1. Occlusion
Chapter 20

2. Definition
Occlusion is defined as the relationship of the maxillary and mandibular teeth when closed together or during excursion of movement when teeth are touching.

3. Importance of Assessing Occlusion
Personalized instruction
Thumbsucking
Orthodontics
Fixed or partial appliances
Adaptation of oral hygiene technique
Diagnosis of dental disease
Recording occlusion for legal records and forensics

4. Importance of Good Occlusion
Good masitication
Facial symmetry
Promote normal speech
Stability of jaw relationships

5. Stages of Development Deciduous dentition Mixed dentition
Permanent dentition

6. Deciduous Teeth Primate spaces Leeway space Diastemas
Access, August 2002, p. 9.

7. Primate Spaces
Spaces that occur in the primary dentition that are isolated to:
Maxillary anterior to canines
Mandibular posterior to canines
Brand and Isselhard. Anatomy of Orofacial Structures, 7th Ed. Mosby, St. Louis. 2003, p. 67.

8. Leeway Space
Extra space that is gained upon the exfoliation of the deciduous canines and molars.
These deciduous teeth occupy this space, which is a wider distance than the permanent replacements.
Brand and Isselhard. Anatomy of Orofacial Structures, 7th Ed. Mosby,
St. Louis. 2003, p. 56.

9. Diastema
Spaces between primary teeth that allow room for the permanent teeth to erupt
Diastemas may be isolated between the incisors with growth and development.

10. Static Occlusion
The relationship of the teeth when the jaws are closed in centric occlusion.
Maximum cuspation

11. Centric Occlusion
The relationship of opposing occlusal surfaces which provides the maximum contact and /or intercuspation.
Habitual occlusion
Facial view
Ash. Wheeler’s Dental Anatomy, Physiology and Occlusion., Seventh Edition.
W. B. Saunders Company, Philadelphia p. 439.

12. Centric Relation
The most unstrained, retruded anatomic and functional position of the heads of the condyles of the mandible in the glenoid fossae of the TMJ

13. Functional Occlusion Teeth contact while the mandible is working.
Examples: chewing, swallowing

14. Keys to Understanding The maxilla is stationary.
The mandible is movable (static).

15. Keys to Understanding
The maxilla slightly overlaps the mandibular arch in normal occlusion.
The mesiobuccal (buccal) groove of the mandibular first molar and the mesiobuccal cusp tip of the maxillary 1st molar are occluding in normal occlusion.

16. Single Tooth Deviations
Labioversion/Buccoversion
Linguoversion
Torsoversion (Mesioversion and Distoversion)
Supraversion
Infraversion

17. Linguoversion Maxillary central is linguoverted.
Proffit. Contemporary Orthodontics, Second Edition. Mosby, St. Louis. 1993, p. 8.

18. Labioversion/Buccoversion
Lavioversion: anterior tooth toward the lip
Buccoversion: posterior tooth toward the
buccal mucosa
Buccoversion
Labioversion

19. Torsoversion Mesioversion: mesial toward the buccal mucosa or lip
Distoversion: distal toward the buccal mucosa or lip
Distoversion
Mesioversion

20. Mesial Drift
Tooth moves forward (not mesioversion)

21. Supraversion (Supraeruption)
Hypereruption due to no opposing tooth
Brand and Isselhard. Anatomy of Orofacial Structures, 7th Ed. Mosby,
St. Louis. 2003, p. 67.

22. Infraversion
Wright. A Textbook of Orthodontics. Second Edition Great Britain,
Redwood Books, p. 219.

23. Groups of Teeth Crossbite Edge to edge End to end Openbite Overjet
Anterior
Posterior
Edge to edge
End to end
Openbite
Overjet
Underjet

24. Anterior Crossbite Crossbite of 10 year old
Proffit. Contemporary Orthodontics, Second Edition. Mosby, St. Louis. 1993, p. 152.

25. Posterior Crossbite
Proffit. Contemporary Orthodontics, Second Edition. Mosby, St. Louis. 1993, p. 8.

26. End to End Posterior teeth do not overlap vertically 5 29
Proffit. Contemporary Orthodontics, Second Edition. Mosby, St. Louis. 1993, p. 8.

27. Openbite No vertical overlap. The separation is measured.
Proffit. Contemporary Orthodontics, Second Edition. Mosby, St. Louis. 1993, p. 8.

28. Anterior Openbite

29. Posterior Openbite Left posterior (lateral) openbite
Wright. A Textbook of Orthodontics. Second Edition.1995, Great Britain,
Redwood Books, p. 218.

30. Openbite Due to a Tongue Thrust

31. Overjet Horizontal overlap Of the incisors Measure distance
with a probe.
Proffit. Contemporary Orthodontics, Second Edition. Mosby, St. Louis. 1993, p. 8.

32. Overjet: Thumbsucking
Casts of 11 year old twins. The cast to the left continued to suck thumb several hours a day. The cast on the right quit at age 6.

33. Overbite Overbite : Vertical overlap
Proffit. Contemporary Orthodontics, Second Edition. Mosby, St. Louis. 1993, p. 8.

34. Overbite Vertical of the incisors Normal Moderate Severe
Brand and Isselhard. Anatomy of Orofacial Structures, 7th Ed. Mosby, St. Louis. 2003, p. 61.

35. Skeletal Profiles Mesiognathic: Class I Retrognathic: Class II
Prognathic: Class III

36. Skeletal Profiles Mesiognathic: Class I
Proffit. Contemporary Orthodontics, Second Edition. Mosby, St. Louis. 1993, p. 147.

37. Skeletal Profiles Retrognathic: Class II
Proffit. Contemporary Orthodontics, Second Edition. Mosby, St. Louis. 1993, p. 147.

38. Skeletal Profiles Prognathic: Class III
Proffit. Contemporary Orthodontics, Second Edition. Mosby, St. Louis. 1993, p. 147.

39. Angle’s Classification
Normal Occlusion
Malocclusions
Class I
Class II
Division 1
Division 2
Class III

40. Normal or Class I Mesiobuccal groove of the mandibular 1st molar
and the mesiobuccal cusp tip of the maxillary 1st
molar are aligned.
mesiobuccal cusp tip
mesiobuccal groove

41. Normal
Perfect occlusion!!!!

42. Class I Malocclusion One or more teeth deviate from normal occlusion.
In the picture, some anterior teeth are torsoverted. Molar relationship is in normal alignment. (Class I, #22, #23 and #26 mesioverted)

43. Class II Malocclusion
The mesiobuccal groove of the mandibular 1st molar is distal to the mesiobuccal cusp tip of the maxillary 1st molar.
mesiobuccal cusp tip
mesiobuccal groove

44. Class II: Division 1 and 2 Division 1: Anterior teeth flare out
Division 2: Anterior teeth retrude

45. Class II Malocclusion 11 22

46. Class III Malocclusion
Mesiobuccal groove of the mandibular 1st molar is mesial to the mesiobuccal cusp tip of the maxillary 1st molar.
mesiobuccal cusp tip
mesiobuccal groove

47. Class III 14 11 19 22

48. Class III Malocclusion
Courtesy of Baker College of Port Huron’s Dental Hygiene Clinic

49. Class III Malocclusion11 22

50. Curve of Wilson
Right to left in a posterior view: transverse occlusal curve
Brand and Isselhard. Anatomy of Orofacial Structures, 7th Ed. Mosby, St. Louis. 2003, p. 57.

51. Sphere of Monson
Curve of Wilson and Spee viewed simultaneously demonstrate sphere of Monson
Brand and Isselhard. Anatomy of Orofacial Structures, 7th Ed. Mosby, St. Louis , p. 57.