full mouth rehabilitation part 1

FMR

1. FULL MOUTH REHABILITATION Presented by Dr.Namitha AP 3rd MDS 1

2. CONTENTS INTRODUCTION DEFFINITIONS OBJECTIVES OF FMR INDICATIONS OF FMR REASONS FOR FMR LIMITATIONS OF FMR MASTICATORY SYSTEM DISORDER DIAGNOSTIC WAX UP EXAMINATION, DIAGNOSIS AND TREATMENT PLANNING IN FMR VERTICAL DIMENSION CENTRIC RELATION LONG CENTRIC OCCLUSAL EQUILIBERATION/PRINCIPLES OF OCCLUSAL CORRECETION TREATMENT PROCEDURES AND TECHNIQUES IN FMR FINAL RESTORATIONS FOR FMR COMMON PROBLEMS AND DIFFICULTIES IN FMR POST OP CARE TECH FUTURE IN FMR CONCLUSION REFERENCES 2

3. Ultimate goal - Optimum oral health Introduction The term ‘full mouth rehabilitation’ is used to indicate extensive and intensive restorative procedures in which the occlusal plane is modified in many aspects in order to accomplish “equilibration”. Multidisciplinary Approach Both function and health can be restored in badly detiorated , diseased mouths by utilizing modern techniques of oral rehabilitation 3

4. Definition (GPT9) Full mouth rehabilitation is defined as the restoration of the form and function of the masticatory apparatus to as nearly a normal condition as possible The word rehabilitate implies ‘ To restore to good condition or to restore to former privilege’. Reynolds JM. Modern gnathological concepts—Updated: By Victor O. Lucia, DDS, FACD Chicago, 1983, Quintessence Publishing Co., Inc. 439 pages, illustrated, indexed . All the procedures necessary to produce healthy, esthetic , well functioning, and self-maintaining masticatory mechanism. 4

5. Objectives of FMR A static centric occlusion in harmony with centric relation. Even distribution of stresses in centric occlusion and on eccentric functional inclines. Equalization of forces directed against supporting structures Restoration of normal healthy function of the masticating apparatus Irving Goldman: The goal of full mouth rehabilitation, J PROSTHET DENT 1951, vol 2, 246-251 5

6. Reasons for full mouth rehabilitation   O btain and maintain the health of periodontal tissues .   Temperomandibular joint disturbance   Need for extensive dentistry as in case of missing teeth, worn down teeth and old fillings that need replacement .   Esthetics as in case of multiple anterior worn down teeth and missing teeth. Reynolds JM. Modern gnathological concepts—Updated: By Victor O. Lucia, DDS, FACD Chicago, 1983, Quintessence Publishing Co., Inc. 439 pages, illustrated, indexed . 6

7. INDICATIONS   Restore impaired occlusal function Preserve longevity of remaining teeth Maintain healthy periodontium Improve objectionable esthetics pain and discomfort of teeth and surrounding structures CONTRAINDICATIONS Malfunctioning mouths that do not need extensive dentistry and have no joint symptoms should be best left alone. Prescribing a full mouth rehabilitation should not be taken as a preventive measure unless there is a definite evidence of tissue breakdown. No pathology- No treatment. Reynolds JM. Modern gnathological concepts—Updated: By Victor O. Lucia, DDS, FACD Chicago, 1983, Quintessence Publishing Co., Inc. 439 pages, illustrated, indexed . 7

8. Classification of patients requiring occlusal rehabilitation   Classification by Turner and Missirlain (1984) The patients were classified into three categories – Category 1 - Excessive wear with loss of vertical dimension. Category 2 - Excessive wear without loss of vertical dimension of occlusion but with space available. Category 3 - Excessive wear without loss of vertical dimension of occlusion but with limited space available Turner KA, Missirlian DM. Restoration of the extremely worn dentition. Journal of Prosthetic Dentistry. 1984 Oct 1;52(4):467-74. 8

9. Restoring vertical dimension at occlusion loss of occlusal vertical dimension due to unstable posterior occlusion or congenital disease and exhibit excessive wear of anterior teeth. method to confirm loss of vertical dimension is with trial restorations A removable occlusal overlay splint or a treatment partial denture that restores the occlusal vertical dimension is given for 6-8 weeks and the patient is evaluated for comfort and function. teeth are prepared and provisional fixed restoration are given 2-3 months . Then the final restorations can be given Category 1 J PROSTHET DENT 1984, vol 52, 467-474 9

10. A long history of gradual tooth wear caused by bruxism or moderate oral habits Anterior slide is present from centric relation to centric occlusion. Equilibration or stability of posterior teeth for stability in centric relation, in combination with enameloplasty of opposing teeth can provide sufficient space for restorative materials. gingivoplasty and gingivectomy , 2-3mm of supporting bone can usually be removed without jeopardizing periodontal support, dynamic recordings of mandibular movement ,are recommended for this type of rehabilitation . Category 2 10

11.   exhibit minimum posterior wear but excessive gradual wear of anterior teeth over many years. Centric relation and centric occlusion are coincidental. Restoring this patient is most difficult because vertical space must be obtained for restorative materials Increasing the occlusal vertical dimension to achieve space for restorative materials where there has apparently been no loss of occlusal vertical dimension is seldom advisable; but if deemed necessary , the increase should be minimal and for restorative needs only. Trial restorations are crucial and must be evaluated for longer period of time to ensure patient accommodation to the altered occlusal vertical dimension Category 3 11

