, andchamfer rather than a shoulder margin, and some find a chamfer easier to prepare withsome find a chamfer easier to prepare with precision. However, experimental studiesprecision. However, experimental studies show that a metal framework with a shouldershow that a metal framework with a shoulder margin distorts less than a chamfer marginmargin distorts less than a chamfer margin during porcelain fixing presumably because ofduring porcelain fixing presumably because of the additional bulk provided by the shoulder.the additional bulk provided by the shoulder. www.indiandentalacademy.comwww.indiandentalacademy.com
  • To conclude, the margin is one of theTo conclude, the margin is one of the components of the cast restoration mostcomponents of the cast restoration most susceptible to failure, both biologically andsusceptible to failure, both biologically and mechanically. Most of the investigative proofmechanically. Most of the investigative proof shows that supragingival margins are kinder toshows that supragingival margins are kinder to the gingival than are subgingival margins.the gingival than are subgingival margins. However, practicality dictates that supragingivalHowever, practicality dictates that supragingival margins are not always usable. There is somemargins are not always usable. There is some indication that quality of the margin may be ofindication that quality of the margin may be of as much importance to gingival health asas much importance to gingival health as location. Research on the configuration oflocation. Research on the configuration of margins seems to agree with the majority ofmargins seems to agree with the majority of authors writing technical articles. Most agreeauthors writing technical articles. Most agree that feather edge or knife edge margins are notthat feather edge or knife edge margins are not always the most acceptable. Apparently bulkyalways the most acceptable. Apparently bulky margins with rounded internal line angles aremargins with rounded internal line angles are best.best. www.indiandentalacademy.comwww.indiandentalacademy.com
  •  Complete shoulders are the classic finish linesComplete shoulders are the classic finish lines for complete porcelain crowns.for complete porcelain crowns.  Beveled shoulders are used in preparations forBeveled shoulders are used in preparations for veneers and selected posterior teeth.veneers and selected posterior teeth.  The chamfer possessed internal bulk andThe chamfer possessed internal bulk and satisfactory margin adaptation extrasatisfactory margin adaptation extra coronally; it is the traditional gingivalcoronally; it is the traditional gingival termination for posterior crowns and thetermination for posterior crowns and the lingual surfaces of anterior ceramic / metallingual surfaces of anterior ceramic / metal crowns.crowns.  Knife edge finish lines are used for youngerKnife edge finish lines are used for younger patients, pin ledge three quarter crowns,patients, pin ledge three quarter crowns, inaccessible areas of the oral cavity, and finishinaccessible areas of the oral cavity, and finish lines on the cementum.lines on the cementum. www.indiandentalacademy.comwww.indiandentalacademy.com
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  • SUMMARY AND CONCLUSIONSUMMARY AND CONCLUSION One of the primary goals of restorative therapyOne of the primary goals of restorative therapy is to establish a physiologic periodontal climateis to establish a physiologic periodontal climate and facilitate the maintenance of periodontaland facilitate the maintenance of periodontal health. Traumatic occlusal relationships shouldhealth. Traumatic occlusal relationships should be eliminated before restorative procedures arebe eliminated before restorative procedures are begun and restorations should be constructedbegun and restorations should be constructed in conformity with the newly establishedin conformity with the newly established occlusal patterns. If this is not done theocclusal patterns. If this is not done the prostheis will perpetuate occlusal relationshipprostheis will perpetuate occlusal relationship injurious to the periodontium. Subgingivalinjurious to the periodontium. Subgingival margins should be avoided as far as possiblemargins should be avoided as far as possible except in cases of caries, extending apically,except in cases of caries, extending apically, short crowns hence to obtain retention, and inshort crowns hence to obtain retention, and in labial surfaces of anterior maxillary teeth inlabial surfaces of anterior maxillary teeth in patients who demand for esthetics as a primarypatients who demand for esthetics as a primary criteria.criteria. www.indiandentalacademy.comwww.indiandentalacademy.com
