OCCLUSALOCCLUSAL
CONSIDERATIONS INCONSIDERATIONS IN
REMOVABLEREMOVABLE
PROSTHODONTICSPROSTHODONTICS
INDIAN DENTAL ACADEMY
...
IntroductionIntroduction
Good occlusal practice for removable denturesGood occlusal practice for removable dentures
is ver...
Occlusion for complete dentures, however, has threeOcclusion for complete dentures, however, has three
significant differe...
PARTIAL DENTURES:PARTIAL DENTURES:
Occlusion:Occlusion:
The usual goal of partial denture treatmentThe usual goal of parti...
Treatment planning for partial denturesTreatment planning for partial dentures
When replacing missing teeth, it is of evid...
Clinical stagesClinical stages
Recording centric jaw relationRecording centric jaw relation
The working casts also may be ...
Insertion – occlusal correctionInsertion – occlusal correction
Minor interferences are often present, as in completeMinor ...
When maxillary and mandibular dentures are beingWhen maxillary and mandibular dentures are being
inserted, each denture mu...
COMPLETE DENTURES:COMPLETE DENTURES:
Occlusion:Occlusion:
In a detailed overview of the literature ofIn a detailed overvie...
Patient satisfaction with dentures does notPatient satisfaction with dentures does not
correlate closely with technical qu...
Recommended occlusion for complete denturesRecommended occlusion for complete dentures
Recommended practice is to develop ...
Occlusal vertical dimension(OVD)Occlusal vertical dimension(OVD)
There is much evidence to show that it is possible toTher...
Perhaps the most commonly used method hasPerhaps the most commonly used method has
been to determine postural jaw position...
The clinician must register an OVD and pass thatThe clinician must register an OVD and pass that
information to the techni...
Artificial teeth:Artificial teeth: Artificial teeth are made fromArtificial teeth are made from
either acrylic resin or po...
Zero-degree teeth (flat-cusped, cuspless) – areZero-degree teeth (flat-cusped, cuspless) – are
said to be indicated for ca...
Balanced occlusionBalanced occlusion
Balanced occlusion refers to occlusion withBalanced occlusion refers to occlusion wit...
The five determinants or variables affecting occlusalThe five determinants or variables affecting occlusal
contacts are kn...
The extent to which the balanced occlusion/articulationThe extent to which the balanced occlusion/articulation
developed o...
Lingualised occlusion:Lingualised occlusion:
In conventional artificial tooth arrangement theIn conventional artificial to...
Clinical considerations relating to occlusion:Clinical considerations relating to occlusion:
Determining occlusal vertical...
Recording centric jaw relationRecording centric jaw relation ::
Centric jaw relationship is a reproducibleCentric jaw rela...
Selecting an articulator for complete dentureSelecting an articulator for complete denture
prosthodontics:prosthodontics:
...
Split-cast techniqueSplit-cast technique
As the acrylic resin cures during theAs the acrylic resin cures during the
proces...
Occlusal correction at insertionOcclusal correction at insertion
There are often occlusal interferences at theThere are of...
Selective grindingSelective grinding
Minor errors are commonly detected with theMinor errors are commonly detected with th...
There are two stages to chairside occlusal adjustment:There are two stages to chairside occlusal adjustment:
The first obj...
The second objective of occlusal adjustment isThe second objective of occlusal adjustment is
to obtain a balanced occlusio...
If there is misalignment of cusp–fossaIf there is misalignment of cusp–fossa
relationships, the cusps and their opposingre...
Precentric (check) recordPrecentric (check) record more extensivemore extensive
errors can be eliminated using a precentri...
Rerecording CR:Rerecording CR: Occasionally the occlusalOccasionally the occlusal
errors may be so large that chairsideerr...