12. Classification by Brecker Group I Class I – Patients with collapse of vertical dimension of occlusion because of shifting of existing teeth caused by failure to replace missing teeth.   Class II – Patients with collapse of vertical dimension of occlusion because of loss of all posterior teeth in one or both jaws with remaining teeth in unsatisfactory occlusal relationship.    Class III – Patients with collapse of vertical dimension of occlusion because of excessive attritional wear of occlusal surfaces. Brecker SC. Clinical procedures in occlusal rehabilitation. WB Saunders; 1966. 12

13. Group II   Class I – Patients with all or sufficient natural teeth present, with satisfactory occlusal relationship . Class II – Patients with limited teeth present but in satisfactory occlusal relationship r equiring aid in the form of occlusal rims. Group III – Patients requiring maxillofacial surgery or orthodontic treatment as an aid in restoring the lost vertical dimension. Group IV – Patients in whom sectional treatment is required over extended periods of time because of status of health of the patient, age or economic factor .   Clinical procedures in occlusal rehabilitation .W.B Saunders,Philidelphia 1958 13

14. Etiology of extremely worn dentition Congenital abnormalities Amelogenesis imperfecta Dentinogenesis imperfecta Parafunctional occlusal habit Chronic bruxism and other habits Abrasion Erosion Loss of posterior support Bernard smith :Tooth wear : Etiology and diagnosis Gerodontology Text Book 1994, 88-102 46/400 14

15. Advanced occlusal disease Anterior guidance attrition Sensitive teeth Sore teeth H ypermobility Spilt teeth and fractured cusps Painful musculature Examples of occlusal disease Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31.page no. 21-26 15

16. D iagnosis Ist appointment Listen to p atient’s opinion and expectations Make diagnostic casts Radiographs Bite records and facebow transfer IInd appointment Individual tooth is meticulously examined Extracted or restored Serve as abutments for RPDs or fixed prosthesis Tentative treatment plan done EXAMINATION DIAGNOSIS AND TREATMENT PLANNING IN FMR Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31.page no. 360-363 16

17. Diagnostic aids Medical history Dental history Behaviour evaluation Radiographs – Complete mouth periapical radiographs and orthopentamograph Photographs – to remind previous state of mouth prior to restorative therapy Clinical examination Diagnostic wax-up Computer imaging CBCT Bowley JF, Stockstill JW, Attanasio R. A preliminary diagnostic and treatment protocol. Dental Clinics of North America. 1992 Jul;36(3):551-68. 17

18. DIAGNOSTIC WAX UP The process of converting the programmed treatment plan into a three dimensional visualisation Before diagnostic wax-up, the occlusal discrepancies in centric and eccentric occlusion should be eliminated Thus planning of subgingival margins or surgical crown lengthening required can be done Then wax is used to appropriately shape all crowns and final prosthesis is planned c an be used to prepare an elastomeric putty mould and used for temporization or sectioned through long axis of tooth to act as reduction guide intra-orally. Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31.page no. 365-366 18

19. Steps in the diagnostic wax up Step 1: Mount upper and lower casts with centric relation bite record and facebow. Duplicate the casts to preserve the original conditions. Step 2: Verify the accuracy of the mounting. Step 3: Examine the occlusal relationship on the casts. Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31.page no. 365-366 19

20. Step 4: Lock the centric latch when observing the casts. Step 5: Determine the correct vertical dimension. Step 6: Return the condyles to centric relation and lock the centric lock. Occlusal interferences should be eliminated by selective grinding on the casts until the incisal pin contacts the guide plate. At that point, the original vertical dimension will have been re-established in centric relation. If a change in VDO is needed to fulfil requirements for stability, it can be determined now. Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31.page no. 368 20 Unlock the centric latch and close the teeth into maximum intercuspation . This is the vertical dimension established by the elevator muscles. Lower the incisal guide pin so it touches the guide table.

21. Step 7: Observe the teeth that were reshaped. Step 8: Remove unsavable teeth from the casts. From the clinical exam, all teeth that cannot be saved are marked with an X. Step 9: Mark decisions that have been made to use certain types of restorations. For example, in the figure the two upper molars have been predetermined to need crowns (C). Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31.page no. 368,369 21

22. Step 10 : Equilibration is the first treatment option to explore. The jaw-to-jaw relationship at the first point of tooth contact in centric relation. Equilibration of the casts clearly shows that reshaping the teeth is a good choice of treatment because contact with the canines is achievable by selective grinding away of the deflective interferences . Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31.page no. 369 22

23. Step 11: Examine the plane of occlusion. If the casts were mounted with a facebow that was parallel with the eyes, the incisal plane and the occlusal plane will relate to the bench top. If the occlusal plane is slanted in the mouth (yellow line), it will be slanted on the articulator (red line) Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31.page no. 370 23

24. The occlusal plane established by the simplified occlusal plane analyzer. Model is trimmed back to the established new occlusal plane. Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31.page no. 370,371 24

25. Note how the buccal surfaces have been contoured to move the cusp tip more in line with the upper teeth. The wax-up has been started. The completed wax-up. These corrected casts are now used to form a putty matrix for fabrication of provisional restorations. They are also the perfect visual aid when presenting the treatment plan to the patient . Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31.page no. 371 25

26. Step 12: Establish stable holding contacts on the anterior teeth. Step 13: Correct lower incisal edges if needed. This refers to both position and contour. Unmounted casts do not provide the information needed to fulfill this objective Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31.page no. 371,372 26

27. Step 14: Start with the lower anterior teeth. Step 15: Re-evaluate the total occlusion with the upper cast to see it can be adapted to occlude with the lower arch. simplifies the whole wax-up. Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31.page no. 371,372 27