  • In impression making, ginival retractionIn impression making, ginival retraction methods should be followed deligently keepingmethods should be followed deligently keeping the ginival health in mind. All interimthe ginival health in mind. All interim restorations should be so constructed that theyrestorations should be so constructed that they cause no trauma to the gingival during the timecause no trauma to the gingival during the time they are in the mouth. The teeth should taperthey are in the mouth. The teeth should taper away from their proximal contacts to get goodaway from their proximal contacts to get good healthy embrasures. Over contouring of thehealthy embrasures. Over contouring of the facial and lingual surfaces should be avoided.facial and lingual surfaces should be avoided. Over contouring in gingival third causes plaqueOver contouring in gingival third causes plaque accumulation and gingival inflammation. Ponticaccumulation and gingival inflammation. Pontic design greatly influences gingival health. Ifdesign greatly influences gingival health. If esthetics is a primary concern a spheriodalesthetics is a primary concern a spheriodal Pontic for the posteriors and a modified ridgePontic for the posteriors and a modified ridge lap for the anteriors is ideal.lap for the anteriors is ideal.www.indiandentalacademy.comwww.indiandentalacademy.com
  • The occlusal surfaces should beThe occlusal surfaces should be designed to direct masticatory forcesdesigned to direct masticatory forces along the long axis of the tooth. Thealong the long axis of the tooth. The occlusal table should not be too wide toocclusal table should not be too wide to prevent undue pressure on theprevent undue pressure on the periodontium of the abutment teeth. Aperiodontium of the abutment teeth. A sanitary Pontic is the periodontium’s bestsanitary Pontic is the periodontium’s best friend. Lastly the surface of restorationsfriend. Lastly the surface of restorations should be as smooth as possible to limitshould be as smooth as possible to limit plaque accumulation. But eventually afterplaque accumulation. But eventually after taking all these precautions, patienttaking all these precautions, patient education and motivation towards plaqueeducation and motivation towards plaque control and healthy oral habits is thecontrol and healthy oral habits is the secret of every treatment success.secret of every treatment success. www.indiandentalacademy.comwww.indiandentalacademy.com
  • REVIEW OF LITERATURE:REVIEW OF LITERATURE: 1. Melvin L. Morris 1962 did a study on1. Melvin L. Morris 1962 did a study on artificial crown contours and gingivalartificial crown contours and gingival health. According to him the theory ofhealth. According to him the theory of the artificial bulge in the crown is anthe artificial bulge in the crown is an inaccurate view of gingival coronalinaccurate view of gingival coronal anatomy and physiology. This rationalanatomy and physiology. This rational produces crown that are contoured inproduces crown that are contoured in excess of anything in Nature and Causes,excess of anything in Nature and Causes, rather than prevents, gingivalrather than prevents, gingival inflammation.inflammation. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 2. Sheldon Stein in 1966 did a research on2. Sheldon Stein in 1966 did a research on Pontic ­residual ridge relationship. Pontic designPontic ­residual ridge relationship. Pontic design was the foremost factor in obtainingwas the foremost factor in obtaining inflammatory free pontic ridge relationships.inflammatory free pontic ridge relationships. The ideal design was shown to be a modifiedThe ideal design was shown to be a modified ridge lap in the posterior region and a lapridge lap in the posterior region and a lap facing in the anterior region, with a pin­pointfacing in the anterior region, with a pin­point contact on the facial contiguous slope of thecontact on the facial contiguous slope of the residual ridge. The ideal design should includeresidual ridge. The ideal design should include surface smoothness and a fine finish. Nosurface smoothness and a fine finish. No distinguishing advantage was found withdistinguishing advantage was found with porcelain acrylic resin. A successful artificialporcelain acrylic resin. A successful artificial tooth replacement was characterized by atooth replacement was characterized by a healthy tissue response with the appearance ofhealthy tissue response with the appearance of a lack of contact between the residual ridge anda lack of contact between the residual ridge and under surface of the pontic.under surface of the pontic. