Occlusion in removable partial Denture
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The document discusses the principles and procedures related to occlusion in removable partial dentures (RPD), emphasizing the importance of balancing occlusal contacts to distribute workload evenly to the underlying bone. It covers occlusal analysis, equilibration techniques, and various materials and methods for recording centric relation, providing guidelines for achieving balanced and functional occlusion. Additionally, it highlights the roles of different occlusal schemes like canine protected occlusion and group function in preventing stresses on teeth and supporting structures.
Occlusion in removable partial Denture
- 1. www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad OCCLUSION IN REMOVABLE PARTIAL DENTURE
- 2. INTRODUCTION • Occlusion is dentistry • Dentistry is occlusion • Occlusion is the medium of dentistry • “Always talking about it, but never doing anything about it” Mark Twains www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 3. Unresolved controversies of occlusion are due to Much knowledge is based upon empirical rather than scientific information Tissue tolerance of each individual is very broad Tremendous variable factors www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 4. •The principle problem in RPD appears to be •The equalization of supporting properties of partially edentulous mouth, so that the occlusal work load when transmitted to the underlying bone is evenly distributed as possible between yielding and nonyielding support •Yielding support – teeth and PDL •Non yielding support– edentulous ridges www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 5. OCCLUSAL ANALYSIS •Determine the existing occlusal scheme •Evaluate the existing occlusal contacts •Rule out for any occlusal interference •Do the occlusal equilibration www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 6. OCCLUSAL EQUIBILIRATION • The term occlusal equilibration refers to the correction of stressful occlusal contact through selective grinding. It involves the selective reshaping of tooth surface that interfere with normal jaw function www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 7. GENERAL RULES FOR GRINDING NATURAL TOOTH • Centric holding cusps should never ground unless they are in primitive contact (lingual cusp of upper and buccal cusps of lower) • Grinding should be directed such that it should direct the stresses along the long axis of the tooth • All the articulating surfaces should be rounded because all jaw movements are parabolic • Use smaller instruments for grinding www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 9. EQUILIBRATION PROCEDURE 1. interferences to the centric relation 2. interferences to the eccentric relation • Eliminating interferences to the centric relation • interferences to the arc of closure • interferences to the line of closure www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 10. Equilibration procedure • Eliminating interferences to the centric relation Interferences to the arc of closure Interferences to the line of closure www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 11. INTERFERENCES TO THE ARC OF CLOSURE As the condyle rotates each lower cusp tip and incisal edge follows an arc of closure all the way to the most closed occlusal position without any deviation •To correct it follow the grinding rule MUDL www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 12. Interferences to the line of closure Interference that causes the mandible to deviate off the line of closure Towards the cheek Towards the tongue www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 13. •Grind the buccal inclines of upper or lingual inclines of the lower BULL •Towards the cheek www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 14. •Grind the lingual inclines of the upper or buccal inclines •Towards the tongue www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 15. MOVING THE CUSP TIP BY SELECTIVE GRINDING •Tillted teeth or wide cusp tips can be adjusted to improve stability while eliminating interferences. If the mark on the upper tooth is buccal to the central fossa the lower tooth is ground to move the cusp tip lingually, if the shaping can be accomplished without shortening the cusp tip out of centric contact. www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 16. •If the mark on the upper tooth is lingual to its central fossa and stability could be improved by moving the lower cusp tip toward buccal, lower cusp is reshaped by grinding its lingual inclines to move the contact buccally. www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 17. LATERAL EXCURSION INTERFERENCES •Interferences of the balancing side •Interferences of the working side www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 18. INTERFERENCES OF THE BALANCING SIDE •Rule ---BULL • (Buccal inclines of the upper and lingual inclines of the lower) •buccal •lingual
