Occlusion part/ orthodontic continuing education


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Occlusion part/ orthodontic continuing education

  1. 1. OCCLUSION (PART II) INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. CONTENTS 1.Concepts of occlusion 2.Optimum orthopaedically stable joint position 3.Optimum functional tooth contacts 4.Normal versus ideal occlusion www.indiandentalacademy.com
  3. 3. 5.Criteria for Optimum functional occlusion 6.Occlusal contact patterns a) Canine guided occlusion b) Group function occlusion 7.Summary 8.References www.indiandentalacademy.com
  4. 4. “What is the best functional relationship or occlusion of the teeth” ? www.indiandentalacademy.com
  5. 5. Concepts of occlusion Three occlusal concepts: The Gnathological The Freedom-in-centric European conceptual model www.indiandentalacademy.com
  6. 6. THE GNATHOLOGICAL CONCEPT •Mid 1920’s McCollum. Gnathology: exact science of mandibular movement and resultant occlusal contacts. Instruments: • Kinematic face bow, Gnathoscope and Gnathograph www.indiandentalacademy.com
  7. 7. Balanced occlusion:(complete dentures) “During functional excursions there is multiple simultaneous contacts present both on the working side and on the balancing side” Stallard and Stuart: organic or organised occlusion. -neglected that mastication is more vertical than lateral.www.indiandentalacademy.com
  8. 8. ARNE G. LAURITZEN Direction of occlusal stresses-long axis of teeth.  Centric relation=centric occlusion (condyles in uppermost and rearmost position) Simultaneous occlusal loads fall on as great number of teeth. Lateral excursion may be free. Canine guided occlusion. Group contact between upper and lower anterior teeth during protrusive movement.www.indiandentalacademy.com
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  10. 10. NILES GUICHET AND GNATHOLOGY Optimal occlusion (1966) Canine guided occlusion- biomechanics Occlusion must be in harmony with the mandibular movements of each patient. Ganathograph and Pantograph. Denar articulator. www.indiandentalacademy.com
  11. 11.  There is horizontal movement of the mandible from the maximal intercuspal position and teeth are capable of standing that horizontal stress in function .  (D’ Amicos)-canines - eight times stress than on the 2nd premolars. www.indiandentalacademy.com
  12. 12. VISION OF TRANSOGRAPHIC CONCEPT Page’s Four principles: 1.Opening axis 2.Cranial plane 3.Bennett movement 4.Envelope of motion 1. Opening axis:12º to 15º of rotation. Transverse hinge axis –reproducible. www.indiandentalacademy.com
  13. 13. 2.Cranial planes:No translatory condyles, so no practical support for horizontal plane. 3.Bennett movement: such a movement is because of mouth opening to 2 noncolinear axes, Page did not concede to the existence of the Bennett side shift. 4. In the discussions conceding the envelope of motion, when one takes the motions to a narrow functional terminal orbit, raised a great number of questions in the oral rehabilitation. www.indiandentalacademy.com
  14. 14. FREEDOM IN CENTRIC Posselt was first Functional occlusion- Ramfjord and Ash- 1970’s Criteria are to attempt to eliminate the need for neuromuscular adaptation. According to this concept, Maximum intercuspation and centric relation are coincident but flat areas on the depth of the fossae, on which opposing www.indiandentalacademy.com
  15. 15. cusps occlude, will allow for a certain degree of freedom in both centric and eccentric movements without the guiding influences of occlusal inclines. Vertical dimension of occlusion in maximum intercuspation and centric relation might be the same when all the interferences for closing in centric relation are eliminated. www.indiandentalacademy.com
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  18. 18. OCCLUSAL CONCEPTS OF SCHUYLER Correction of occlusal disharmonies in the natural dentition and to the concepts of freedom in centric and incisal guidance. According to Schuyler, Freedom in centric is a maxillomandibular position where maximum intercuspation and centric relation coincide to a certain degree of freedom for eccentric excursions without the influence of occlusal inclines.www.indiandentalacademy.com
  19. 19. Anteroposterior difference – 0.5 to 1 mm Variation in centric relation recording – not a point – area in relation to horizontal plane. Anterior guidance – Purpose: permit a condylar motion without restrictions along with the prevention of posterior contacts, during lateral excursions www.indiandentalacademy.com