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 3. James S. Marcum in 1967 did a study on3. James S. Marcum in 1967 did a study on Crown Marginal depth and gingival tissue 66Crown Marginal depth and gingival tissue 66 gold crowns were placed and finished above,gold crowns were placed and finished above, below and even with the gingival crest in 6below and even with the gingival crest in 6 dogs. The crowns were left in place until thedogs. The crowns were left in place until the dogs were put to death at time intervals one,dogs were put to death at time intervals one, two and three months. Two dogs weretwo and three months. Two dogs were sacrificed at each interval and block specimenssacrificed at each interval and block specimens of the teeth and gingiva were taken at thisof the teeth and gingiva were taken at this time.time. Control specimens of unoperated teeth wereControl specimens of unoperated teeth were also taken. The block specimens werealso taken. The block specimens were decalcified, sectioned stained, histologicallydecalcified, sectioned stained, histologically examined and graded for security ofexamined and graded for security of inflammatory response. 600 metological slidesinflammatory response. 600 metological slides of the tissue sections were graded as havingof the tissue sections were graded as having evidence of none, slight, moderate and severeevidence of none, slight, moderate and severe gingival inflammation.gingival inflammation. www.indiandentalacademy.comwww.indiandentalacademy.com
  • The investigation showed that crownsThe investigation showed that crowns with margins located at a even with thewith margins located at a even with the gingival crest caused the leastgingival crest caused the least inflammatory response. The length ofinflammatory response. The length of time "the restoration was in place hadtime "the restoration was in place had little, if any, effect upon severity oflittle, if any, effect upon severity of degree of inflammation.degree of inflammation. However it appears from results of thisHowever it appears from results of this investigation that crowns with marginsinvestigation that crowns with margins finished even with the gingival crestfinished even with the gingival crest would be least likely to cause gingivalwould be least likely to cause gingival inflammation.inflammation. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 4. Edmand Cauazos in 1968 did a study4. Edmand Cauazos in 1968 did a study on tissue response to fixed partialon tissue response to fixed partial denture pontics. This studydenture pontics. This study demonstrates that the adaptation of ademonstrates that the adaptation of a Pontic "to the ridge or the amount ofPontic "to the ridge or the amount of relief (scraping of the cast) provided inrelief (scraping of the cast) provided in the cast is highly significant and directlythe cast is highly significant and directly proportional to the amount ofproportional to the amount of unfavourable tissue change.unfavourable tissue change. Absolute minimal contact (O.O ­ .25 mmAbsolute minimal contact (O.O ­ .25 mm of cast scraping) produces nochange.of cast scraping) produces nochange. When the cast scraping was increased toWhen the cast scraping was increased to 1 mm, tissue changes were produced1 mm, tissue changes were produced varying from mild inflammation to acutevarying from mild inflammation to acute ulceration.ulceration. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 5. Joseph Clayton in 1970 did a study to compare the5. Joseph Clayton in 1970 did a study to compare the surface roughness, following final finishing andsurface roughness, following final finishing and polishing, of pontics constructed from cast gold, acrylicpolishing, of pontics constructed from cast gold, acrylic resin and glazed porcelain.resin and glazed porcelain.  With a profilometer statistical analysis indicated thatWith a profilometer statistical analysis indicated that the test surfaces of glazed porcelain were significantlythe test surfaces of glazed porcelain were significantly rougher than the polished test surfaces of acrylic resinrougher than the polished test surfaces of acrylic resin or cast gold.or cast gold.  There was no significant difference in surfaceThere was no significant difference in surface roughness between the polished acrylic resin androughness between the polished acrylic resin and polished cast gold sample pontic surfaces. Clinical testpolished cast gold sample pontic surfaces. Clinical test showed that plaque formation occurred on polishedshowed that plaque formation occurred on polished surfaces of pontics constructed of cast gold, acrylicsurfaces of pontics constructed of cast gold, acrylic resin and glazed porcelain. The surfaces of theseresin and glazed porcelain. The surfaces of these pontics were as smooth as the sample pontics whichpontics were as smooth as the sample pontics which were measured in this study.were measured in this study.  Therefore pontic surfaces which are as smooth asTherefore pontic surfaces which are as smooth as possible must be cleaned regularly to prevent thepossible must be cleaned regularly to prevent the accumulation of dental plague.accumulation of dental plague.www.indiandentalacademy.comwww.indiandentalacademy.com