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Transcript of "Occlusal considerations in rpd/ orthodontic seminars"

  1. 1. OCCLUSALOCCLUSAL CONSIDERATIONS INCONSIDERATIONS IN REMOVABLEREMOVABLE PROSTHODONTICSPROSTHODONTICS INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com
  2. 2. IntroductionIntroduction Good occlusal practice for removable denturesGood occlusal practice for removable dentures is very similar to that described for fixedis very similar to that described for fixed prostheses.prostheses. Partial dentures should not transmit excessivePartial dentures should not transmit excessive forces to supporting tissues nor interfere inforces to supporting tissues nor interfere in intercuspal position or in functionalintercuspal position or in functional movements. The occlusal form is usuallymovements. The occlusal form is usually confirmative with the natural teeth.confirmative with the natural teeth. Occasionally a reconstructive approach usingOccasionally a reconstructive approach using onlays is used.onlays is used. www.indiandentalacademy.comwww.indiandentalacademy.com
  3. 3. Occlusion for complete dentures, however, has threeOcclusion for complete dentures, however, has three significant differences:significant differences: 1) The absence of natural teeth in edentulous patients1) The absence of natural teeth in edentulous patients may present significant difficulties in determining anmay present significant difficulties in determining an acceptable occlusal vertical dimension (OVD).acceptable occlusal vertical dimension (OVD). 2) Complete denture occlusion is always a2) Complete denture occlusion is always a ‘reorganised’occlusion.‘reorganised’occlusion. 3) Absence of teeth produces problems of denture3) Absence of teeth produces problems of denture stability (resistance to displacement by lateral forces),stability (resistance to displacement by lateral forces), particularly of the mandibular complete denture. Theparticularly of the mandibular complete denture. The stability of complete dentures is optimised by astability of complete dentures is optimised by a balanced occlusionbalanced occlusion.. www.indiandentalacademy.comwww.indiandentalacademy.com
  4. 4. PARTIAL DENTURES:PARTIAL DENTURES: Occlusion:Occlusion: The usual goal of partial denture treatmentThe usual goal of partial denture treatment (in respect of the occlusion) is to position the(in respect of the occlusion) is to position the artificial teeth so that there is even contactartificial teeth so that there is even contact and maximum intercuspation (MI) in theand maximum intercuspation (MI) in the intercuspal position (ICP). For moreintercuspal position (ICP). For more extensive partial dentures, such as bilateralextensive partial dentures, such as bilateral distal extension saddle dentures, the aimdistal extension saddle dentures, the aim might also be to achieve a balancedmight also be to achieve a balanced occlusion.occlusion. www.indiandentalacademy.comwww.indiandentalacademy.com
  5. 5. Treatment planning for partial denturesTreatment planning for partial dentures When replacing missing teeth, it is of evidentWhen replacing missing teeth, it is of evident importance that treatment is based on aimportance that treatment is based on a comprehensive treatment plan. The treatmentcomprehensive treatment plan. The treatment plan must be derived from a careful history,plan must be derived from a careful history, examination and the use of appropriate specialexamination and the use of appropriate special investigations. For the partially dentate patient,investigations. For the partially dentate patient, special investigations include radiographs,special investigations include radiographs, tooth vitality tests and usually articulated,tooth vitality tests and usually articulated, surveyed study casts. And include a detailedsurveyed study casts. And include a detailed design of any prosthesis.design of any prosthesis. www.indiandentalacademy.comwww.indiandentalacademy.com
  6. 6. Clinical stagesClinical stages Recording centric jaw relationRecording centric jaw relation The working casts also may be articulated without anThe working casts also may be articulated without an occlusal record if centric occlusion (CO) is coincidentocclusal record if centric occlusion (CO) is coincident with CR and if there are sufficient teeth to providewith CR and if there are sufficient teeth to provide stable ICP of the casts, if there are insufficient teeth,stable ICP of the casts, if there are insufficient teeth, wax occlusal rims are used. The wax may be placedwax occlusal rims are used. The wax may be placed on shellac or acrylic base plates, or more commonlyon shellac or acrylic base plates, or more commonly on the metal framework. If the wax rims are to beon the metal framework. If the wax rims are to be placed on the framework it is important to ensureplaced on the framework it is important to ensure beforehand that the framework fits accurately andbeforehand that the framework fits accurately and does not interfere with the occlusion in retrudeddoes not interfere with the occlusion in retruded contact position (RCP, ICP) or in lateral excursions.contact position (RCP, ICP) or in lateral excursions. www.indiandentalacademy.comwww.indiandentalacademy.com
