Occlusal plane/ orthodontic seminars


Published on

Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.

Published in: Education
1 Comment
No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Occlusal plane/ orthodontic seminars

  1. 1. OCCLUSAL PLANE IN ORTHODONTICS www.indiandentalacademy.com
  4. 4. INTRODUCTION In orthodontics various planes are used as reference planes in diagnosis and treatment planning The occlusal plane in being the plane of dentition occupies a prime position in cephalometrics ,treatment mechanics www.indiandentalacademy.com
  5. 5. DEFINITION-various authors  Enlow: Occlusal plane “A line passing through one half of the cusp heights of the first permanent molars and one half of the overbite of the incisors” Functional occlusal plane A horizontal line from the posterior most occlusal contact of the last fully erupted mandibular molars extending anteriorly to the anterior most occlusal contact of the fully erupted premolars www.indiandentalacademy.com
  6. 6. CHACONAS: “Denture plane which bisects the posterior occlusion of the permanent molars and premolars and extends anteriorly” www.indiandentalacademy.com
  7. 7. DOWN”S: Occlusal plane is the line bisecting the overlapping cusps of the first molars and incisor overbite www.indiandentalacademy.com
  8. 8. OKASON: The plane of occlusion is an imaginary line touching the incisal edges of the maxillary anterior teeth and the cusps of the maxillary posterior teeth www.indiandentalacademy.com
  9. 9. HARVOLD: Defines the functional occlusal plane as the line which represents the functional table of occlusion in the first permanent molar, second pre molar and first pre molars areas The level and inclination of the functional occlusal plane is the result of the neuro muscular growth and developmental forces acting on the dentition www.indiandentalacademy.com
  10. 10. SIGNIFICANCE OF OCCLUSAL PLANE The configuration of the occlusal plane is important as slight variations will lead to occlusal instability. It should be in harmony with other components of the masticatory system. It forms the basis by which occlusal surfaces of teeth can be related to one another and to other structures of the head. www.indiandentalacademy.com
  11. 11. OCCLUSAL PLANE Occlusal plane or plane of occlusion refers to a imaginary surface that theoretically touches the incisal edges of the incisors and the tips of the occluding surfaces of the posterior teeth. www.indiandentalacademy.com
  12. 12. OCCLUSAL CANT It is defined as the rotation of the object in its longitudinal plane. www.indiandentalacademy.com
  13. 13. OCCLUSAL LINE By definition a line is one which connects two points in space Occlusal line refers to the line connecting the overlap of the first permanent molars and incisors In orthodontics the terms occlusal plane and occlusal line are used interchangingly and can mean one or the other www.indiandentalacademy.com
  14. 14. Different occlusal planes  Thayers in 1990 AJO has given three different occlusal planes.they are Bisected occlusal plane Functional occlusal plane Lower incisor occlusal plane Upper occlusal plane Lower occlusal plane www.indiandentalacademy.com
  15. 15. BISECTED OCCLUSAL PLANE Occlusal plane in this case refers to a bisecting line through overlap of distobuccal cusps of first permanent molars and incisors www.indiandentalacademy.com
  16. 16. FUNCTIONAL OCCLUSAL PLANE The functional occlusal plane refers to the line bisecting the molars and premolars It passes posteriorly through the Xi point Anteriorly it passes slightly below the lip embrasure www.indiandentalacademy.com
  17. 17. LOWER INCISOR OCCLUSAL PLANE Lower incisor occlusal plane refers to line drawn from bi section of distobuccal cusps of first permanent molars to tip of lower incisor www.indiandentalacademy.com
  18. 18. Upper occlusal plane connects the incisal edges of the the upper central incisors with a point 0.5 mm occlusal to the mesiobuccal cusp tip of the first permanent molar Lower occlusal plane connects the incisal edges of the lower central incisors with a point 0.5 mm occlusal to the mesiobuccal cusp tip of the first permanent molar www.indiandentalacademy.com
  19. 19. Esthetic plane of occlusion The upper incisor lies commonly 3mm below a relaxed upper lip. So a line joining this point and distobuccal cusp tip of the upper first molar represents the esthetic occlusal plane www.indiandentalacademy.com