  • 6. Martin Henry Berman in 1973 did a study on6. Martin Henry Berman in 1973 did a study on the interrelationship between completethe interrelationship between complete coverage restoration and the gingival sulcus.coverage restoration and the gingival sulcus. The terminal margin plays an important role inThe terminal margin plays an important role in maintaining gingival health. perio­dontalmaintaining gingival health. perio­dontal disease is minimal with restorations which dodisease is minimal with restorations which do not invade the sulcus, but the caries attacknot invade the sulcus, but the caries attack rate, retention and esthetic requirements mayrate, retention and esthetic requirements may compel entry into the sulcus. The techniquecompel entry into the sulcus. The technique described in this report permits entry into thedescribed in this report permits entry into the sulcus with permanent damaging.sulcus with permanent damaging. 7. Dayton Krajicek in 1973 presented a paper7. Dayton Krajicek in 1973 presented a paper on periodontal consideration in prostheticon periodontal consideration in prosthetic patients. He mentions that Crown contourspatients. He mentions that Crown contours should be adequate to deflect food andshould be adequate to deflect food and contoured gradually so as to permit clearingcontoured gradually so as to permit clearing and to avoid forming a food trap. Marginsand to avoid forming a food trap. Margins should be placed supragingivally as far asshould be placed supragingivally as far as possible.possible. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 8. William A Richter in 1973 did a study8. William A Richter in 1973 did a study inin thethe influence of Crown­margin location on the gingivalinfluence of Crown­margin location on the gingival tissue for 12 cast complete crown. Evaluation weretissue for 12 cast complete crown. Evaluation were made yearly upto three years.To avoid significantmade yearly upto three years.To avoid significant variables, each of the 12 crowns was designed withvariables, each of the 12 crowns was designed with both sub gingival and supra gingival margins on theboth sub gingival and supra gingival margins on the gingival margins of facial surface. A comparison of thegingival margins of facial surface. A comparison of the two margins location using four different methods oftwo margins location using four different methods of evaluation revealed no differenceevaluation revealed no difference inin thethe 1) health of the gingiva,1) health of the gingiva, 2) change2) change inin sulcus depth,sulcus depth, 3) gingival contour and3) gingival contour and 4) plague accumulation.4) plague accumulation.  In view of reported gingival problems near restorationIn view of reported gingival problems near restoration margins, the result of this study suggest that the fitmargins, the result of this study suggest that the fit and finish of full crown restorations may be moreand finish of full crown restorations may be more significant to gingival health than the location of finishsignificant to gingival health than the location of finish lines.lines. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 9.Dominick C. Larato9.Dominick C. Larato inin 1975 did a study1975 did a study on margin extension, brushing andon margin extension, brushing and gingival pocket depth. A total of 111gingival pocket depth. A total of 111 males vetern patients rangingmales vetern patients ranging inin age 21­age 21­ 73 years were selected for the study.73 years were selected for the study. Each had at least one tooth which wasEach had at least one tooth which was restored with a complete cast goldrestored with a complete cast gold veneer crown and a non­restoredveneer crown and a non­restored contralateral tooth with no clinical orcontralateral tooth with no clinical or radiographic evidence of cervical caries.radiographic evidence of cervical caries. All artificial crowns had sub gingivalAll artificial crowns had sub gingival margins. The gingival tissues adjacent tomargins. The gingival tissues adjacent to the crown and unrestored teeth werethe crown and unrestored teeth were probed to determine individual pocketprobed to determine individual pocket depths.depths. www.indiandentalacademy.comwww.indiandentalacademy.com
