Hygiene Atlas

Atlas · Plate II · Dental Anatomy and Tooth Morphology · 09

Occlusion

Occlusion is how the arches meet. In Angle Class I the mesiobuccal cusp of the maxillary first molar sits in the buccal groove of the mandibular first molar; in Class II the mandibular molar is distal to that spot, and in Class III it is mesial. Normal overjet and overbite are each about 2-3 mm, and the curves of Spee and Wilson shape the occlusal plane.

High-yield facts · 7

  1. Angle Class I: the MB cusp of the maxillary first molar sits in the buccal groove of the mandibular first molar.T6
  2. Angle Class II: the mandibular molar is distal to that position (retrognathic profile). Division 1 has flared maxillary incisors; Division 2 has retroclined centrals.T6
  3. Angle Class III: the mandibular molar is mesial (prognathic profile).T6
  4. Normal overjet (horizontal) and overbite (vertical) are about 2-3 mm, or about 20-30% overlap for overbite.T6
  5. Curve of Spee is the anteroposterior curve of the occlusal plane; curve of Wilson is the side-to-side curve.T6
  6. Primary molar terminal planes: flush, mesial step (favors Class I) and distal step (leads to Class II).S43
  7. Centric occlusion is maximum intercuspation; centric relation is a bone-braced condyle position independent of tooth contact.T6

Facts are written in our own words; each tag links to its source. Values marked "sources vary" differ between references, so check the one your program uses.