Resident Manual of Trauma to the Face, Head and Neck

Chapter 5: Mandibular Trauma

6. Overjet and Overbite Overjet is anterior vertical overlap, and overbite is anterior horizontal overlap. Both are measured in millimeters. 7. Skeletal Malocclusion Skeletal disharmony of the maxillary and mandibular relationship, as identified on cephalometric assay, produces malocclusion of the upper and lower dentition. Most skeletal malocclusions can only be treated by orthognathic surgery. 8. Dental Malocclusion Dental malocclusion is the misalignment of teeth or incorrect relation between the teeth of the maxilla and mandible. This term was coined by Edward Angle, the “father of modern orthodontics,” as a derivative of occlusion, which refers to the way opposing teeth meet. Most dental malocclusions are treated by orthodontic movement. 22 9. Mesial Mesial refers to the direction toward the anterior midline in a dental arch. Each tooth can be described as having a mesial surface and, for posterior teeth, a mesiobuccal and a mesiolingual corner or cusp. 10. Distal Distal refers to the direction toward the last tooth in each quadrant of a dental arch. Each tooth can be described as having a distal surface and, for posterior teeth, a distobuccal and a distolingual corner or cusp. 11. Crossbite A crossbite is a malocclusion where a single tooth or a group of teeth has a more buccal or lingual position and can be classified in anterior or posterior and bilateral or unilateral. Anterior crossbite is seen in Angle Class III skeletal malocclusion, while posterior crossbite correlates to a narrow maxilla. 12. Centric Occlusion and Centric Relation Centric occlusion is the occlusion of opposing teeth when the mandible is in centric relation to the maxilla. Centric occlusion is the first tooth contact and may or may not coincide with maximum intercuspation. It is also referred to as a person’s habitual bite position. Centric relation should not be confused with centric occlusion, which is the relationship

between the maxilla and mandible. 13. Vertical Dimension of Occlusion

This term is used in dentistry to indicate the superior-inferior relation- ship (height) of the maxilla and the mandible when the teeth are

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Resident Manual of Trauma to the Face, Head, and Neck