  7. 7. Insertion – occlusal correctionInsertion – occlusal correction Minor interferences are often present, as in completeMinor interferences are often present, as in complete dentures, due to previous clinical or laboratory errors.dentures, due to previous clinical or laboratory errors. The dentures must be adjusted so that the naturalThe dentures must be adjusted so that the natural teeth meet in precisely the same way both with andteeth meet in precisely the same way both with and without the Dentures in place. Often chair sidewithout the Dentures in place. Often chair side adjustment by selective grinding is Sufficient. Marksadjustment by selective grinding is Sufficient. Marks produced by articulating paper must be interpretedproduced by articulating paper must be interpreted with caution, by visual confirmation and by askingwith caution, by visual confirmation and by asking the patient for his or her perception of how the teeththe patient for his or her perception of how the teeth contact. The patient should be asked whether thecontact. The patient should be asked whether the teeth contact evenly or meet on one side first. Ifteeth contact evenly or meet on one side first. If aware of a premature contact, can the patient feelaware of a premature contact, can the patient feel which tooth or teeth meet first. Again, thiswhich tooth or teeth meet first. Again, this information must be used with caution.information must be used with caution. www.indiandentalacademy.comwww.indiandentalacademy.com
  8. 8. When maxillary and mandibular dentures are beingWhen maxillary and mandibular dentures are being inserted, each denture must be checked and correctedinserted, each denture must be checked and corrected separately. A final correction is done with bothseparately. A final correction is done with both dentures in place. Very occasionally the occlusaldentures in place. Very occasionally the occlusal errors are so large that chair side correction is noterrors are so large that chair side correction is not possible. In these cases, the artificial teeth causing thepossible. In these cases, the artificial teeth causing the interferences should be ground off. Wax can be placedinterferences should be ground off. Wax can be placed on the base in those regions and CR can be rerecorded.on the base in those regions and CR can be rerecorded. If the denture has been returned to the clinic with theIf the denture has been returned to the clinic with the casts, a new occlusal record can be taken, the castscasts, a new occlusal record can be taken, the casts remounted and the occlusion corrected in theremounted and the occlusion corrected in the laboratory. Otherwise an overall impression should belaboratory. Otherwise an overall impression should be taken with the denture(s) in place. The impressionstaken with the denture(s) in place. The impressions should be cast and the dentures rearticulated, reset andshould be cast and the dentures rearticulated, reset and retried.retried. www.indiandentalacademy.comwww.indiandentalacademy.com
  9. 9. COMPLETE DENTURES:COMPLETE DENTURES: Occlusion:Occlusion: In a detailed overview of the literature ofIn a detailed overview of the literature of occlusal considerations in completeocclusal considerations in complete dentures, Palla (1997) noted that patientsdentures, Palla (1997) noted that patients satisfaction with complete dentures is asatisfaction with complete dentures is a complex phenomenon and that thecomplex phenomenon and that the occlusion plays only a minor part. Further,occlusion plays only a minor part. Further, there is little evidence to support of tooththere is little evidence to support of tooth form, tooth arrangement or occlusalform, tooth arrangement or occlusal schemes.schemes. www.indiandentalacademy.comwww.indiandentalacademy.com
  10. 10. Patient satisfaction with dentures does notPatient satisfaction with dentures does not correlate closely with technical quality. Forcorrelate closely with technical quality. For example, patients with greatly decreasedexample, patients with greatly decreased vertical dimension and severely worn occlusalvertical dimension and severely worn occlusal surfaces may have no complaint about theirsurfaces may have no complaint about their dentures. Indeed they may be unable to adaptdentures. Indeed they may be unable to adapt to new ‘better’ dentures. Nevertheless, it isto new ‘better’ dentures. Nevertheless, it is important to understand the principles ofimportant to understand the principles of occlusion related to removable prostheses inocclusion related to removable prostheses in order to try to provide optimum treatment bestorder to try to provide optimum treatment best suited to each individual. The clinician shouldsuited to each individual. The clinician should have a clear picture of the occlusion that he orhave a clear picture of the occlusion that he or she is trying to achieve for each patient.she is trying to achieve for each patient. www.indiandentalacademy.comwww.indiandentalacademy.com
