Anatomy and development of the teeth
- J Tim Wright, DDS, MS
J Tim Wright, DDS, MS
- Professor of Pediatric Dentistry
- The University of North Carolina
The close relationship among oral, systemic, and psychologic health requires that oral health be evaluated thoroughly as part of health maintenance supervision. An understanding of the normal sequence and patterns of tooth eruption is the foundation for identifying and treating children with abnormal dental development and optimizing their oral health.
The normal anatomy and development of human dentition are reviewed here. Problems in dental development and syndromes associated with abnormal dental development are discussed separately. (See "Developmental defects of the teeth".)
Dental development proceeds from approximately the sixth week in utero through late adolescence. It involves the formation, eruption, and shedding of the 20 primary (deciduous or shedding) teeth, as well as the formation and eruption of the 32 permanent teeth. Throughout this prolonged span of development, the teeth are subject to both genetic and environmental influence. The timing, location, morphology, structure, and composition of teeth primarily are genetically controlled and are regulated by thousands of genes [1,2].
In addition to their role in speech and facial aesthetics, the teeth provide an efficient system of mastication with incising, tearing, and grinding capabilities. The unique composition and structure of teeth allow them to survive the forces and wear of mastication; alteration of the composition or structure of the teeth affects their durability, resistance to fracture, and retention in the oral cavity.
Each tooth has a visible crown that projects above the gingiva (gum), with one or more roots extending into the alveolar bone of the maxilla or mandible (figure 1). The crown and root meet at the neck of the tooth. The tooth forms a peg and socket joint with the alveolar bone and is held in place by the periodontal membrane that allows slight movement of the tooth.
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