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  21. 21. BEYRON’S OCCLUSAL CONCEPTS Based on functional convenience and avoidance of discomfort Most physiological inter-relationship between morphology and function might be the most natural one. Neuromuscular mechanism- protects teeth – excessive loads – protective reflex- important role in mandibular movement patterns.www.indiandentalacademy.com
  22. 22. PANKEY MANN PHILOSOPHY Monson’s sphere (occlusal line and plane) + Meyer’s concepts of a functionally generated path Pankey Mann Philosophy – oral rehabilitation Objectives:- optimal health, masticatory efficiency, comfort and esthetics Recently, Pankey Mann Schuyler concept (based on group function) www.indiandentalacademy.com
  23. 23. Stable and Static contacts - greatest number of teeth Long centric – Occlusal harmony with an anterior slide between centric relation and maximum intercuspation (1mm) and a small amount of lateral freedom for accommodation of the Bennett movement on the horizontal plane. Group function during lateral excursion (working side) Balancing side - No contacts Protrusion – Immediate disocclusionwww.indiandentalacademy.com
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  25. 25. DAWSON’S CONCEPT Peter Dawson  Manipulation of the jaw in centric relation (Bimanual technique)  Recording the border movements (Modification of functionally generated path technique) www.indiandentalacademy.com
  26. 26. Anterior guidance:  Anterior teeth are more capable of supporting stress than posteriors: (a)Position of anteriors (b)Higher density of bone (c)Longer roots, better crown : root ratio.  Theory of “Nutcracker” www.indiandentalacademy.com
  27. 27. GERBER’S CONDYLAR DISPLACEMENT THEORY European concept “ The normal or ideal occlusion was one in which the teeth would be in maximum intercuspation, with the condyles centered in the articular surfaces in the median and uppermost position. Any deviation related to this mandibular centralization constitutes a condylar displacement.” www.indiandentalacademy.com
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  29. 29. RAMFJORD AND ASH CONCEPTS OF OCCLUSION  Equilibrium between the different components of masticatory system.  Freedom for condyle movement  The occlusal concept applied should promote occlusal stability, does not exceed the needs and finances of most persons, is controlled by general clinician and does not need a specialized laboratory technician. www.indiandentalacademy.com
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  31. 31. Normal versus Ideal occlusion www.indiandentalacademy.com
  32. 32. Optimum orthopaedically stable joint position Centric relation, is the position of the mandible when the condyles are in an orthopaedically stable position. www.indiandentalacademy.com
  33. 33. Centric relation 1:The maxllomandibular relationship in which the condyles articulate with the thinnest avascular portion of their respective disks with the complex in the anterior–superior position against the shapes of the articular eminences.This position is independent of tooth contact. This position is clinically discernible when the mandible is directed superiorly and anteriorly. www.indiandentalacademy.com
  34. 34. It is restricted to a purely rotary movement about the horizontal axis(GPT- 5). 2:The most retruded physiologic relation of the mandible to the maxillae to and from which the individual can make lateral movements.It is a condition that can exist at various degrees of jaw separation.It occurs around the terminal hinge axis(GPT-3). www.indiandentalacademy.com
  35. 35. 3:The most retruded relation of he mandible to the maxillae when the condyles are in the most posterior unstrained position in the glenoid fossae from which lateral movement can be made , at any given degree of jaw separation(GPT-1). 4:The most posterior relation of the lower to the upper jaw from which lateral movement can be made at a given vertical dimension(Boucher). www.indiandentalacademy.com
  36. 36. 5:A maxilla to the mandible relationship in which the condyles and the disks are thought to be in the midmost,uppermost position.The position has been difficult to define anatomically but is determined clinically by assessing when the jaw can hinge on a fixed terminal axis (upto 25mm).It is clinically determined relationship of the mandible to the maxilla when the condyle–disk assemblies are positioned in their most superior position in the mandibular fossae and against the distal slope of the articular eminence(ash).www.indiandentalacademy.com
  37. 37. 6:The relation of the mandible to the maxillae when the condyles are in the uppermost and the rearmost position in the glenoid fossae.This position may not be able to be recorded in the presence of dysfunction of the masticatory system. 7: A clinically determined position of the mandible placing both the condyles into their anterior uppermost position.This can be determined in patients without pain or derangement in the TMJ (Ramfjord) www.indiandentalacademy.com
