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Rigid probl/cosmetic dentistry course
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Rigid probl/cosmetic dentistry course


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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  • Stuctural inadequacy and material inadequacy can be overcome by the advances in prosthodontic science. One such advancement is flexible type of dentures
  • The base will not be as flexible as the junction, so the patient comfort during insertion should be taken into account
  • Duplicated model -for pre finishing
  • Set up done on master model
    If try in needed, setup should be done on a wire re-in forced base plate
  • Thinner wax up than acrylic
  • Furnace and melting cylinder should be pre heated
    Flask placed with sprue end up directly under the shaft of the press
  • Resin is more flexible in body temperature
    Green mounted stone usually used for porcelain
  • References
    Maurice N. Stern: Esthetic Restoration for modern dental prosthesis
    Rohdiatoce Soc: Injection Molding of Polyamides
    Delorme J: The present and future of plastic materials Vol IV. The conquests of the plastic materials in medicine and surgery


  • 1. RIGID PROBLEMS,RIGID PROBLEMS, FLEXIBLE SOLUTIONSFLEXIBLE SOLUTIONS INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com
  • 2. IntroductionIntroduction  Prosthetic rehabilitation involvesProsthetic rehabilitation involves compromise incompromise in estheticsesthetics functionfunction  One has to give way for the other inOne has to give way for the other in selective situations because ofselective situations because of structural inadequacy in mouthstructural inadequacy in mouth material inadequacymaterial inadequacy patient’s preferencepatient’s preference affordabilityaffordability www.indiandentalacademy.comwww.indiandentalacademy.com
  • 3.  Partial Dentures are usually anchoredPartial Dentures are usually anchored to abutment teeth by metal claspsto abutment teeth by metal clasps  Conspicuous and estheticallyConspicuous and esthetically unacceptableunacceptable  Induce cariesInduce caries  Destructive on the abutment teethDestructive on the abutment teeth  Trauma to soft tissue and supportingTrauma to soft tissue and supporting bonebone www.indiandentalacademy.comwww.indiandentalacademy.com
  • 4.  In case of full dentures it isIn case of full dentures it is difficult to take advantage of:difficult to take advantage of: Retentive contours of tuberositiesRetentive contours of tuberosities ToriTori Alveolar bosses;Alveolar bosses;  because of the rigidity of methylbecause of the rigidity of methyl methacrylate materialmethacrylate material www.indiandentalacademy.comwww.indiandentalacademy.com
  • 5.  Flexible denture base materials wereFlexible denture base materials were introduced in 1950sintroduced in 1950s  Initially developed as aInitially developed as a fluoropolymer (Teflon type plastic) influoropolymer (Teflon type plastic) in 19621962  Acetal (Resin paraformaldehyde)Acetal (Resin paraformaldehyde) 19711971 www.indiandentalacademy.comwww.indiandentalacademy.com
  • 6.  The material is a pressure injectedThe material is a pressure injected denture base resin containing andenture base resin containing an improved derivative of “nylon” familyimproved derivative of “nylon” family of plastics called Superpolyamides.of plastics called Superpolyamides.  Nylon is a product of the synthesis ofNylon is a product of the synthesis of linear Calcium polyamide andlinear Calcium polyamide and derivatives of coal (fractionalderivatives of coal (fractional distillation)distillation) www.indiandentalacademy.comwww.indiandentalacademy.com
  • 7.  Nylon polyamides -W. Carothers andNylon polyamides -W. Carothers and associates (1931)associates (1931)  The superpolyamides were the resultThe superpolyamides were the result of further research by Fuller,of further research by Fuller, Coffman, Catlin and BakerCoffman, Catlin and Baker www.indiandentalacademy.comwww.indiandentalacademy.com