  11. 11. Recommended occlusion for complete denturesRecommended occlusion for complete dentures Recommended practice is to develop maximumRecommended practice is to develop maximum intercuspation of complete dentures to coincide withintercuspation of complete dentures to coincide with CR at an acceptable OVD. Failure to achieve that canCR at an acceptable OVD. Failure to achieve that can lead to intolerance, usually because of instability oflead to intolerance, usually because of instability of the denturesthe dentures or because of pain of the alveolaror because of pain of the alveolar mucosa as a result of uneven load distribution andmucosa as a result of uneven load distribution and high stress concentrations.high stress concentrations. It is also recommended that aIt is also recommended that a balanced occlusionbalanced occlusion (i.e.(i.e. harmonious contacts between maxillary andharmonious contacts between maxillary and mandibular teeth in all excursive movements) ismandibular teeth in all excursive movements) is provided in order to help give occlusal stability.provided in order to help give occlusal stability. www.indiandentalacademy.comwww.indiandentalacademy.com
  12. 12. Occlusal vertical dimension(OVD)Occlusal vertical dimension(OVD) There is much evidence to show that it is possible toThere is much evidence to show that it is possible to increase OVD without adverse consequences, in bothincrease OVD without adverse consequences, in both the natural dentition and in complete dentures (Pallathe natural dentition and in complete dentures (Palla 1997).1997). There are limits to an individual’s ability to adapt toThere are limits to an individual’s ability to adapt to opening or closing an OVD. The OVD has a greatopening or closing an OVD. The OVD has a great influence on facial appearance. Complete denturesinfluence on facial appearance. Complete dentures with insufficient freeway space cause difficulties withwith insufficient freeway space cause difficulties with speech and may result in pain beneath the denture. Itspeech and may result in pain beneath the denture. It can be very difficult to determine an acceptablecan be very difficult to determine an acceptable correct OVD once it is lost and many methods havecorrect OVD once it is lost and many methods have been developed to help establish OVDbeen developed to help establish OVD.. www.indiandentalacademy.comwww.indiandentalacademy.com
  13. 13. Perhaps the most commonly used method hasPerhaps the most commonly used method has been to determine postural jaw position (PJP,been to determine postural jaw position (PJP, ‘resting vertical dimension’). OVD is then‘resting vertical dimension’). OVD is then established 2–4 mm less than PJP. PJP is notestablished 2–4 mm less than PJP. PJP is not constant, however, and methods used toconstant, however, and methods used to measure it generally have poor reproducibility.measure it generally have poor reproducibility. It varies with, among other things, headIt varies with, among other things, head posture, the instructions given to the patient toposture, the instructions given to the patient to achieve ‘rest’ and with time. It is also knownachieve ‘rest’ and with time. It is also known that altering an OVD will lead to thethat altering an OVD will lead to the establishment of a new PJP.establishment of a new PJP. www.indiandentalacademy.comwww.indiandentalacademy.com
  14. 14. The clinician must register an OVD and pass thatThe clinician must register an OVD and pass that information to the technician. Experienced cliniciansinformation to the technician. Experienced clinicians usually rely on a combination of methods at theusually rely on a combination of methods at the registration stage; for example, measuring PJP,registration stage; for example, measuring PJP, observing patient appearance at selected OVD andobserving patient appearance at selected OVD and measuring the OVD of previously satisfactorymeasuring the OVD of previously satisfactory dentures. Clinicians must then try to verify thedentures. Clinicians must then try to verify the dimension at try-in stage, again by the use of adimension at try-in stage, again by the use of a similar combination of methods. It is usually possiblesimilar combination of methods. It is usually possible to provide a patient with new dentures with a greaterto provide a patient with new dentures with a greater OVD than that of the previous old dentures. It is wiseOVD than that of the previous old dentures. It is wise to test any increase by the progressive addition ofto test any increase by the progressive addition of autopolymerising acrylic to the occlusal surfaces ofautopolymerising acrylic to the occlusal surfaces of the artificial teeth of the old dentures.the artificial teeth of the old dentures. www.indiandentalacademy.comwww.indiandentalacademy.com
  15. 15. Artificial teeth:Artificial teeth: Artificial teeth are made fromArtificial teeth are made from either acrylic resin or porcelain. The quality ofeither acrylic resin or porcelain. The quality of acrylic teeth has improved greatly in recentacrylic teeth has improved greatly in recent years and porcelain teeth are no longeryears and porcelain teeth are no longer commonly used. Two types of posterior cuspcommonly used. Two types of posterior cusp form are produced by manufacturers ofform are produced by manufacturers of artificial teethartificial teeth •• Anatomical teeth – may have different cuspalAnatomical teeth – may have different cuspal angulations, e.g. 20°, 30° or 40° cuspal angle;angulations, e.g. 20°, 30° or 40° cuspal angle; 20° cuspal angle teeth are commonly used for20° cuspal angle teeth are commonly used for complete denturescomplete dentures.. www.indiandentalacademy.comwww.indiandentalacademy.com