- 19. INTERFERENCES OF THE WORKING SIDE Rule --LUBL (Lingual inclines of the upper and buccal inclines of the lower) www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 20. PROTRUSIVE INTERFERENCES •Rule - DUML •Distal•mesial www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 21. FACE BOW TRANSFER •To relate the maxillary cast to the condylar element of the articulator at the same orientation that the maxillary teeth have to the condyles •To simulate the arc of the closure •It is the distance between the head of the condyle to the mesial tip of central incisor www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 22. TYPES OF FACE BOW •Kinematic facebow •D5A •TMJ KINEMATIC FACEBOW • Arbitrary EARPIECE HANAU– 164-2-TWIRL BOW -153 WHIPMIX SLIDEMATIC •FASCIA HANAU – 132-25M 132-2C DENAR www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 23. SELECTION OF THE FACE BOW •Select according to the case •Kinematic facebow Requires additional equipments,time consuming & technique sensitive • when VDO is planned to increase, then ideally Kinematic facebow should be used •Select a facebow that is compatible with the articulator to be used www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 24. •Arbitrary face bows such as ear piece face bow & fascia face bow have their own accuracy limitations. However , a correct arbitrary face bow transfer is better than an inaccurate time consuming hinge axis record. •In the absence of true hinge axis mounting , arbitrary face bow serves the purpose,but to a lesser accuracy.”www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 25. ARBITRARY HINGE AXIS LOCATION •Selection of Arbitrary hinge axis points will depend on the type of facebow & articulator being used Standard procedures followed to locate arbitrary hinge axis www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 26. BEYRON’S POINT: 13mm Anterior to the posterior margin of tragus on a line from center of tragus to outer canthus of eye. 11-5 ARBITRARY HINGE AXIS LOCATION: scribing a horizontal line From superior notch of tragus of ear to outer canthus of Eye.Point marked 11mm anterior on the tragus from which a point 5mm down is marked at right angle to tragus canthus line to locate arbitrary hinge axis. DAWSONS PALPATION www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 27. RECORDING OF CENTRIC RELATION •Chin point guidance •Dawson's bimanual palpation •Tongue to palate •Alteration of protrusion and retrusion •Using an occlusal splint www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 28. CHIN POINT GUIDANCE www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 29. DAWSON'S BIMANUAL PALPATION www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 30. MEDIA FOR RECORDING CENTRIC RELATION •Waxes •Zinc oxide eugenol paste •Plaster of paris •Acrylic resin •Polyether Elastomers •Silicone Elastomers www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 31. INTEROCCLUSAL REGISTRATION MATERIAL Limited resistance before setting to avoid displacing the teeth or the mandible during closure. •Rigid after setting. •Minimal dimensional changes after setting. •Accurate record of the incisal and occlusal surface of the teeth. •Easy to manipulate. • The records should be verifiable. •General requirements www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 32. WAXES •Thermo-plastic waxes are frequently used. • These are widely accepted due to its ease of manipulation. www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 33. ZINC OXIDE EUGENOL PASTE •Advantages •Uniform in consistency •Adheres to the carrier •Rigidity and inelsticity after the final set. •Accuracy in recording occlusal and incisal surface. •High degree of repeatability. •Disadvantages Long setting time Brittle
- 34. PLASTER •It is difficult to handle because this is fluid and unmanageable prior to setting. •Brittle after setting www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 35. SILICONE ELASTOMERS •Advantages •Accuracy Stability after setting Does not require a carrier •Disadvantage Compression of set material www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 36. POLYETHER ELASTOMERS •Advantages •Accuracy •Stability after polymerization •Does not need a carrier. •Disadvantages •Resiliency www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 37. ESTABLISHING OCCLUSAL RELATIONSHIPS •Recording of occlusal relationship for RPD vary from simple opposition of casts to the recording of jaw relationship for complete denture •Natural teeth will influence jaw movement and dictates the placement of teeth and occlusal scheme for RPD www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 38. HORIZONTAL JAW RELATION CENTRIC RELATION & PLANNED INTERCUSPAL POSITION •If CR & planned ICP are coinciding •fabricate the restoration in centric relation •If CR & planned ICP are not coinciding and planed ICP is clearly defined then •fabricate the restoration in planned ICP www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad
