Physiology of dentition

Primary Functions of Teeth

Prepare food for swallowing, facilitate digestion, articulate speech, and contribute to personal appearance/esthetics.

Functions Related to Tooth Form

Facilitate prehension, incision, and trituration of food.

Human Dentition

Considered omnivorous because the teeth, joints, and muscles have a form and alignment that permits mastication of both animal and vegetable foods.

Occlusion

The anatomic alignment of the teeth and their relationship to the rest of the masticatory system.

Occlusal Contact

When teeth of the lower jaw contact teeth of the upper jaw in any functional relationship, they are said to be in occlusion.

Malocclusion

A deviation in the relationship of the teeth and/or jaws.

Basal Bones

The maxillary and mandibular jaws considered in centric relation without the teeth.

Centric Occlusion

Contact of the teeth.

Gingival/Interproximal Papilla

Contact of each tooth with its neighbors helps protect the gingiva between them in the interproximal spaces.

Gingival Line

Follows the curvature of the tooth but is not necessarily at the same level as the cervical line or CEJ.

Cervical Line vs Gingival Line

The cervical line is a more stable anatomical demarcation, whereas the gingival line is variable and represents the gingival level on the tooth at a particular period of life.

Form of the Tooth

The anatomical shape of the tooth is closely related to the function the tooth performs.

Primary Factors Affecting Tooth Stability

Efficient mastication without damaging supporting structures; mastication that provides desired stimulation/exercise to the periodontium and cleans tooth surfaces; and the effects of jaws, face, and occlusal forces governing angulation, alignment, stability, and longevity of teeth in the arches.

Secondary Factors Affecting Tooth Stability

Cusp form, proportional measurement of crown and root, and root anchorage and angulations of teeth in the jaw.

Alignment and Contacts

The anatomic alignment of teeth and their relationship with the rest of the masticatory system.

Occlusal Contacts

Contact of mandibular teeth with maxillary teeth in any functional relation.

Interdental Papilla

A triangular fold of gingival tissue.

Interproximal Space

Space formed by the alveolar process as its base and proximal surfaces of adjacent teeth as its sides.

Col

A valley-like curvature/depression in the interdental gingiva directly apical to the proximal contact area.

Root Form

Includes the length and shape of the root and the angle at which the incisal or occlusal surface of the crown is positioned relative to the root bases.

Anterior Root Alignment

From the mesial view, the incisal ridge of an anterior tooth is centered over the root.

Root Flare

Flaring of roots in multirooted teeth contributes to stabilization.

Compensating Curvatures

Include compensating curves, Bonwill equilateral triangle, Curve of Wilson, Curve of Spee, and Curve of Monson.

Curve of Spee

An anteroposterior relationship/curve associated with Graf von Spee; described from the canine toward the buccal cusp of the first molar.

Mandibular Curve of Spee

The curvature of the mandibular arch is concave.

Maxillary Curve of Spee

The curvature of the maxillary arch is convex.

Bonwill Triangle

An equilateral triangle developed by Dr. Bonwill in 1899; measures from the condyle heads to the midpoint of the mandibular central incisors and measures approximately 4 inches or 10.16 cm.

Curve of Wilson

An imaginary mediolateral curve associated with cusp contacts; it is also a compensating curve.

Curve of Monson

Developed by Dr. Monson in 1920; combines the curvatures of Spee and Wilson, uses the glabella as the fixed point, and is based on a spherical theory of occlusion.