  • 8. AdvantagesAdvantages  ExceptionallyExceptionally strong, while beingstrong, while being delicatedelicate  Translucency-pickTranslucency-pick up the colour ofup the colour of the underlyingthe underlying tissuetissue  Overall flexibilityOverall flexibility  Stresses on theStresses on the abutment teeth areabutment teeth are completely relievedcompletely relieved D o w n w a r d F o r c e A s s p a c e o p e n s u n d e r s a d d le , r o c k in g m o t io n d is t o r t s c la s p s a n d www.indiandentalacademy.comwww.indiandentalacademy.com
  • 9.  Excellent retention- flexes intoExcellent retention- flexes into retentive position, below undercutsretentive position, below undercuts  Comfort to patient- thin, lightweightComfort to patient- thin, lightweight  No tooth or tissue preparationNo tooth or tissue preparation  Can be used in pediatric patients,Can be used in pediatric patients, cleft patientscleft patients  Can be used as veneers, splintsCan be used as veneers, splints www.indiandentalacademy.comwww.indiandentalacademy.com
  • 10.  No clasp on the toothNo clasp on the tooth surface, but rests onsurface, but rests on gum tissuegum tissue  Massaging effect onMassaging effect on gumsgums  Excellent properties ofExcellent properties of dimensional stability,dimensional stability, volumetric stability,volumetric stability, and elastic memory-and elastic memory- So will maintain itsSo will maintain its relaxed positionrelaxed position  No allergic reactionsNo allergic reactions  Can be used inCan be used in combination withcombination with metallic basesmetallic bases www.indiandentalacademy.comwww.indiandentalacademy.com
  • 11.  Stable and is resistant to polymerStable and is resistant to polymer unzippingunzipping  High creep resistance and fatigueHigh creep resistance and fatigue enduranceendurance  No porosity, no biologic materialNo porosity, no biologic material build up, or odors or stainsbuild up, or odors or stains  Can be reinforced with glass fillersCan be reinforced with glass fillers or fibersor fibers www.indiandentalacademy.comwww.indiandentalacademy.com
  • 12. IndicationsIndications  Few remaining teeth- distalFew remaining teeth- distal extensionextension  Flat ridgeFlat ridge  Transitional applianceTransitional appliance  Root exposuresRoot exposures  Metal/Monomer allergiesMetal/Monomer allergies  Soft splinting, veneersSoft splinting, veneers  Restricted mouth openingRestricted mouth opening www.indiandentalacademy.comwww.indiandentalacademy.com
  • 13. Other UsesOther Uses  Post surgical obturators- Light weightPost surgical obturators- Light weight  Aesthetic correction –gingival maskingAesthetic correction –gingival masking  People in high risk situationsPeople in high risk situations Firefighters- non inflammableFirefighters- non inflammable Police and military personnelPolice and military personnel AthletesAthletes Any person who might be exposed toAny person who might be exposed to harm or injuryharm or injury www.indiandentalacademy.comwww.indiandentalacademy.com
  • 14.  Bruxism splints, night guards,Bruxism splints, night guards,  Bite splintsBite splints  Speech therapy appliancesSpeech therapy appliances  Orthodontic retainersOrthodontic retainers  Sleep apnoea appliancesSleep apnoea appliances  Patients prone to fracture ofPatients prone to fracture of denturesdentures www.indiandentalacademy.comwww.indiandentalacademy.com
  • 15. Contra indicationsContra indications  Mobile teethMobile teeth  <3mm of inter occlusal space<3mm of inter occlusal space  Gingival/periodontal pathologiesGingival/periodontal pathologies  Frequent reliningFrequent relining www.indiandentalacademy.comwww.indiandentalacademy.com
  • 16. Different Superpolyamides available commercially are:  Valplast (Valplast Int. NY)  Proflex (Dental Resources. MN)  Ultraflex (Astron Dental. IL)  Flexite Supreme (Rapid Injection Systems NY)  Soflite  Sunflex  Impak  Protamide  Mailonplast  Superprothenyl  Supolyd www.indiandentalacademy.comwww.indiandentalacademy.com