- 39. •If CR & ICP are not coinciding and planed ICP is not clearly defined • fabricate the the restoration in centric relation •If posterior teeth are absent in one or both the arches •fabricate the the restoration in centric relation www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 40. METHODS FOR ESTABLISHING OCCLUSAL RELATIONSHIP 1. Direct opposition of casts 2. Interocclusal records with posterior teeth remaining 3. Jaw relation using occlusal rims on record bases 4. Jaw relation records made entirely on occlusal rims 5. Establishing occlusion by the recording of occlusal pathways
- 41. DIRECT OPPOSITION OF CASTS •Only few teeth are to be restored •Three wide spaced stable contacts •No evidence of occlusal disharmony •Perpetuates the existing occlusal vertical dimension and any occlusal disharmony www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 42. INTEROCCLUSAL RECORDS WITH POSTERIOR TEETH REMAINING •Modification of first •Indicated in cases like class III or IV •unsupported side is supported with wax •Metal reinforced wafer/baseplate/set up wax can be used •Excess wax that is contacting with the mucosal surfaces are removed •To avoid distortion metal oxide paste can be used
- 43. OCCLUSAL RIMS ON RECORD BASES •One or more distal extension areas are present Long span of edentulous area •When opposing teeth do not meet •Record bases should be made on the master casts or its duplicate cast (functional or anatomical impression) •Record bases can be of •VLC / Autopolymerising resin / Cast metal / Compression molded / Heat curedwww.asiandentalacademy.o rg Above KFC Restaurant main Road
- 44. METHODS FOR RECORDING CR ON RECORD BASES •Softened wax or Modeling plastic occlusal rims can be used •Slightely reduced in height at the established vertical dimension •A single stop is added to maintain the height •Impression plaster ZnOE paste may be used for as recording medium www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 45. JAW RELATION RECORDS MADE ENTIRELY ON OCCLUSAL RIMS when no remaining natural teeth contact exist Complete denture opposing a bilateral distal extension edentulous areas some direct Interocclusal record or Styles tracing method can be used for recording jaw relation www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 46. ESTABLISHING OCCLUSION BY RECORDING OF OCCLUSAL PATHWAY •Record bases are made on the master cast •Wax used should be hard enough to support the biting forces •Peck’s purple hard inlay wax can be used •It should be wide bulky keep wax 1-3mm high •Ask the patient to wear for 24 to 48 hours •Should be worn in night also, it is only removed during meals
- 47. •After 24 hours wax should show continious gloss •Remaining teeth should be in positive contact •Boxing of the registration is done with modeling clay after it has reseated and secured on to the the master cast •Only the registration area & vertical stops are left exposed •It is then filled with hard stone to form an occluding template www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 48. BALANCED OCCLUSION • There should be bilateral simultaneous contact of anterior and posterior teeth during centric relation as well as during protrusive and lateral excursive movements of the mandible.. • useful in complete denture construction, to prevent tipping of dentures. • For natural dentition, bilateral tooth contact during eccentric closure and/or excursive movements of mandible does not function well. • There is development of occlusal awareness, which is liable to trigger neuromuscular hyperactivity that leads to bruxism and the creation of excess lateral forces on the teeth. There is excessive frictional wear on the teeth. •
- 49. UNILATERALLY BALANCED OCCLUSION (GROUP FUNCTION) • Schuyler, Pankey, Mann, Ramford •This depicts that there is contact of all the teeth during centric positions with some freedom of movement anteroposteriorly. • This centric slide of about 0.2 to 1mm at the same vertical dimension is known as long centric. • Disclusion occurs during protrusive movement beyond the long centric. •During lateral movement disclusion occurs against the canine and buccal cusps of maxillary and mandibular premolars and molars on the working side. This is referred to as group function. www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 50. •There are no tooth contacts on the non-working side during lateral excursive movement. •The group function of the teeth on the working side distributes the occlusal load on all the teeth •The absence of contact on the non-working side prevents those teeth from being subjected to the destructive, obliquely directed forces found in non- working interference. www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 51. CANINE PROTECTED OCCLUSION •Mutually Protected Occlusion •D’Amico, Stuart, Stallard and Lucia and members of Gnathological Society. anterior teeth bear the entire load and the posterior teeth are disoccluded in any excursive position of the mandible. As soon as mandibular movement occurs, there is an immediate separation of the posterior teeth without any further contact. As the condyles follow the anatomic pathway of the slopes of their respective fossa and eminence and the anterior teeth act as the anterior stops to discluded the posterior teeth.