28. Step 16: Establish holding contacts on the upper anterior teeth This diagnostic wax-up positioned the incisal edges forward and also made the teeth longer. Casts of a patient with a tight neutral zone that positioned the upper anterior teeth with a lingual inclination . Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31.page no. 374 28

29. A digital photograph of this patient shows the incisal edges in line with the inner vermillion border of the lower lip. It also shows a lingual inclination of the upper anterior teeth. This photograph shows how the provisional restorations made from the wax-up had to be recontoured back to achieve a comfortable lip closure path and phonetics. Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31.page no. 375 29

30. Cast of poorly contoured anterior restorations. Note the contour of the pontics where they meet the ridge. Cast showing defect of lost labial plate of bone that makes it impossible to establish gingival contours on pontics that are esthetically pleasing. Fill-in of area with pink wax will be used to communicate desired result to the surgeon. A bone augmentation was needed to achieve the planned contour. All guesswork was eliminated. Recontouring of the anterior teeth on the cast will be used to form provisional restorations, as well as explain the treatment goal to the patient and the surgeon. Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31.page no. 376,377 30

31. Treatment plan Comprehensive treatment plan must be established prior to start of the treatment . Communication and patient education are essential in order to match the dentist’s and patient’s definition of success 31 Immediate treatment Definitive treatment

32. Preprosthetic phase To develop proficiency in diagnosing the need of occlusal rehabilitation, periodontist , orthodontist , endodontist , oral surgeon and prosthodontist must all be integrated in establishing an environment conducive to oral health. Minor orthodontic tooth movement-tooth can be uprighted, rotated, moved laterally, intruded or extruded to improve axial alignment, create favorable pontic space and direct occlusal forces along the long axis of teeth. Scaling and root surface curettage bring back the gingival health. Surgical crown lengthening - to improve esthetics and provide adequate retention when clinical crown is short. Free autogeneous gingival graft - increase width of inadequate attached gingiva caries, decalcification, erosion, attrition, abrasion, exposed root surface or fractures - restore where required. Elective endodontic treatment may be necessary for supraerupted or malaligned teeth post and core Infected root pieces, hopelessly mobile teeth and impacted or unerupted supernumerary teeth are removed. Block resection and movement of both maxillary and mandibular segments Elective soft tissue surgery ,alteration of muscle attachments and alveoplasty 32

33. Postponing treatment until adulthood IMPORTANCE OF IMMEDIATE TREATMENT 33

34. Vertical Dimension : The distance between two selected anatomic or marked points, one on a fixed and the other on a movable member. Vertical Dimension of Rest : The postural position of the mandible when an individual is resting comfortably in an upright position and the associated muscles are in a state of minimal contractual activity. Vertical Dimension of Occlusion : The distance between two selected anatomic or marked points when in maximal intercuspal position.

35. Dawson P E. Evaluation, diagnosis and treatment of occlusal problems. pp 280-285. St Louis, MO: CV Mosby, 1989. UNDERSTANDING VERTICAL DIMENSION You cannot determine vertical dimension based on whether the patient is comfortable. Measuring the freeway space is not an accurate way to determine the correct vertical dimension of occlusion. Determining the rest position of the mandible is not a key to determining vertical dimension. Lost vertical dimension is not a cause of temporomandibular disorders.

36. The mandible-to-maxilla relationship, established by the repetitive contracted length of the elevator muscles, determines the VDO. Dawson P E. Evaluation, diagnosis and treatment of occlusal problems. pp 280-285. St Louis, MO: CV Mosby, 1989 page number 115 The teeth continue to erupt until they meet an opposite force of equal intensity to the eruptive force. The jaw-to-jaw dimension is maintained with such consistent muscle contraction length that even rapid abrasive wear does not cause a loss of vertical dimension (A). The alveolar process lengthens in an amount equal to the wear.

37. METHODS OF DETERMINING VERTICAL RELATION Abduo J, Lyons K. Clinical considerations for increasing occlusal vertical dimension: a review. Australian dental journal. 2012 Mar;57(1):2-10.

38. Calliper Method Willis gauge Boley gauge Geerts GA, Stuhlinger ME, Nel DG. A comparison of the accuracy of two methods used by pre-doctoral students to measure vertical dimension. The Journal of prosthetic dentistry. 2004 Jan 1;91(1):59-66.

39. Can vertical dimension be altered? 39

40. 40

41. When Must The Vertical Dimension Be Changed? Extremely worn dentition Crown lengthening vs. increasing the VD Restoring severe arch mal-relationships Extreme occlusal plane problems Anterior open bite Why Not Increase The VD? Any disharmony in the system provokes adaptive responses designed to return the system to equilibrium. Adaptive process is not always predictable. No benefit over time to the patient whatsoever. The goal of occlusal therapy is to minimise the requirements for adaptation. Segmental - instability of the entire occlusal harmony. 41

42. Methods of obtaining space for restoring worn teeth Selective grinding Badly worn anterior teeth that have drifted into anterior wear end to end relationship Posterior teeth that interfere, deflect the mandible forward and cause excessive wear on upper anterior lingual incline. Interferences should be eliminated by selective grinding so that mandible can close at centric relation 42 Bloom DR, Padayachy JN. Increasing occlusal vertical dimension—Why, when and how. British dental journal. 2006 Mar;200(5):251-6.