  16. 16. Zero-degree teeth (flat-cusped, cuspless) – areZero-degree teeth (flat-cusped, cuspless) – are said to be indicated for cases with flat alveolarsaid to be indicated for cases with flat alveolar ridges or where there is great difficultyridges or where there is great difficulty recording CR.recording CR. Research has not provided evidence to supportResearch has not provided evidence to support commonly held views on advantages andcommonly held views on advantages and disadvantages of artificial tooth form. Fordisadvantages of artificial tooth form. For example, while it is possible that selection ofexample, while it is possible that selection of artificial posterior teeth, such as cusped ratherartificial posterior teeth, such as cusped rather than cuspless, may have a marginal effect onthan cuspless, may have a marginal effect on chewing efficiency, other factors, in particularchewing efficiency, other factors, in particular retention and stability of the dentures, have farretention and stability of the dentures, have far more effect.more effect. www.indiandentalacademy.comwww.indiandentalacademy.com
  17. 17. Balanced occlusionBalanced occlusion Balanced occlusion refers to occlusion withBalanced occlusion refers to occlusion with simultaneous contacts of the occlusal surfacesimultaneous contacts of the occlusal surface of all or some of the teeth on both sides of theof all or some of the teeth on both sides of the arch in all mandibular positions. A balancedarch in all mandibular positions. A balanced occlusion is developed on the articulator.occlusion is developed on the articulator. www.indiandentalacademy.comwww.indiandentalacademy.com
  18. 18. The five determinants or variables affecting occlusalThe five determinants or variables affecting occlusal contacts are known as Hanau’s quint:contacts are known as Hanau’s quint: 1.1. Orientation of occlusal planeOrientation of occlusal plane. Average-value. Average-value articulators have preset distances between thearticulators have preset distances between the condylar components and the incisal tips. Thecondylar components and the incisal tips. The orientation of the occlusal plane is determined by theorientation of the occlusal plane is determined by the clinician when trimming the upper occlusal rim.clinician when trimming the upper occlusal rim. 2.2. Condylar guidanceCondylar guidance. Condylar angles of average value. Condylar angles of average value articulators are also preset, usually at 30°.articulators are also preset, usually at 30°. 3.3. Incisal guidance.Incisal guidance. Incisal guidance is commonly setIncisal guidance is commonly set arbitrarily at 10 or 15°.arbitrarily at 10 or 15°. 4.4. Cuspal angle.Cuspal angle. The cuspal angles of the artificial teethThe cuspal angles of the artificial teeth are produced by the manufacturer.are produced by the manufacturer. 5.5. Compensating curveCompensating curve. The dental technician sets the. The dental technician sets the artificial teeth with a compensating curve that allowsartificial teeth with a compensating curve that allows for a balanced occlusion.for a balanced occlusion.www.indiandentalacademy.comwww.indiandentalacademy.com
  19. 19. The extent to which the balanced occlusion/articulationThe extent to which the balanced occlusion/articulation developed on an articulator will be present in thedeveloped on an articulator will be present in the mouth will depend on the accuracy of the centric jawmouth will depend on the accuracy of the centric jaw registration used to articulate the casts. It will alsoregistration used to articulate the casts. It will also depend on the degree to which the settings of thedepend on the degree to which the settings of the articulator replicate the corresponding parameters ofarticulator replicate the corresponding parameters of the patient’s jaws. Use of a semi adjustable articulatorthe patient’s jaws. Use of a semi adjustable articulator and a facebow record, and lateral and protrusiveand a facebow record, and lateral and protrusive records to set condylar angles, will more accuratelyrecords to set condylar angles, will more accurately replicate the mouth than an average value articulator.replicate the mouth than an average value articulator. In most cases when inserting dentures it will beIn most cases when inserting dentures it will be necessary to adjust the occlusion, for example usingnecessary to adjust the occlusion, for example using articulating foil in the mouth and specific occlusalarticulating foil in the mouth and specific occlusal adjustment at the chairside, in order to produce aadjustment at the chairside, in order to produce a balanced occlusion.balanced occlusion. www.indiandentalacademy.comwww.indiandentalacademy.com