  20. 20. Treatment plane of occlusion There are two occlusal planes ,the upper and lower .The treatment occlusal plane may take either as the reference or a compromise plane can be taken depending on the utility to the patient www.indiandentalacademy.com
  21. 21. Factors determining treatment plane of occlusion Natural plane of occlusion Esthetic plane of occlusion Distribution of alveolar process A-B difference to plane of occlusion www.indiandentalacademy.com
  22. 22. Natural plane of occlusion Maintain a good posterior occlusion which already exists Changing the occlusal plane would alter the axial inclinations of teeth which might affect stability So the treatment plane of occlusion should alter axial inclinations minimally www.indiandentalacademy.com
  23. 23. Esthetic plane of occlusion When the esthetic plane of occlusion does not coincide with natural plane of occlusion,a decision as to which plane should be taken as treatment plane should be decided www.indiandentalacademy.com
  24. 24. Distribution of alveolar process The distribution of alveolar process in the upper and lower arches can be described as a ratio of the distance from the lower incisor to Me in relation to the distance from ANS to Me. This ratio is about 0.61 www.indiandentalacademy.com
  25. 25. Altering the occlusal plane and its effect on A-B differenceThe AB difference varies with the cant of the occlusal plane. The occlusal plane maybe flat or steep. www.indiandentalacademy.com
  26. 26. Extent of the occlusal plane APOcc – ANTERIOR POINT FOR THE OCCLUSAL PLANE A constructed point, the mid point of the incisor overbite in occlusion www.indiandentalacademy.com
  27. 27. Extent of the occlusal plane PPOcc – POSTERIOR POINT FOR THE OCCLUSAL PLANE A constructed point, the most distal point of contact between the most posterior molars in occlusion www.indiandentalacademy.com
  28. 28. OCCLUSAL CURVES  Curve of spee  Curve of wilson  Curve of monson www.indiandentalacademy.com
  29. 29. CURVE OF SPEE Introduced by graph von spee Is an anteroposterior curve extending from the tip of the mandibular canine along the buccal cusp tips of the mandibular posterior teeth www.indiandentalacademy.com
  30. 30. If the curve is extended, it would form a circle of about 4 inches diameter The curve results from variations in axial alignment of lower teeth. The long axis of the each lower teeth is aligned nearly parallel to its individual arc of closure around the condylar axis This requires a gradual progressive increased mesial tilting of the teeth towards molars which creates the curve of spee www.indiandentalacademy.com
  31. 31. FACTORS AFFECTING THE CURVE OF SPEE Degree of curve Orientation of curve www.indiandentalacademy.com
  32. 32. DEGREE OF CURVE When the radius of the curve is longer, a flat plane of occlusion is present. www.indiandentalacademy.com
  33. 33. When the radius of the curve is shorter, an acute plane of occlusion is present www.indiandentalacademy.com
  34. 34. ORIENTATION OF THE CURVE OF SPEE Refers to the relationship of its radius to a horizontal reference plane Also influences how the height of the individual posterior teeth is affected thereby affecting the acuity of the plane of occlusion www.indiandentalacademy.com
  35. 35. Radius perpendicular to a horizontal reference plane Posterior teeth located distal to the radius need shorter cusps than those located mesial to the radius www.indiandentalacademy.com
  36. 36. If the plane of occlusion is rotated more posteriorly All the posterior teeth can have shorter cusps as they are positioned distal to the perpendicular from the reference plan www.indiandentalacademy.com
  37. 37. If the plane of occlusion is rotated more anteriorly All the posterior teeth can have taller cusps as they are positioned mesial to the perpendicular from the reference plan www.indiandentalacademy.com
  38. 38. CURVE OF WILSON A curve that contacts the buccal and lingual cusp tips of the mandibular buccal teeth It is mediolateral on each side of the arch www.indiandentalacademy.com
  39. 39. CURVE OF WILSON Teeth are aligned parallel to the medial pterygoid for optimum resistance to masticatory stresses The elevated buccal cusps prevent food from going past the occlusal table www.indiandentalacademy.com
  40. 40. CURVE OF MONSON It is a curve obtained by extending the curve of spee and curve of wilson to all cusps and incisal edges. www.indiandentalacademy.com