- 52. •During excursive mandibular gliding movements condylar guidance and anterior guidance will – act together to disclude the posterior teeth preventing collision of the posterior teeth during lateral and protrusive movement. •Lateral excursion may also be guided by the central and / or lateral incisors on the working side with the canine. Anterior teeth, particularly maxillary teeth have extremely sensitive proprioceptive systems surrounding them in the periodontium more so than for any other tooth. www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 53. •A canine can withstand the forces of occlusion during the discluding movement due to its shape, length and heavy bone investment. • Mandible is a lever of class –III type, The further anteriorly the initial tooth to tooth contact occurs (Larger lever arm) the less effective will be the forces exerted by the musculature and the smaller the load placed on the teeth www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 54. OCCLUSAL CONTACTS •Bilateral simulatanious contacts on all the teeth in centric occlusion •Opposing RPD have no anterior contacts •During protrusion no posterior contacts are desired exept in cases of opposing CD www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 55. •Maintain patients existing centric occlusal position if a physiologic state exist anterior slide of less than 2mm is acceptable •Try to achieve cuspid protected occlusion as per as possible •Reduces occlusal wear and horizontal stresses on posterior teeth or ridges •articulator selection is less critical www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 56. •Maintain patients existing centric occlusal position if a physiologic state exist anterior slide of less than 2mm is acceptable •Try to achieve cuspid protected occlusion as per as possible •Reduces occlusal wear and horizontal stresses on posterior teeth or ridges •articulator selection is less critical www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 57. IF CANINE IS PERIONDONTALLY COMPROMIZED •Establish group function or unilateral balanced articulation •Use fully adjustable articulator or •record FGP with simple articulator www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 58. CATEGORIES OF MOST FREQUENT COMBINATIONS OF DENTULOUS AND EDENTULOUS ARCHES •Unilateral or bilateral edentulous areas and a natural cuspid protected occlusion •Retain the cuspid protected occlusion Posterior teeth will disengage immediately upon lateral movement •Minimal lateral interferences • Remove all protrusive interferences simple articulator can be usedwww.asiandentalacademy.o rg Above KFC Restaurant main Road
- 59. • Articulator selection is important especially fully adjustable instrument or with the functionally generated path technique. •The second most common group is unilateral edentulous area & a group function occlusion on that side of the arch. •Develop group function on that side www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 60. BILATERAL EDENTULOUS AREAS & ALSO WHO HAD BILATERAL GROUP FUNCTION ON BOTH THE SIDE •Retain the bilateral group function occlusion on both the sides www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 61. BILATERAL EDENTULOUS AREAS & WHO HAVE UNILATERAL POSTERIOR OPPOSING TEETH IN OCCLUSION WITH GROUP FUNCTION •A unilateral group function is retained on that side of the arch where natural teeth are present •A canine protected occlusion developed on the side to be restored www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 62. BILATERAL EDENTULOUS AREAS OPPOSING COMPLETE DENTURE •Establish the balanced occlusion www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 63. ARRANGEMENT OF THE TEETH •Teeth should be selected according to the conventional principles •It is not mandatory for replacing exact amount and type of the teeth that were missing •Arrange the teeth on the crest of the ridge, can be arranged slightly lingually or buccally in case of FGT •Should not arrange the teeth on curvature of the ramus or on the maxillary tuberosity www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 64. ARRANGING THE TEETH TO AN OCCLUDING TEMPLATE •Teeth should be arranged buccolingualy in the center of the opposing template •Opposing natural teeth are present then arrange it strictly according to the template •Opposing artificial teeth are there arrange the teeth considering both the template and ridge www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 65. SUMMARY •Weinberg has stated “In the final analysis the true value of our individual work can be measured only by the degree of firmness with which we practice the art of dentistry, rather than the particular school of thought to which we adhere”. www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 66. DIFFERENT COMBINATIONS AT A GLANCE Posterior restoration being fabricated Occlusal scheme Occlusal morphology Balanced Fixed or Tooth – Supported removable Patient presents with •Natural cuspid protected • Natural group function •Cuspid missing or periodontally compromised Opposing complete denture Cuspid protected Group function Group function balanced Match opposing Match opposing Match opposing Match remaining No Unilateral Unilateral Bilateral
- 67. Posterior restoration being fabricated Occlusal scheme Occlusal morphology Balanced Removable unilateral distal extension patients present with •Natural cuspid protected • Natural group function •Cuspid missing or periodontally compromised Opposing complete denture Cuspid protected Group function Group function balanced Match opposing Match opposing Match opposing Match remaining No Unilateral Unilateral Bilateral www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 68. Posterior restoration being fabricated Occlusal scheme Occlusal morphology Balanced Removable bilateral distal extension patients present with •Natural cuspid protected ·unilateral Natural group function bilateral Natural group function •Cuspid missing or periodontally compromised Opposing complete denture Cuspid protected Group function Group function Group function balanced Match opposing Match opposing Match opposing Match remaining Match remaining No Unilateral Unilateral Bilateral Bilateral or unilateral www.asiandentalacademy.o rg Above KFC Restaurant main Road
- 69. www.asiandentalacademy.org Above KFC Restaurant main Road Kothapet Hyderabad Courses offered: Rotary Endodontics Smile Designing Fellowships Implantology Digital Smile Designing