  20. 20. Lingualised occlusion:Lingualised occlusion: In conventional artificial tooth arrangement theIn conventional artificial tooth arrangement the lower artificial buccal cusps occlude with thelower artificial buccal cusps occlude with the fossae opposing upper teeth. The upper palatalfossae opposing upper teeth. The upper palatal cusps occlude with the fossae of the lowercusps occlude with the fossae of the lower teeth. In a so-called lingualised occlusion, theteeth. In a so-called lingualised occlusion, the lower buccal cusps are cut back so that there islower buccal cusps are cut back so that there is only contact on the upper palatal cusps. Thisonly contact on the upper palatal cusps. This scheme allows the ease of obtaining ascheme allows the ease of obtaining a balanced occlusion comparable with the use ofbalanced occlusion comparable with the use of zero cusped teeth, together with the advantagezero cusped teeth, together with the advantage of retaining posterior tooth cusp form andof retaining posterior tooth cusp form and therefore a pleasing appearancetherefore a pleasing appearance.. www.indiandentalacademy.comwww.indiandentalacademy.com
  21. 21. Clinical considerations relating to occlusion:Clinical considerations relating to occlusion: Determining occlusal vertical dimension:Determining occlusal vertical dimension: As described above, determining an acceptableAs described above, determining an acceptable OVD can be difficult. Experienced cliniciansOVD can be difficult. Experienced clinicians usually rely on a combination of methods atusually rely on a combination of methods at the registration.the registration. www.indiandentalacademy.comwww.indiandentalacademy.com
  22. 22. Recording centric jaw relationRecording centric jaw relation :: Centric jaw relationship is a reproducibleCentric jaw relationship is a reproducible position that is used to articulate edentulousposition that is used to articulate edentulous casts. The artificial teeth are set so thatcasts. The artificial teeth are set so that maximum intercuspation occurs at thismaximum intercuspation occurs at this position for complete dentures. Many differentposition for complete dentures. Many different methods have been described for recordingmethods have been described for recording CR. They may be classified as static orCR. They may be classified as static or functional. Most methods are capable offunctional. Most methods are capable of giving accurate results but functionalgiving accurate results but functional techniques such as ‘chew-in’ techniques aretechniques such as ‘chew-in’ techniques are not commonly used. The most common is thenot commonly used. The most common is the use of interocclusal wax occlusal rims.use of interocclusal wax occlusal rims. www.indiandentalacademy.comwww.indiandentalacademy.com
  23. 23. Selecting an articulator for complete dentureSelecting an articulator for complete denture prosthodontics:prosthodontics: As discussed previously, an average valueAs discussed previously, an average value articulator can be used with good results.articulator can be used with good results. However, in order to produce dentures with aHowever, in order to produce dentures with a balanced occlusion/articulation that shouldbalanced occlusion/articulation that should need minimal adjustment at insertion, aneed minimal adjustment at insertion, a semiadjustable articulator together with thesemiadjustable articulator together with the use of a facebow, and lateral and protrusiveuse of a facebow, and lateral and protrusive transfer records, should be considered.transfer records, should be considered. www.indiandentalacademy.comwww.indiandentalacademy.com
  24. 24. Split-cast techniqueSplit-cast technique As the acrylic resin cures during theAs the acrylic resin cures during the processing of complete dentures, the artificialprocessing of complete dentures, the artificial teeth can move slightly in the moulds. A split-teeth can move slightly in the moulds. A split- cast technique is recommended to relocatecast technique is recommended to relocate complete dentures on the articulator followingcomplete dentures on the articulator following processing. This allows any minor occlusalprocessing. This allows any minor occlusal errors that have occurred during processing toerrors that have occurred during processing to be corrected.be corrected. www.indiandentalacademy.comwww.indiandentalacademy.com
  25. 25. Occlusal correction at insertionOcclusal correction at insertion There are often occlusal interferences at theThere are often occlusal interferences at the insertion stage as a result of inaccuracy ofinsertion stage as a result of inaccuracy of recording CR and limitations imposed by therecording CR and limitations imposed by the articulator. Three methods are used to correctarticulator. Three methods are used to correct the occlusion: selective grinding, precentricthe occlusion: selective grinding, precentric (check)record and rerecording CR.(check)record and rerecording CR. www.indiandentalacademy.comwww.indiandentalacademy.com
