Occlusion Chapter 20

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.

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

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

Stages of Development Deciduous dentition Mixed dentition Permanent dentition

Deciduous Teeth Primate spaces Leeway space Diastemas www.coveringkids.org. Access, August 2002, p. 9.

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.

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.

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.

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

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. 1993. p. 439.

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

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

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

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.

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

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

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

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

Mesial Drift Tooth moves forward (not mesioversion)

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

Infraversion Wright. A Textbook of Orthodontics. Second Edition.1995. Great Britain, Redwood Books, p. 219.

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

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

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

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

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

Anterior Openbite

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

Openbite Due to a Tongue Thrust

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

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.

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

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

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

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

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

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

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

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

Normal Perfect occlusion!!!!

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)

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

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

Class II Malocclusion 11 22

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

Class III 14 11 19 22

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

Class III Malocclusion 11 22

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.

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. 2003, p. 57.