43. Periodontal surgery I ncludes gingivoplasty , osteoectomy to gain clinical crown length is sometimes required for retention and esthetics. 2-3mm of supporting bone can usually be removed without jeopardizing periodontal support. 43

44. There are occasionally situations where restoration of a worn dentition can be accomplished only by increasing occlusal vertical dimension, even though a loss of vertical dimension is not diagnosed Splints and provisional restorations If deemed absolutely necessary, modification of vertical dimension should be accomplished through cautious trials with removable occlusal splints 44

45. Dahl appliance P artial coverage splint, 2-4 mm thick, designed to depress the opposing teeth against which it contacts and to allow the unopposed teeth to overerupt . It contacts anterior teeth and allows posterior teeth to erupt. Alveolar remodeling ensures that anterior teeth are not intruded into the bone, with a resulting loss of crown height Poyser , N., Porter, R., Briggs, P.  et al.  The Dahl Concept: past, present and future.  Br Dent J   198,  669–676 (2005 ). https ://doi.org/10.1038/sj.bdj.4812371 45

46. Dahl described the use of cobalt chromium appliance but its modifications of acrylic and bonded composite have been used satisfactorily. Most space is created between 2-4 months of continuous wear Irish Dentist July 2011 46

47. Centric Relation It is defined as the maxillo -mandibular relationship in which the condyles articulate with the thinnest avascular portion of their respective discs with the complex in the anterior-superior position against the slopes of articular eminences. This position is independent of tooth contact 47 Centric relation is the only condylar position that permits an interference-free occlusion

48. Methods available to guide the mandible into centric relation 1.Chinpoint Guidance method or one handed technique- Guichet It places the condyles in most posterior and superior position which can result in trauma to TMJ. not advocated . 2. Unguided method Brill introduced a muscular position which allows patient’s natural muscle functions to position the mandible into centric relation position. 3 . Bilateral manipulation method Dawson introduced this method in which the condyles are in their most superior position in the gleoid fossa. Firmness of upwardly directed pressure at or near the angle of the mandible to ensure that the condyles are seated seated againt the eminence Brit Dent J.1959, vol 106, pg 391-400 48

49. 49 T aking centric bite records Factors considered while making interocclusal records Purpose:to capture ,in some stable material ,the relationship of the mandible to the maxilla when the condyles are in their terminal axis position 4 B asic techniques

50. Wax bite procedure M ost popular procedure (simple) Extra hard baseplate wax is an excellent bite material When it is warm it becomes soft enough not to cause movement of teeth . I t should be brittle and not bend to mould itself to fit the models as it will mask the errors if not rigid. This method is not suitable for patients having extremely mobile teeth or large edentulous area. Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.93 50

51. Anterior stop technique Extremely accurate Allows the condyles to seat up without any possible deviation from posterior teeth. When mandible is closed the lower incisors strike against a stop that is precisely adapted to fit against the upper incisors thin enough so that the first point of posterior contact just barely misses Anterior stop may be made from acrylic or hard compound 51

52. Mandibular deprogramming Ask the patient to bite on these with anterior teeth for 5 -10 minutes. The memory position of teeth intercuspation is lost 1) Cotton role 2) Anterior Jig 3) Leaf Guage 52

53. Anterior bite stops/ Jig Anterior jig prevents posterior teeth from occluding and thus disrupts the proprioceotive memory. As the anterior stop is rigid on contact with lower incisor teeth, anterior resistance is created and a mandibular leverage is created with naturally braced tripod effect along with two condyles. Jig breaks the patient’s habitual closure pattern and acts as the third leg of the tripod by creating resistance while stopping the closure. Principle Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.81 53

54. Fabrication of anterior jig C ompound is softened and added to upper incisors so that their lingual surfaces are completely covered The patient closes into the compound until the posterior teeth barely miss the contact while in supine position the lower central incisors contact the smooth lingual incline of the jig at only one point . The jig incline must stop the mandible before posterior tooth contact and should be angled 45-60 degrees posteriorly and superiorly from the occlusal plane. The jig can also be made of autopolymerizing acrylic resin on mounted casts and then adjusted intraorally . After the jig is made posterior bite record is taken Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.81 54

55. 55 Leaf Gauge – Dr James.H.Long (1973) uniform 0.1mm thickness which are sequentially numbered Most useful and practical alternative to anterior jig Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.82

56. Power Bite Proper use requires precise location of centric relation before closing power from the elevator muscles is applied. starts with a bite record made between the upper and lower anterior teeth. a softened compound that hardens after the indentations have been made between the upper and lower anterior teeth . Closure of the jaw must stop short of any posterior tooth contact . patient is then instructed to clench tightly to seat the condyles up into centric relation. The problem is that if the anterior segment of the bite is made with the mandible displaced from centric relation, the hardened material locks the jaw into that relationship and prevents the condyles from moving back and up 56

57. Use of preadapted bases I ndicated whenever there is a danger that teeth will move or soft tissues be compressed by the bite record Heated strip of dead soft wax should be added over it in edentulous region to indent the lower teeth in centric occlusion without tooth to tooth contact It is made with triple layer of extra hard baseplate wax adapted on an accurate model, usually of the upper arch to avoid dislodgement by the tongue 57

58. Manipulated centric relation closure can bring the lower anterior teeth into contact with the wax. While holding the TMJs firmly on their centric relation axis, ask the patient to lightly bite into the wax to form shallow indentations. Then chill the wax to harden it and add the putty silicone to the preformed wax base. Manipulate a verified centric relation and close into the indentations . The soft putty silicone will adapt to the opposing ridge 58