  • The results are ­The results are ­ 1. The average pocket depth adjacent to non­1. The average pocket depth adjacent to non­ restored teeth was.2.7mm.restored teeth was.2.7mm. The average pocket depth adjacent to teethThe average pocket depth adjacent to teeth having crowns will sub gingival margins washaving crowns will sub gingival margins was 3.4mm.3.4mm. 2.54 non­restored teeth had at least one2.54 non­restored teeth had at least one pocket depth greater than 3mm while 84pocket depth greater than 3mm while 84 crowned teeth had at least one or morecrowned teeth had at least one or more measurements greater than 3 mm.measurements greater than 3 mm. 3. No positive relationship could be found3. No positive relationship could be found between tooth brushing frequency and thebetween tooth brushing frequency and the pocket depth adjacent to teeth restored withpocket depth adjacent to teeth restored with complete cast crowns.complete cast crowns. 4. In non­restored teeth pocket depth4. In non­restored teeth pocket depth increased with reduced frequency of non­increased with reduced frequency of non­ brushing.brushing. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 10.Francisco Palomo and John Pedar in 1976 did10.Francisco Palomo and John Pedar in 1976 did a study on periodontal relationship with regardsa study on periodontal relationship with regards 1. Placement of margins,1. Placement of margins, 2. Marginal fit,2. Marginal fit, 3. Inter dental space and contour of3. Inter dental space and contour of restorations andrestorations and 4. Surface texture4. Surface texture 11. Jan Ruel, Peter Schrussler, Kenneth11. Jan Ruel, Peter Schrussler, Kenneth MalamentMalament inin 1980 did a study on the effect of1980 did a study on the effect of retraction proceduresretraction procedures on the periodontium inon the periodontium in humans. On basis of woundhumans. On basis of wound healing andhealing and gingival recession caused by the cord, electrogingival recession caused by the cord, electro surgery and copper band, the copper band ret­surgery and copper band, the copper band ret­ raction method was the most satisfactory.raction method was the most satisfactory. Retraction methods must be evaluated relativeRetraction methods must be evaluated relative to the impression procedure and fit of theto the impression procedure and fit of the restoration.restoration. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 12. Curtis M. Beker and Wayne Kaldanl12. Curtis M. Beker and Wayne Kaldanl inin 19811981 suggested that crown contours which promotesuggested that crown contours which promote favourable tissue response follow thesefavourable tissue response follow these guidelinesguidelines a) Buccal and lingual contours should be flat,a) Buccal and lingual contours should be flat, b) Embrasure spaces should be kept open,b) Embrasure spaces should be kept open, c) Contact should be high (incisal 1/3 andc) Contact should be high (incisal 1/3 and buccal to central fossa (except between firstbuccal to central fossa (except between first and second molars)and second molars) d) Margins should be supra gingival whereverd) Margins should be supra gingival wherever possible. The pontic design of choice is thepossible. The pontic design of choice is the modified ridge lap for posteriors and ridge lapmodified ridge lap for posteriors and ridge lap for anteriors.for anteriors. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 13) Lee M. Jamson and William Malane13) Lee M. Jamson and William Malane inin 19821982 did a study on crown contours and gingivaldid a study on crown contours and gingival response.The conclusions drawn wereresponse.The conclusions drawn were 1) Deflective contours and or over contouring1) Deflective contours and or over contouring should be avoidedshould be avoided inin the cervical third and thethe cervical third and the inter­proxinial surfaces of tooth restorations.inter­proxinial surfaces of tooth restorations. 2) Over contouring of the inter proximal region2) Over contouring of the inter proximal region isis common and harmful to periodontal health.common and harmful to periodontal health. 3) Adequate tooth reduction at the gingival3) Adequate tooth reduction at the gingival margins and inter proximally provides formargins and inter proximally provides for restoration materials and lessens the potentialrestoration materials and lessens the potential for overcontouringfor overcontouring inin these critical regions.these critical regions. 4) Minimal disruption with the intra crevicular4) Minimal disruption with the intra crevicular space sheering tooth preparation allows a morespace sheering tooth preparation allows a more predictable, favourable periodontal response topredictable, favourable periodontal response to satisfactorily contoured restorations.satisfactorily contoured restorations.www.indiandentalacademy.comwww.indiandentalacademy.com