  • 17. Physical characteristicsPhysical characteristics Methyl methacrylateMethyl methacrylate ValplastValplast  Specific gravity 1.16-1.2 1.04Specific gravity 1.16-1.2 1.04  Water absorption 0.4% 0.4%Water absorption 0.4% 0.4%  Saturation by immersion 1.4% 1.25Saturation by immersion 1.4% 1.25  Young’s Modulus(kg/sq.mm) 280 50-180Young’s Modulus(kg/sq.mm) 280 50-180  Tensile Strength(kg/sq,mm)Tensile Strength(kg/sq,mm) 5-75-7 88  Compressive StrengthCompressive Strength 8.68.6 10.510.5  Bending Strength(kg/sq,mm)Bending Strength(kg/sq,mm) 8.58.5 8-108-10  Vickers hardness 20 14.5Vickers hardness 20 14.5  Impact Strength (kg/sq.mm)Impact Strength (kg/sq.mm) 10.510.5 10-15010-150  Processed softness 275F 437FProcessed softness 275F 437F  Polymerises (in 6hrs) 160F 460FPolymerises (in 6hrs) 160F 460F  CombustionCombustion BurnsBurns Non inflammableNon inflammable  Resistance to acids, basesResistance to acids, bases WeakWeak Very strongVery strong  DiscolorationDiscoloration Possible in timePossible in time NoneNone www.indiandentalacademy.comwww.indiandentalacademy.com
  • 18. Clinical and Lab proceduresClinical and Lab procedures  Normal mucostatic impression with aNormal mucostatic impression with a properly extended custom tray.properly extended custom tray.  Visually survey the cast forVisually survey the cast for designdesign path of insertionpath of insertion estheticsesthetics clasp type and positionclasp type and position  www.indiandentalacademy.comwww.indiandentalacademy.com
  • 19. Clasp Types:Clasp Types:  Wrap around claspWrap around clasp  SpurSpur  High SpurHigh Spur  Anchor or FingerAnchor or Finger  Split claspSplit clasp www.indiandentalacademy.comwww.indiandentalacademy.com
  • 20. Wrap-Around ClaspWrap-Around Clasp  Most Common ClaspMost Common Clasp  Placed on tooth adjacentPlaced on tooth adjacent to replacement.to replacement.  Wrapped around theWrapped around the neck of the tooth inneck of the tooth in harmony with necklineharmony with neckline of second abutmentof second abutment  Free end saddle casesFree end saddle cases www.indiandentalacademy.comwww.indiandentalacademy.com
  • 21. SpurSpur  Placed on the naturalPlaced on the natural tooth next to thetooth next to the replacement, andreplacement, and positioned close to thepositioned close to the neckline in a roughlyneckline in a roughly triangular formtriangular form  High Spur: Used inHigh Spur: Used in cases where abutmentcases where abutment tooth leans to make atooth leans to make a severe undercutsevere undercut  Mainly in posteriorsMainly in posteriors www.indiandentalacademy.comwww.indiandentalacademy.com
  • 22. AnchorAnchor  Also called FingerAlso called Finger  Extend a two toothExtend a two tooth length from thelength from the junction pointjunction point  Mainly on maxillaryMainly on maxillary full dentures infull dentures in labial regionlabial region www.indiandentalacademy.comwww.indiandentalacademy.com
  • 23. Split claspSplit clasp  Used when theUsed when the abutment toothabutment tooth has a wide upperhas a wide upper part, narrowingpart, narrowing toward the necktoward the neck  Resembles RoachResembles Roach claspclasp www.indiandentalacademy.comwww.indiandentalacademy.com
  • 24. Maxillary Wax ReliefMaxillary Wax Relief  Relief Wax placedRelief Wax placed along Buccalalong Buccal PeripheryPeriphery  Necklines of theNecklines of the tissues should betissues should be relieved ifrelieved if periodontal pocketperiodontal pocket or recessionor recession presentpresent www.indiandentalacademy.comwww.indiandentalacademy.com
  • 25. Mandibular Wax ReliefMandibular Wax Relief  Undercut towardUndercut toward periphery must beperiphery must be relievedrelieved  Necklines relievedNecklines relieved www.indiandentalacademy.comwww.indiandentalacademy.com
  • 26. DuplicationDuplication www.indiandentalacademy.comwww.indiandentalacademy.com
  • 27. Set upSet up  Any type of teeth-Any type of teeth- porcelain or acrylicporcelain or acrylic  Retention isRetention is mechanicalmechanical  Twist drills are usedTwist drills are used to prepare diatoricto prepare diatoric holes in teethholes in teeth  Wider drill for centralWider drill for central holehole  Mesial-distalMesial-distal connection with theconnection with the central holecentral hole www.indiandentalacademy.comwww.indiandentalacademy.com