  26. 26. Selective grindingSelective grinding Minor errors are commonly detected with theMinor errors are commonly detected with the use of articulating foil and corrected at theuse of articulating foil and corrected at the chair side. Because of the inherent instabilitychair side. Because of the inherent instability of the denture bases, caution must be usedof the denture bases, caution must be used when interpreting the marks made by thewhen interpreting the marks made by the paper. Some clinicians consider that anypaper. Some clinicians consider that any adjustments should only be made with the useadjustments should only be made with the use of a precentric (check) record, as describedof a precentric (check) record, as described below.below. www.indiandentalacademy.comwww.indiandentalacademy.com
  27. 27. There are two stages to chairside occlusal adjustment:There are two stages to chairside occlusal adjustment: The first objective is to ensure maximumThe first objective is to ensure maximum intercuspation occurs in CR. Two possible errorsintercuspation occurs in CR. Two possible errors may be present. One error occurs when the cusp–may be present. One error occurs when the cusp– fossa relationships are correct but one or more teethfossa relationships are correct but one or more teeth meet prematurely. To correct this type of error, themeet prematurely. To correct this type of error, the opposing fossae should be deepened until there isopposing fossae should be deepened until there is even bilateral contact. The other error is when there iseven bilateral contact. The other error is when there is misalignment of cusp–fossa relationships. This ismisalignment of cusp–fossa relationships. This is corrected by first grinding mesial and distal slopes ofcorrected by first grinding mesial and distal slopes of opposing teeth, until cusp–fossa realignment isopposing teeth, until cusp–fossa realignment is regained. The opposing fossae can then be deepenedregained. The opposing fossae can then be deepened until even contact is established.until even contact is established. www.indiandentalacademy.comwww.indiandentalacademy.com
  28. 28. The second objective of occlusal adjustment isThe second objective of occlusal adjustment is to obtain a balanced occlusion. To readilyto obtain a balanced occlusion. To readily achieve this the BULL (buccal upper, lingualachieve this the BULL (buccal upper, lingual lower) rule is recommended. It is thelower) rule is recommended. It is the contacting surfaces of these cusps (the palatalcontacting surfaces of these cusps (the palatal surface of the upper buccal cusps and thesurface of the upper buccal cusps and the buccal surfaces of the lower lingual cusps) thatbuccal surfaces of the lower lingual cusps) that are ground, rather than the cusp tipsare ground, rather than the cusp tips www.indiandentalacademy.comwww.indiandentalacademy.com
  29. 29. If there is misalignment of cusp–fossaIf there is misalignment of cusp–fossa relationships, the cusps and their opposingrelationships, the cusps and their opposing embrasures should be adjusted by grindingembrasures should be adjusted by grinding mesial and distal cusp slopes of opposingmesial and distal cusp slopes of opposing teeth. The adjustment process should beteeth. The adjustment process should be continued until balanced occlusion is achievedcontinued until balanced occlusion is achieved www.indiandentalacademy.comwww.indiandentalacademy.com
  30. 30. Precentric (check) recordPrecentric (check) record more extensivemore extensive errors can be eliminated using a precentricerrors can be eliminated using a precentric record. To do this, two layers of warmrecord. To do this, two layers of warm softened baseplate wax are placed on the lowersoftened baseplate wax are placed on the lower premolars and molars. The patient ispremolars and molars. The patient is instructed/guided to close into the wax (but notinstructed/guided to close into the wax (but not to close into tooth contact) in the retrudedto close into tooth contact) in the retruded position. The dentures are then articulatedposition. The dentures are then articulated using this record and any errors are removed .using this record and any errors are removed . When the dentures are inserted, minor errorsWhen the dentures are inserted, minor errors can be readily corrected as described.can be readily corrected as described. www.indiandentalacademy.comwww.indiandentalacademy.com
  31. 31. Rerecording CR:Rerecording CR: Occasionally the occlusalOccasionally the occlusal errors may be so large that chairsideerrors may be so large that chairside adjustment or even a check record could notadjustment or even a check record could not correct the problem. In these cases, if thecorrect the problem. In these cases, if the appearance of the anterior teeth is satisfactory,appearance of the anterior teeth is satisfactory, the posterior teeth should be ground off, waxthe posterior teeth should be ground off, wax can be placed on the base in those regions andcan be placed on the base in those regions and CR can be rerecorded. The dentures can thenCR can be rerecorded. The dentures can then be rearticulated, teeth reset and a denture try-inbe rearticulated, teeth reset and a denture try-in is repeated.is repeated. www.indiandentalacademy.comwww.indiandentalacademy.com
  32. 32. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com

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