  • 14) David L Kath14) David L Kath inin 1982 did a study on full crown1982 did a study on full crown restorations and gingival inflammationrestorations and gingival inflammation inin a controlleda controlled population.population. The amount of the crevicular fluid around full crownThe amount of the crevicular fluid around full crown restoration was measured with an instrument torestoration was measured with an instrument to compare the gingival inflammation between restoredcompare the gingival inflammation between restored and unrestored teeth in the same patient. 38 full crownand unrestored teeth in the same patient. 38 full crown restorations were compared to non restored teeth usedrestorations were compared to non restored teeth used as controlsas controls inin 26 patients. The results were as follows:­26 patients. The results were as follows:­ 11.. Full crowns have the potential forFull crowns have the potential for causingcausing gingivalgingival inflammation.inflammation. However, not so in a highly motivatedHowever, not so in a highly motivated patient.patient. 2. Gingival inflammation surrounding full crown resto­2. Gingival inflammation surrounding full crown resto­ rations may be controlled regardless of gingivalrations may be controlled regardless of gingival marginmargin placement when the gingiva is healthy and restorationsplacement when the gingiva is healthy and restorations are adequate and the patient isare adequate and the patient is inin a strict recalla strict recall programme.programme. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 15) John Soumson, Micheal Rewman and Thomas15) John Soumson, Micheal Rewman and Thomas FlemingFleming inin 1991 did a study assessing the efficacy of a1991 did a study assessing the efficacy of a 12%chlorhexidene gluconate rinse on the enhancement12%chlorhexidene gluconate rinse on the enhancement and maintenance of gingival healthand maintenance of gingival health inin patientspatients receivingreceiving fixed prosthesis.fixed prosthesis. Adjunctive use of chlorhexidine withAdjunctive use of chlorhexidine with F.P.D. significantly reduced plague levels and improvedF.P.D. significantly reduced plague levels and improved gingival health compared and controlled patients.gingival health compared and controlled patients. 16) Martin Treelich, Lary C Breeding et al in 1991 did a16) Martin Treelich, Lary C Breeding et al in 1991 did a study testing the effect of fixed partial dentures onstudy testing the effect of fixed partial dentures on hypermobile abutment teeth with substantially reducedhypermobile abutment teeth with substantially reduced levels of periodontal attachment. One abutment toothlevels of periodontal attachment. One abutment tooth and one control (non­abutment) tooth of the same typeand one control (non­abutment) tooth of the same type and periodontal condition were selected for study inand periodontal condition were selected for study in adults.adults. Treatment consisted of periodontal therapy and a 3 or 4Treatment consisted of periodontal therapy and a 3 or 4 unit F.P.D. after which all subjects were placed on aunit F.P.D. after which all subjects were placed on a quarterly maintenance schedule. No differences werequarterly maintenance schedule. No differences were found between the mean baseline and 24 monthfound between the mean baseline and 24 month measures for all dependent variables at test or controlmeasures for all dependent variables at test or control sites.sites. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 17) Martin a Treilhich, Christin Mekrash, Katx17) Martin a Treilhich, Christin Mekrash, Katx et al in 1992 studied the periodontal responseet al in 1992 studied the periodontal response to posterior fixed partial denture relevant withto posterior fixed partial denture relevant with different marginal configurations and locations.different marginal configurations and locations. One posterior proximal site restored with aOne posterior proximal site restored with a clinically acceptable F.P.D. and one matched,clinically acceptable F.P.D. and one matched, unrestored posterior proximal site wereunrestored posterior proximal site were examinedexamined inin 60 patients. Statistical analysis60 patients. Statistical analysis showed that clinically acceptable F.P.D.'s whichshowed that clinically acceptable F.P.D.'s which had clinically detectable deviation from an idealhad clinically detectable deviation from an ideal (flat) retainer/tooth configuration were not(flat) retainer/tooth configuration were not associated with increased probing depths, norassociated with increased probing depths, nor were the sub gingival retainer margins to thewere the sub gingival retainer margins to the supragingival retainer margins. These findingssupragingival retainer margins. These findings suggest that long­term exposure to variationssuggest that long­term exposure to variations of F.P.D. margin configuration and location,of F.P.D. margin configuration and location, within clinically acceptable but less than idealwithin clinically acceptable but less than ideal parameters are not associated with destructionparameters are not associated with destruction of supporting periodontal tissues.of supporting periodontal tissues.www.indiandentalacademy.comwww.indiandentalacademy.com