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  39. 39. Centric relation has been described in three different ways: anatomically, conceptually, and geometrically. Anatomical: It is the position of the mandible to the maxilla, with the intra-articular disc in place when the head of the condyle is against the most superior part of the distal facing incline of the glenoid fossa.This can be paraphrased uppermost and foremost. www.indiandentalacademy.com
  40. 40. Conceptual: It is that position of the mandible relative to the maxilla, with the articular disc in place, when the muscles that support the mandible are in their most relaxed and least strained position. Geometrical: It is the position of the mandible relative to the maxilla,with the intra- articular disc in place, when the head of the condyle is in terminal hinge axis.www.indiandentalacademy.com
  41. 41. Dawson’s concept Gelb’s concept www.indiandentalacademy.com
  42. 42. Optimum functional tooth contacts Closure in CR Creates an unstable occlusion Neuromuscular system Feed back muscles Mandibular position More stable occlusionwww.indiandentalacademy.com
  43. 43. Musculoskeletal stable position Stable occlusal condition HARMONY www.indiandentalacademy.com
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  46. 46. Conclusion: Optimum occlusal conditions during mandibular closure would be provided by even and simultaneous contact of all posterior teeth. www.indiandentalacademy.com
  47. 47. Criteria for optimum functional occlusion Even and simultaneous contact of all possible teeth when the mandibular condyles are in their most superoanterior position, resting against the posterior slopes of the articular eminences, with the discs properly interposed.www.indiandentalacademy.com
  48. 48. Occlusal contact patterns Direction of force Amount of force www.indiandentalacademy.com
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  51. 51. Criteria for optimum functional occlusion First - Even and simultaneous contact of all possible teeth + centric relation Second – each tooth should contact in such a manner that the forces of closure are directed through the long axis of the teeth.www.indiandentalacademy.com
  52. 52. Nutcracker theory www.indiandentalacademy.com
  53. 53. Canine guided occlusion www.indiandentalacademy.com
  54. 54. Group function occlusion www.indiandentalacademy.com
  55. 55. Buccal to buccal cusp contacts are desirable No non-working side contacts www.indiandentalacademy.com
  56. 56. Protrusive contacts www.indiandentalacademy.com
  57. 57. Postural considerations and functional tooth contacts Depends on head position In the alert feeding position, as well as in the normal upright position, the posterior teeth should contact more heavily than the anterior teeth (mutually protected occlusion). www.indiandentalacademy.com
  58. 58. Summary 1.When the mouth closes, the condyles are in their most superoanterior (Musculoskeletal stable) position, resting on the posterior slopes of the articular eminences with the discs properly interposed. In this position there is even and simultaneous contact of all posterior teeth. The anterior teeth also contact but more lightly than the posterior teeth. www.indiandentalacademy.com
  59. 59. 2. All tooth contacts provide axial loading of occlusal forces. 3. When the mandible moves into a laterotrusive position, there are adequate tooth-guided contacts on the laterotrusive (working) side to disocclude the mediotrusive (nonworking) side immediately. The most desirable guidance is provided by the canines (canine guidance). www.indiandentalacademy.com
  60. 60. 4. When the mandible moves into a protrusive position, there are adequate tooth-guided contacts on the anterior teeth to disocclude all posterior teeth immediately. 5. In the alert feeding position, posterior tooth contacts are heavier than anterior tooth contacts. www.indiandentalacademy.com
  61. 61. REFERENCES  Occlusion series in BDJ, 2001;191:6-7  Okeson JP. Management of Temporomandibular Disorders and Occlusion, ed. 4th , 1998; Mosby  Ash MM and Ramfjord S. Occlusion, ed. 4th , 1966; WB Saunders Company, Michigan www.indiandentalacademy.com
  62. 62. Santos JD. Occlusion Principles and Concepts, ed. 2nd , 1999; Ishiyaku EuroAmerica, Inc. U.S.A.  Shillingburg HT. Fundamentals of Fixed Prosthodontics, ed.3rd , 1997;Quintessence www.indiandentalacademy.com
  63. 63. www.indiandentalacademy.com
  64. 64. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com