  • 28. Waxing After SetupWaxing After Setup  Proper maximumProper maximum palatal thickness ispalatal thickness is 1.5mm1.5mm  Lingual connectorLingual connector thickness at borderthickness at border is 2mm, thinning tois 2mm, thinning to 1mm at upper1mm at upper edgeedge www.indiandentalacademy.comwww.indiandentalacademy.com
  • 29. Palatal WaxingPalatal Waxing www.indiandentalacademy.comwww.indiandentalacademy.com
  • 30. Buccal WaxingBuccal Waxing Prefabricated forms used www.indiandentalacademy.comwww.indiandentalacademy.com
  • 31. Bottom Half InvestingBottom Half Investing  Inner surface ofInner surface of flask coated withflask coated with petrolatumpetrolatum  Investing stoneInvesting stone should haveshould have minimumminimum compressivecompressive strength of 8000psistrength of 8000psi  Tinfoil substitute asTinfoil substitute as separating mediumseparating medium www.indiandentalacademy.comwww.indiandentalacademy.com
  • 32. SpruingSpruing  Two sprues fromTwo sprues from the centre of thethe centre of the sprue opening,sprue opening, curving slightly tocurving slightly to meet the posteriormeet the posterior of the waxedof the waxed partialpartial www.indiandentalacademy.comwww.indiandentalacademy.com
  • 33. Top Half Investing and Boiling outTop Half Investing and Boiling out •Standard die stone may alsoStandard die stone may also be used- for easierbe used- for easier deflaskingdeflasking •Boiling water bath for 6minBoiling water bath for 6min •Bench coolBench coolwww.indiandentalacademy.comwww.indiandentalacademy.com
  • 34. ProcessingProcessing www.indiandentalacademy.comwww.indiandentalacademy.com
  • 35. After ProcessingAfter Processing Sprues cut off by fiber cutterSprues cut off by fiber cutterwww.indiandentalacademy.comwww.indiandentalacademy.com
  • 36. Pre-FinishingPre-Finishing Trimmer Dark grinding wheels www.indiandentalacademy.comwww.indiandentalacademy.com
  • 37. Fitting and RubberizingFitting and Rubberizing Brown rubber wheels for pre-polishing Vulcanite burs www.indiandentalacademy.comwww.indiandentalacademy.com
  • 38. PolishingPolishing PumicePumice Brown TripoliBrown Tripoli www.indiandentalacademy.comwww.indiandentalacademy.com
  • 39. AdjustmentsAdjustments  Minor adjustments- heating the claspMinor adjustments- heating the clasp in very hot water -bending severelyin very hot water -bending severely in the needed direction.in the needed direction.  Grinding should be done as a lastGrinding should be done as a last resort.resort.  Use a Standard Green mountedUse a Standard Green mounted stone to adjust. 20K to 30K rotationstone to adjust. 20K to 30K rotation and constant motionand constant motion www.indiandentalacademy.comwww.indiandentalacademy.com
  • 40. CorrectionsCorrections  Small Additions- hot air weldingSmall Additions- hot air welding  Large additions –injection. Wax withLarge additions –injection. Wax with new section on duplicate model tonew section on duplicate model to original partial. Bonding site shouldoriginal partial. Bonding site should be acid etched.be acid etched.  Relining- Rewaxing and processingRelining- Rewaxing and processing on a duplicated model with a puttyon a duplicated model with a putty indexindex www.indiandentalacademy.comwww.indiandentalacademy.com
  • 41. ConclusionConclusion  The challenge of conventional RPD designThe challenge of conventional RPD design is to balance the requirements of retentionis to balance the requirements of retention and support while minimizing damage toand support while minimizing damage to natural dentition and the supporting ridge.natural dentition and the supporting ridge.  The flexible denture approach is toThe flexible denture approach is to address the requirement of retention andaddress the requirement of retention and support by leveraging flexible basesupport by leveraging flexible base properties with simple designs.properties with simple designs. www.indiandentalacademy.comwww.indiandentalacademy.com
  • 42. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com