  41. 41. CANT OF THE OCCLUSAL PLANE 1997 AJO - Stanley Braun, DDS, MME, and Harry L. Legan, DDS Changes in occlusion related to the cant of the occlusal plane www.indiandentalacademy.com
  42. 42.  Dental occlusion is influenced by changes in the cant of the occlusal plane.  As a general clinical guide, each degree of rotation of the occlusal plane will result in a half millimeter change in the dental occlusal relationship.  This is of importance, because changes in the cant of the occlusal plane are sometimes unintentional, as well as intentional, during orthodontic therapy.  An earlier study has also documented that the occlusal plane rotates naturally upward and forward approximately 6° during growth and development. www.indiandentalacademy.com
  43. 43. when the occlusal plane is rotated downward and backward (steepened—as seen in the sagittal plane), a Class II dental occlusion will approach a Class I relation. This rotation may be achieved by the use of Class II elastics. On the other hand, when the occlusal plane is rotated upward and forward (flattened), a Class III dental occlusion will tend toward Class I. This can be achieved through Class III elastic wear. www.indiandentalacademy.com
  44. 44. METHODS AND MATERIALS For purposes of this study, the occlusal plane as defined by Downs has been used. (The plane extends from the midpoint of a line connecting the anterior cusp tip of the mandibular first molar to the anterior cusp tip of the maxillary first molar, posteriorly, to the midpoint of a line connecting the incisal tip of the mandibular central incisor to the incisal tip of the maxillary central incisor, anteriorly.) www.indiandentalacademy.com
  45. 45. It is assumed the maxillary and mandibular dental arches each rotate about a point approximating their respective centers of resistance. This is also true for a group of teeth joined together by a relatively stiff arch wire. The group will rotate about a point approximating its combined center of resistance. www.indiandentalacademy.com
  46. 46. The center of resistance for the arch viewed in the sagittal plane is located as follows: in the maxilla, 1.53 mm anterior to the first premolar distal contact and 14.20 mm perpendicular and apical to its occlusal surface www.indiandentalacademy.com
  47. 47. The center of resistance for the arch viewed in the sagittal plane in the mandible, 1.25 mm anterior to the first premolar distal contact and 14.24 mm perpendicular and apical to its occlusal surface. www.indiandentalacademy.com
  48. 48. The dimensional relationships in the maxillary arch along the occlusal plane resulting from a downward and backward rotation of the occlusal plane.A similar coordinate dimensional relationships in the mandibular arch resulting from the same downward and backward rotation of the occlusal plane. www.indiandentalacademy.com
  49. 49. The derived relationships were used to calculate occlusal articulation changes corresponding to angular changes of the occlusal plane in the sagittal plane in both downward and backward and upward and forward directions in one degree increments from 0° to 12°. There is an approximately 0.5 mm change in the occlusal relationship for each degree of occlusal plane rotation in either downward and backward or upward and forward directions. www.indiandentalacademy.com
  50. 50. Inference of the study This study reveals that small changes in the cant of the occlusal plane significantly effect dental occlusion. As an example, if the premolars are in an end-on Class II relation, a 7.2° downward and backward rotation (steepening) of the occlusal plane will result in a change to Class I occlusion Correspondingly, if the premolars exhibit a Class III relationship, an upward and forward rotation (flattening) of 7.2° will result in a change to Class I occlusion. www.indiandentalacademy.com
  51. 51. From a clinician's viewpoint, a general guide that may be used is for each degree of occlusal plane angular change, a half millimeter change in occlusion results. It is apparent that small angular differences (intentional or unintentional during orthodontic treatment) will result in significant alterations in occlusion. www.indiandentalacademy.com
  52. 52. OCCLUSAL PLANE IN DIAGNOSIS In cephalometrics Down’s analysis. Steiner’s analysis. Witt’s analysis. Sassouni’s analysis. COGS analysis. Proportional analysis. www.indiandentalacademy.com