  • REFERENCESREFERENCES 1. Gengers, Snack, Vagels ­ Over containing in resin1. Gengers, Snack, Vagels ­ Over containing in resin bonded prosthesis Plague accumulation and gingivalbonded prosthesis Plague accumulation and gingival health J.P.D. 59:17:Jan 88.health J.P.D. 59:17:Jan 88. 2. Cuetis Becker, Wayne Kaldaht: Current theories of2. Cuetis Becker, Wayne Kaldaht: Current theories of crown contour margin placement and pontic designcrown contour margin placement and pontic design J.P.D. ­ 45:268:1981.J.P.D. ­ 45:268:1981. 3. Dayton3. Dayton KK Periodontal considerations for prostheticPeriodontal considerations for prosthetic patients J.P.D. 30:15:July73.patients J.P.D. 30:15:July73. 4. DominickC.L. Effect of artificial crown margin4. DominickC.L. Effect of artificial crown margin extensions and tooth brushing frequency on gingivalextensions and tooth brushing frequency on gingival pocket depth.pocket depth. 5. David Koth: Full crown preparation and gingival5. David Koth: Full crown preparation and gingival inflammation in a controlled population.inflammation in a controlled population. J.P.D. 48:681:1982.J.P.D. 48:681:1982. 6. Edmand C: Tissue response to fixed partial denture6. Edmand C: Tissue response to fixed partial denture prosthesis. J.P.D. 23:407:1970.prosthesis. J.P.D. 23:407:1970. 7. Francisco P. John pedar, Periodontal relationship and7. Francisco P. John pedar, Periodontal relationship and F.P.D. J.P.D. 387:36:1976.F.P.D. J.P.D. 387:36:1976. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 8. James Marcum: The effect of crown marginal depth8. James Marcum: The effect of crown marginal depth upon gingival tissues J.P.D. 17:479:1967.upon gingival tissues J.P.D. 17:479:1967. 9. Jon Ruel, Peter S., Keneth M: Effect of retraction9. Jon Ruel, Peter S., Keneth M: Effect of retraction procedures on periodontium in humans J.P.D.procedures on periodontium in humans J.P.D. 44:508:1980.44:508:1980. 10. John Lorensonl6, Micheal N. Gingival enhancement10. John Lorensonl6, Micheal N. Gingival enhancement in F.P.D. 65:100­107:1991.in F.P.D. 65:100­107:1991. 11. Joseph Clayton: Roughness of pontic materials and11. Joseph Clayton: Roughness of pontic materials and dental plague ­ J.P.D. 23:407:1970.dental plague ­ J.P.D. 23:407:1970. 12. Lee M. Jamson,William M: Crown contains and12. Lee M. Jamson,William M: Crown contains and gingival response J.P.D. 47:620:1982.gingival response J.P.D. 47:620:1982. 13. Martin Bermar. The complete coverage restoration13. Martin Bermar. The complete coverage restoration and the gingival sulcus ­ J.P.D.: 29:301:1973.and the gingival sulcus ­ J.P.D.: 29:301:1973. 14. Martin Frelich, Lasy c.: F.P.D. supported by14. Martin Frelich, Lasy c.: F.P.D. supported by periodontally compromised teeth ­ J.P.D.65:607:1991.periodontally compromised teeth ­ J.P.D.65:607:1991. 15. Martin Frelich, C. Riekrash: Periodontal effects of15. Martin Frelich, C. Riekrash: Periodontal effects of F.P.D. retainer margins: configurment and locationF.P.D. retainer margins: configurment and location J.P.D. 67:184:1992.J.P.D. 67:184:1992.www.indiandentalacademy.comwww.indiandentalacademy.com
  • 16. Melvin L. Mories Artificial crown contours16. Melvin L. Mories Artificial crown contours and gingival health J.P.D. 12:l146:Dec.'62.and gingival health J.P.D. 12:l146:Dec.'62. 17. Sheldan Stein: pontic residual ridge17. Sheldan Stein: pontic residual ridge relationship: A report­ J.P.D:16:251:1966.relationship: A report­ J.P.D:16:251:1966. 18. William Richter, Veno: Relationship of crown18. William Richter, Veno: Relationship of crown margin placement to gingival inflammation ­margin placement to gingival inflammation ­ J.P.D.30:156:1973.J.P.D.30:156:1973. 19.Contemporary fixed prosthodontics –19.Contemporary fixed prosthodontics – Rosenstiel.Rosenstiel. 20.Fundamentals of fixed prosthodontics –20.Fundamentals of fixed prosthodontics – Shillingburg.Shillingburg. 21.Clinical periodontology – Carranza21.Clinical periodontology – Carranza 22. Tylman’s theory and practise of fixed22. Tylman’s theory and practise of fixed prosthodontics.prosthodontics. www.indiandentalacademy.comwww.indiandentalacademy.com
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