59. Central bearing point technique It enables free movement of the mandible without influence of teeth proprioceptives . Drawback is that vertical dimension must be increased considerably to accommodate the clutches and bearing point apparatus. If the terminal axis is not recorded precisely it will result in mounting error. If a central bearing point apparatus is adapted to well-fitted upper and lower clutches, all occlusal contact can be disengaged. The bite record is made between the clutches rather than directly between opposing teeth. 59

60. Long centric / Freedom in centri c D efined as ‘ freedom to close the mandible either into centric relation or slightly anterior to it without varying the vertical dimension of occlusion. When interference in centric relation is eliminated by equilibration ‘long centric will usually be provided automatically . The most important aspect is that the vertical dimension of occlusion must be the same from back to front of each long centric contact area. Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.190 60

61. Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.192,193,195 Contact in centric relation Clearance for long centric 61

62. P rocedure To determine the patient’s long centric two different colours of marking ribbon are used green or blue or black - centric relation points Red ribbon - closure from postural rest position knife edge inverted cone carborundum stone is used for accurate grinding There are no contraindications for providing the freedom. Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.196 62

63. 63 Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.196,197

64. Symptoms indicating requirement of long centric Patient says they are comfortable when lying down but interfere while sitting up Patient says teeth fit fine when dentist pushes the jaw back but hit only on front teeth if close it themselves Advantage of long centric Freedom of movement in centric occlusion provides patient comfort and reduces the tendency to bruxism and other traumatogenic influence on the supporting structures. Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.191 64

65. CUSTOMIZING THE ANTERIOR GUIDANCE Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.196,197 65

66. 66 The centric relation contacts The most critical tooth contour in the entire occlusal scheme is also the most universally mismanaged. Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.164

67. Upper half of labial surface second most important determination is upper incisal edge position . will not be precise until the upper half of the labial contour has been determined. There is no bulge in nature from the alveolus to upper labial surface ie the upper half of the labial surface is continuous with the labial surface of the alveolar process Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.164 67

68. Lower half of labial surface two planes - for incisal position and to allow the lip closure path to slide along the labial surface hence the need to roll in the incisal tip. very important step in determining horizontal position of the incisal edges lower lip can easily slide by the incisal third to seal contact with the upper lip - lip-closure path. Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.165 68

69. Incisal edge This should rest along the inner vermillion border of the lower lip and is best determined by observing the patient to counting from 50 to 55 ie 'F' sound. This needs to be in harmony with the neutral zone, lip closure path, phonetics, envelope of function and aesthetics . Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.167 69

70. Anterior guidance Contour of the lingual surface from the centric stop to the gingival margin: There should be no interferences with the 'T', 'D' or 'S' sounds. This is determined by the protrusive path but should include a 'long centric' that allows a little freedom before this path is engaged and so the lower incisors are not bound in Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.167 70

71. Restoring lower anterior teeth Lower incisal edges are the starting point for anterior guidance and “the view” when speaking. The arrangement of the entire occlusal scheme starts with the lower anterior teeth 5 important goals 1. E sthetics 2. Phonetics 3. O cclusal plane 4. Anterior guidance 5. Stability 71 Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.179

72. 72 The height of the incisal plane In ideal instances, the lower incisal edges form a continuous gentle curve that is an extension of the posterior occlusal plane Lips sealed The lower incisal edge is at the height of the juncture of the upper and lower lips when the teeth are together. On a lateral cephalometric radiograph, this usually positions the incisal edge slightly above the functional occlusal plane. Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.183,184

73. 73 Speaking Smiling Lips slightly parted “The view” when speaking is of the incisal edges of the lower anterior teeth. A varying amount of labial contour may also be on display. The upper teeth are usually hidden during speech. Only the upper anterior teeth are typically on display during smiling. The lower incisors are usually hidden during a big smile. When the jaw is at rest and the lips are slightly parted in a half smile, both upper and lower labial surfaces are about equally on display.

74. 74 Lower incisal edge contours The most important contour on the lower incisal edges is the labio-incisal line angle. The “leading edge” is important for natural appearance but also to achieve a stable holding contact against the upper lingual stop. Use of the Esthetic Checklist reminds the technician to do this on every lower anterior restoration

75. 75 The entire occlusion can be compromised by instability if lower incisal edges are not correct. It is a critical point for analysis and treatment of anterior teeth

76. Determining plane of occlusion 2 basic requirement Permit anterior guidance to disocclude posterior teeth when mandible is protruded Permit disclusion of all the teeth on balancing side when mandible is moved laterally Curvature of anterior teeth determined by- Establishing correct smile line proper phonetics Anterior guidance 76

77. CURVATURE OF POSTERIOR TEETH Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.401 77

78. Establishing plane of occlusion 3 practical methods Analysis on natural teeth through selective grinding Analysis of models with fully adjustable instrumentation Use of Pankey - Mann –Schuyler methods of occlusal plane analysis. 78

79. SOPA-simplified occlusal plane analyzer Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.401 79

80. Broadrick occlusal plane analuser The Broadrick flag accomplishes the same occlusal analysis on almost all types of semiadjustable articulators. (1) Card Index 142-101, (1) Bow Compass 142-1001 with graphite leads, an extra center point and a needle point, (1) Scribing Knife 142-3201 and (12) Plastic Record Cards 142- 3401 Card index 142-101 Bow compass 142-1001 with graphite leads 80