  53. 53. DOWN’S ANALYSIS Reference plane – FH plane OCCLUSAL PLANE A line bisecting the occlusion of the first molars and central incisors. Should either incisor lack full eruption or be in supra occlusion the occlusion plane is determine by the pre molars. Mean - 9.3 degrees ± 3 www.indiandentalacademy.com
  54. 54. www.indiandentalacademy.com
  55. 55. STEINER’S ANALYSIS. Reference plane – SN plane OCCLUSAL PLANE A line bisecting the overlap of molars and the incisor overbite. Mean – 14.5 ± 2 degree www.indiandentalacademy.com
  56. 56. Witt’s analysis. Reference line – functional occlusal plane Occlusal plane - the line bisecting the molars and pre molar overlapswww.indiandentalacademy.com
  57. 57. SASSOUNI’S ANALYSIS In this analysis , the occlusal plane is the bisector of molar and incisor overbite Mean Upper occ plane angle-9 deg Lower occ plane angle-15 deg www.indiandentalacademy.com
  58. 58. COGS analysis In this analysis the upper and lower occlusal plane are drawn seperately REFERENCE PLANE –true horizontal Mean values Upper occ plane--6.2±5.1 deg www.indiandentalacademy.com
  59. 59. Proportional analysis.Developed by koski and Virolainon in 1965 Based on comparison of the various angles to establish relations between separate parts of the skeleton REFERENCE PLANES op-n & op-pog Values are given in percentages www.indiandentalacademy.com
  60. 60. Occlusal plane during treatment -upper-Lowering the upper occlusal plane In patients with vertical maxillary deficiency,the occlusal plane can be lowered with the use of a cervical headgear with outer bows bent upward Elastics may also be used opposite to cRES to avoid rotation between the archeswww.indiandentalacademy.com
  61. 61. RAISING THE UPPER OCCLUSAL PLANE Occipital head gear pull thro cres to get entire upper jaw “ankylosed”. When genuine intrusion is needed lefort I is indicated www.indiandentalacademy.com
  62. 62. FLATTENING THE UPPER OCCLUSAL PLANE Class III elastics Vertical elastics thro cres of upper jaw Occipital head gear with short outer bow(ant to C resof upper jaw) Combination type head gear with occi pull> cervical pull) www.indiandentalacademy.com
  63. 63. STEEPENING THE OCCLUSAL PLANE ROBIN HOOD TYPE OF HEAD GEAR used in Anterior open bites upper lip length redundencies cleft lip & palate patients www.indiandentalacademy.com
  64. 64. Use of class II Elastics and a cervical pull head gear www.indiandentalacademy.com
  65. 65. Vertical elastics anterior to the C RES of the upper jaw combined with cervical head gear to the lower jaw with anterior hooks and a short outer bow www.indiandentalacademy.com
  66. 66. Occipital head gear with long outer bow Effective in treatment of open bites www.indiandentalacademy.com
  67. 67. CHANGES IN LOWER OCCLUSAL PLANE DURING TREATMENT Lowering the lower occlusal plane A cervical head gear thro C RES of lower arch will hold the lower arch or intrude it www.indiandentalacademy.com
  68. 68. Raising the lower occlusal plane eruption usually occurs without any orthodontic intervention when entire arch requires active eruption vertical elastics can be used www.indiandentalacademy.com
  69. 69. Flattening the lower occlusal plane cervical head gear to lower arch with outer bow bent upward www.indiandentalacademy.com
  70. 70. Steepening the lower occlusal plane Cervical pull head gear ,with point of force application anterior to the C RES of the lower jaw www.indiandentalacademy.com
  71. 71. CONTROLLING THE DIFFERENCE IN OCCLUSAL PLANES BETWEEN RIGHT AND LEFT SIDES DURING TREATMENT Many a time the natural plane of occlusion on one side is different from the other side One of these planes will be chosen over the other as the treatment plane of occlusion It is therefore necessary to rotate the other plane of occlusion to the treatment plane www.indiandentalacademy.com
  72. 72. www.indiandentalacademy.com
  73. 73. ASSESSMENT OF RETRACTION USING THE OCCLUSAL PLANE AS A GUIDE In a group A anchorage case,retraction of anterior teeth is done in two stages stage 1 – controlled tipping stage 2 – root movement www.indiandentalacademy.com
  74. 74. The picture shows the relationship of the incisal edges of the anterior segment and the upper natural occlusal plane This is what one should see clinically if correct incisor root position is achieved Stage 1 www.indiandentalacademy.com
  75. 75. Stage 2 During the enmasse root retraction stage, the entire anterior segment is rotated about the CROT very close to the incisal edges or brackets of the anterior teeth The occlusal plane once again is levelled www.indiandentalacademy.com