81. . M axillary cast mounted by Facebow transfer mandibular cast mounted in centric relation The accessory Hanau-Mount Split-Cast Mounting Plate- This split cast allows rapid cast removal and accurate replacement during the survey. visual guide for adjustment of the Articulator to protrusive or lateral interocclusal relation records Place the Card Index onto the Upper Member with the open end around the incisal pin and the slot on the side around the mounting plate thumbscrew. Orbitale Indicator be mounted to the articulator, it must me removed in order to mount the Card Index Tighten the thumbscrew to hold the Card Index in place Press a Plastic Record Card over the dowels on the right side of the Card Index. The Cards are matte finished on both sides and readily accept pencil or ink markings. 81

82. An average of a 4 " radius may be used in the majority of surveyed cases. Variation is necessary only when pronounced Curve of Spee - 3-3/4" radius flat Curve of Spee may require - 5" radius. The relatively small divergence between arcs of 3-3/4", 4" and 5" radii over the functional occlusal surfaces on the lower posterior teeth 82

83. T his point must be selected as the most desirable to “Beam” the line and plane of occlusion posteriorly. Once selected, it is marked on the cuspid and NOT CHANGED Position the center point of the Bow Compass on the anterior survey point (A.S.P.) which is usually the disto-incisal of the cuspid , If the cuspid is worn flat, the A.S.P. may be at the incisal edge With the center point of the Compass positioned on the A.S.P ., apply a long arc (about 3”) on the Plastic Record Card . The occlusal plane survey center (O.P.S.C.) will ultimately be located on some point on this arc 83

84. . Select the posterior survey point (P.S.P.) at the distobuccal cusp of the last lower molar No molars in the mandibular arch Remove the upper cast and select a P.S.P. on the modelling compound in the same manner as the P.S.P. was selected on the last molar Position the center point of the Bow Compass on the P.S.P. and apply an arc to intersect the arc from the A.S.P. as illustrated. 84

85. Alternate to the molar P.S.P. is a position on the Condylar Element of the Articulator , at its anterior intersection with the Condylar Shaft Position the center point of the Compass on this condylar posterior survey point (C.P.S.P.) and apply an arc to intersect the arc formed from the A.S.P Continue with by substituting the needle point for the graphite lead. 85

86. Place the center point of the Bow Compass, still adjusted to the 4” radius, at the intersection of arcs on the Plastic Record Card (initial occlusal plane survey center). Sweep the the needle point over the occlusal surfaces of the lower posterior teeth to see how the arc conforms to the existing occlusal plane. Shift this occlusal plane survey center (O.P.S.C.) on the long arc on Plastic Record Card, the A.S.P. line, until the most acceptable line and plane of occlusion is found. 86

87. By trial and retrial, in ideal survey center forming the most acceptable line and plane of occlusion will be located The center point of the Bow Compass is now pierced into this ideal O.P.S.C. on the Plastic Record Card and circled with pencil or ink for subsequent relocation. It may be advantageous to mark “R” (right) in the upper corner of the Plastic Record Card for identification A Plastic Record Card is then place over the dowels on the left side of the Card Index and marked “L”. Repeat the survey procedure 87

88. Measurement of difference between survey lines of different radii of curvature Various survey lines obtained from different radii of curvature 88

89. Posterior occlusion Posterior teeth should have equal intensity contacts that do not interfere with either the temporomandibular joints (TMJs) in the back or the anterior guidance in the front . The requirements for perfected posterior occlusions start with the lower posterior teeth. Three key determinants Plane of occlusion Location of each lower buccal cusp tip Position and contour of each lower fossa 89

90. Placement of Lower Buccal Cusps determined on the basis of providing the optimum effect for buccolingual stability, mesiodistal stability, and noninterfering excursions. Upper central groove position is analyzed . On each upper occlusal surface, a line is drawn from mesial to distal in the central groove. The ideal contact point for each lower buccal cusp tip is usually located somewhere on this line . In some tilted teeth, it is advantageous to move the central groove to gain better direction of forces through the long axis. If moving the central groove will enable the stresses to be directed more nearly through the long axis of any upper tooth, the improved central groove position should be so noted on the upper cast by drawing a new line. 90 Buccal cusp placement for buccolingual stability

91. 91 A mark is made on each lower tooth to indicate the position of the buccal cusp that would be optimum for buccolingual stability and direction of force Alignment of the optimum lower buccal cusp position against optimum upper central groove position is evaluated.

92. Mesiodistal placement of lower buccal cusps The best mesiodistal stability is attained by placement of the lower buccal cusps in upper fossae. Placement in the fossae directs the stresses properly through the long axis, eliminates any possibility of plunger cusp food impaction at contact, and is stable. There is no tendency for cusp tips to migrate out of properly contoured fossae 92

93. Locating the lower buccal cusps for noninterfering excursions Determining which fossa the lower buccal cusp should contact depends on where the cusp travels when it leaves centric relation . The mesiodistal placement of each lower buccal cusp is determined when one locates it in the fossa that permits excursions from centric relation without interference Contouring cusp tips 93

94. 94 Placement of lower lingual cusps In normal tooth-to-tooth relationships, the tip of the lower lingual cusp never comes in contact with the upper tooth . Even though the buccal incline of the lower lingual cusp can be made to contact in working excursions act as a gripper and a grinder by passing close enough to the upper lingual cusps to aid in tearing, crushing, and shearing the food that is caught between the opposing surfaces. The position of the tip should have enough lingual overjet to hold the tongue out of the way, but it should always be located over the root, within the long axis . The measurement between buccal cusp tip and lingual cusp tip should not be much greater than half of the total buccolingual width of the tooth at its widest part . lower lingual cusp height should be about a millimeter shorter than the buccal cusp. Cusp height can be lowered further in the first premolar