  76. 76. In group B cases, both the anterior and the posterior segments can be moved towards each other in a translatory fashion The forces must be equal and opposite for this equal attraction The natural occlusal plane remains level and does not change www.indiandentalacademy.com
  77. 77. In group C cases, the protraction of the posterior segments is needed The forces are kept high Second premolars are extracted Two stage protraction stage 1 –controlled tipping of buccal segment stage 2 –root uprighting www.indiandentalacademy.com
  78. 78. Stage 1 controlled tipping of the buccal segment occurs which leads to the lifting of that part of occlusal plane www.indiandentalacademy.com
  79. 79. Stage 2 Root uprighting stage leads to levelling of the occlusal plane to the natural plane of occlusion www.indiandentalacademy.com
  80. 80. OCCLUSAL PLANE SUBSTITUTES 1994 AJO – Hall & scott The maxillary-mandibular planes angle (MM°) bisector: A new reference plane for anteroposterior measurement of the dental bases www.indiandentalacademy.com
  81. 81. MM Bisector www.indiandentalacademy.com
  82. 82. A new plane, geometrically derived from the dental base planes, has been tested as an occlusal plane substitute for the measurement of anteroposterior jaw relationships. It lies close to but at an angle and inferior to the traditional occlusal planes and is highly reproducible at all times. www.indiandentalacademy.com
  83. 83. Lateral cephalograms 36 young adults (25 men and 11 women) 43 – 10- to 12-year-old children (24 girls and 19 boys) Wits technique of anteroposterior measurement was used to compare A-B values measured to the MM bisector  functional occlusal plane (FOP) Bisecting occlusal plane (BOP). www.indiandentalacademy.com
  84. 84. Because of the downward cant of the bisector anteriorly, B is projected onto it ahead of A in normal occlusion and coincides with A in skeletal (2) malocclusion. Mean values for normal occlusion were found to be approximately – 4 mm for the children ( – 4.2 mm girls and – 4.0 mm boys) 4.5 mm for the adults ( – 4 mm women and – 4.7 mm men). www.indiandentalacademy.com
  85. 85. In this study, the FOP moved in an upward and forward direction, opposite to that of the jaws, with age. This meant that the mean value of the Wits measurement in the children's group (– 2.65 mm, indicated a skeletal 3 tendency) changed to 0 mm, measured in the adult group, suggesting a marked decrease in mandibular prognathism with age. This was contradicted by ANB° values for the two groups, which indicated a slight increase in prognathism with age. www.indiandentalacademy.com
  86. 86. The BOP, on the other hand, moved in a downward and backward direction, the same as the jaws, Wits measurements made to this plane, in fact, showed a difference between the two groups (approximately 1 mm) that changed from a negative value in the children's group to a positive value in the adult group, which seemed to suggest a slight decrease in jaw prognathism with maturity, again a result at variance with the ANB° values for the two groups. www.indiandentalacademy.com
  87. 87. The MM° bisector is the summary of the maxillary and the mandibular base plane angulations, and its rotation, when measured as an angle to the PM vertical, will reflect the direction and the amount of the total growth rotation of the whole dental complex. In this study, it was a downward and backward rotation of 2°, However, Wits values measured between A and B, projected onto this plane, differed very little with age. www.indiandentalacademy.com
  88. 88. A and B move with the dental bases, the same amount and direction, and so clearly their true AP relationship was being effectively measured when measuring to this plane, free of the "change of cant" distortion. Mean values children's group– 4 mm adults group – 4.5 mm, suggesting a slight increase in prognathism with age that is in agreement with the ANB° findings for the two groups. www.indiandentalacademy.com
  89. 89. Conclusion Occlusal plane in the perspective not only acts as a reliable plane in making a good diagnosis but also ensures a correct progress in treatment when constantly monitored So a clinician should always check the occlusal plane to know if he is heading the right way to the finish www.indiandentalacademy.com
  90. 90. For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com