95. 95 Countouring the lower fossae As the mandible moves right or left from centric relation, its front end should be guided down the lingual incline of the upper canine. When it serves as the lateral anterior guidance, the lingual incline of each upper canine dictates the fossa contour of each lower incline that faces it

96. If Only Lower Posterior Teeth Are to Be Restored Cusp tip position and fossa contours for lower posterior restorations are aligned and contoured in relation to the existing upper teeth on the opposing cast . Lower fossa contours will be established to conform to the upper lingual cusps. Fossa walls can be carved to be discluded by the anterior guidance without complication. If Both Upper and Lower Posterior Teeth Are to Be Restored If posterior disclusion is the goal, it is easily achieved by making fossa walls flatter than the lateral anterior guidance, and establishing an acceptable occlusal plane that permits the anterior guidance to disclude the posterior teeth in all excursions. After the anterior guidance has been finalized, the simplest method for ensuring that fossa walls will be discluded in lateral excursions is through the use of a fabricated fossa contour guide. 96

97. Determining and Carving Lower Fossa Contours Purpose to ensure a noninterfering accommodation for the upper lingual cusps. It will provide a fossa contour that is compatible with the lateral anterior guidance regardless of the contour of the anterior guidance. It can be easily modified to provide extra freedom. Fossa contour guide can be used in any stage of wax-up or even porcelain application . used only if both upper and lower posterior teeth are to be restored The anterior guidance must be correct before the guide is fabricated or before occlusal contours can be determined for lower posterior restorations 97

98. 98 Making the fossa contour guide The anterior guidance may be corrected in provisional restorations, and a centrically mounted cast of the provisional restorations in place may be used to determine the allowable fossa-wall angulation for the posterior restorations. The guide is usually made when the casts are mounted, but it is not used until the posterior wax-up is done or the porcelain is being applied and contoured. Step 1 The regular incisal guide pin is removed and replaced with the special fossa-contour pin. The blade of the pin is indented into a mound of wax on a flat plastic guide table

99. 99 The upper bow is moved into left and right excursions, allowing the contours of the lateral anterior guidance to determine the path that the guide pin cuts into the wax. When the lateral guidance paths have been cut sharply into the wax, the special pin is raised. It is then used to hold a handle for the fossa guide. Make the handle by cutting off the tip of a plastic protector for a disposable needle. The large end fits snugly onto the raised special pin.

100. 100 Resin is wiped into the hollow end of the handle, and the pin is lowered so that the two portions flow together. The resin is allowed to set hard. The guide can then be removed. The wax on the guide table is then no longer needed, and so it can be cleaned off after the guide is removed. A creamy mix of self-curing acrylic resin is flowed into the indentation in the wax. Because of the design of the special wax-cutter pin, the lateral anterior guidance angle will be evident as a sharp line running along the bottom edge of the acrylic guide. The edge is marked with a pencil, and any excess acrylic resin may be ground off in front of the line.

101. 101 One may actually hollow-grind the front surface down to the line to make a scoop-shaped guide, which is excellent for shaving out wax from the fossae. To ensure posterior disclusion , the fossa walls must be flatter than the lateral anterior guidance, so the fossa guide angle is flattened on the sides and the tip is rounded to a more opened-out fossa. The fossa guide can be used to contour the wax patterns or as a guide for shaping occlusal surfaces in porcelain. The tip of the guide should be able to touch the base of the fossa without interference from the walls of the fossa.

102. Carving the marginal ridges The ridges should be contoured to reflect food away from the contact, which means directing it into the fossae. Sluiceways should provide an escape route for the bolus out of the fossae toward the lingual as the stamp cusps crush the food against the fossae walls. Countouring ridges and grooves work out the fossae contours first and then functionalize and beautify the anatomy by placing the appropriate grooves at the working, protrusive, and balancing excursion . There can be no entanglement of cusps in grooves that have been made into inclines that are already out of reach. Other grooves may be added as desired to improve esthetics or to provide more ridges for better masticatory function 102

103. 103 Upper posterior teeth last segment to be restored . It is the fixed posterior segment, and its cusps, inclines, grooves , and ridges are placed and contoured to accommodate the many border movements of the lower posterior teeth . If the upper contours are determined by the paths of the lower posterior teeth, both the form and the paths of the lower teeth should be finalized before the upper teeth are restored

104. LENGTH OF GROUP FUNCTION CONTACT IN WORKING EXCURSION If we elect to provide group function on the working side, we should be aware that all teeth do not stay in excursive contact for the same length of stroke. As the mandible starts its move to the working side, all of the posterior teeth may contact in harmony with the anterior guidance and the condyle. As the mandible moves further to the side, the first teeth to disengage from contact are the most posterior molars. The disengagement is progressive, starting with the back molar, which has the shortest contact stroke, forward to the canine, which has the longest contact stroke 104 Balancing inclines must be relieved on all natural teeth regardless of the method used to record the border movements.

105. Types of posterior occlusal contours There are three basic decisions to make regarding the design of posterior occlusal contours: 1. Selection of the type of centric relation contacts 2. Determination of the type and distribution of contact in lateral excursions 3. Determination of how to provide stability to the occlusal form 105

106.   Occlusal considerations in full mouth rehabilitation There is no one type of occlusion that is optimum for all patients. The starting point in designing occlusal contours is to shape and locate the centric contacts so that the forces are directed parallel to the long axes of the teeth. Ideal occlusion can be defined as an occlusion compatible with the stomatognathic system, providing efficient mastication and good esthetics without creating physiologic abnormalities ( Hobo) 106

107. 107 Types of centric holding contacts Centric relation contact is usually established on restorations in one of three ways :

108. Types of centric holding contacts 108

109. Determinants of occlusal morphology Posterior controlling factor The steeper the articular eminence, the steeper path will the condyles follow during protrusion. It is a fixed factor. Anterior controlling factor The steeper the lingual surfaces of the maxillary anterior teeth, the steeper and more vertical will be the movement of the mandible. It is a variable factor and can be altered by the dental procedures. 109

110. Vertical determinants of occlusal morphology Anterior Guidance Condylar Guidance Distance of cusps from these controlling factors Plane of occlusion Curve of Spee Bennett movement – Amount, Direction and Timing Horizontal determinants of occlusal morphology It includes the relationship that influence the direction of ridges and grooves on the occlusal surface. Since the cusps pass between the ridges over grooves, the horizontal determinants also influence the placement of cusps Ridge and groove direction has the influence of the following factors Distance of tooth from axis of rotation Distance from mid-sagittal plane Bennett movement Intercondylar distance 110

111. Occlusal scheme Removable – distal extension Patient presents with Occlusal scheme Natural canine protected Canine protected Natural group function Group function Canine missing or periodontally weak Group function Opposing complete denture Balanced or monoplane Where no posterior tooth remaining Canine protected 111

112. Variations of posterior contact in lateral excursions 112 contacting inclines must be perfectly harmonized to border movements of the condyles and the anterior guidance . Convex-to-convex contacts cannot be used to accomplish this.

113. Anterior group function 1. It distributes wear over more teeth. 2. It distributes the stresses to more teeth. 3. It distributes stress to teeth that are progressively farther from the condyle fulcrum . convex lateral guidances make it difficult to accomplish. Canine-protected occlusion all lateral stresses must be resisted solely by the canine. capability of the canine to withstand the entire lateral stress load without any help from other teeth . Exquisitely sensitive nerve endings protect the canines against too much lateral stress by redirecting the muscles to more vertical function. 113

114. Occlusal equilibration in natural dentition The term ‘ occlusal equilibration’ refers to the correction of stressful occlusal contacts through selective grinding . It is a phase of treatment that eliminates only that part of tooth structure that is in the way of harmonious jaw function . Objectives Centric relation occlusion Acceptable disclusion of anterior teeth in harmony with condylar movement. Stability of occlusion Resolution of temperomandibular joint symptoms. Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.394 114

115. Equilibration procedures Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.395 115

116. 116 Interference to Centric Relation Centric interference can be differentiated into two types- Interference to arc of closure Interference to line of closure Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.396 As the condyles rotate on their centric relation axis, each lower tooth follows an arc of closure Primary interferences that deviate the condyle forward produce what is commonly called an anterior slide. primary interferences that cause the mandible to deviate to the left or the right from the first point of contact in centric relation to the most closed position

117. Note the freedom to close either in centric relation or in maximal intercuspation at the most closed vertical Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.397,398 Interferences to the arc of closure 117

118. Interference to the line of closure 1. If the interfering incline causes the mandible to deviate off the line of closure toward the cheek, grind the buccal incline of the upper or the lingual incline of the lower, or both inclines . 2. If the interfering incline causes the mandible to deviate off the line of closure toward the tongue, the grinding rule is: Grind the lingual incline of the upper or the buccal incline of the lower, or both inclines 118 Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.398,399

119. A balancing incline interference that would be easily missed if the condyles are not held firmly up on the centric relation axis during closure When the condyles are seated, the right molar is the only contact during closure. Squeezing the teeth together shifts the jaw to the right and causes the left condyle to displace. Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.399 119

120. Grinding Rules Rule 1: Narrow stamp cusps before reshaping fossae Rule 2: Don’t shorten a stamp cusp 120

121. Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.401 121

122. Dawson PE. Functional occlusion-e-book: from TMJ to smile design. Elsevier Health Sciences; 2006 Jul 31 . PAGE NO.401 Tilted teeth Tilted teeth or wide cusp tips can be adjusted to improve stability as well as to eliminate interferences. If the mark on the upper tooth is buccal to the central fossa, the buccal surface of 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. Grinding on the upper teeth only may mutilate upper cusps unnecessarily 122

123. Rule 3: Adjust centric interferences first 1. By adjusting centric interferences first, you have the option of improving cusp-tip position . 2. When cusp-tip position is given first priority, occlusal grinding is more evenly distributed to both arches . 3. If cusp-tip contours and position are improved first in centric relation, eccentric interferences can be eliminated with speed and simplicity. Rule 4: Eliminate all posterior incline contacts. Preserve cusp tips only. If all eccentric contacts on posterior teeth are to be eliminated, any posterior incline that marks in any excursion can be reduced. Centric stops must be preserved, but all other contacts can be shaped so that they are discluded by the anterior guidance. 123

124. Lateral excursion interferences The path that is followed by the lower posterior teeth as they leave centric relation and travel laterally is dictated by two determinants : 1. The border movements of the condyles, which act as the posterior determinant 2. The anterior guidance, which acts as the anterior determinant determine type of occlusion Group Function - posterior disclusion Cusp tips are centric holding stops hence adjustings to be done on fossa inclines 124

125. PROTRUSIVE INTERFERENCES Correction done in case of steep anterior guidance Grinding rule- DUML Materials for marking interference Ribbons Marking paper Joffe -marker waxes 125