(den-tish'ŏn )

[L. dentitio, stem dentition-, teething, cutting teeth, dentition]

The type, number, and arrangement of teeth in the dental arch.

SEE: illus. ; teeth for illus.

diphyodont d.Two sets of teeth, the primary and the permanent, as in many mammals and humans.

heterodont d.A set of teeth of various shapes that may serve different functions (such as incisors, canines, and molars).

mixed d.A set of both primary and permanent teeth, as in children between 6 and 13 years of age. Also known as “transitional dentition.”

monophyodont d.A single set of teeth.

permanent d.The 32 permanent teeth, which begin to erupt at about age 6 in humans. These are completed by the 16th year with the exception of third molars, which appear between the 18th and 25th years. The incisors are followed by the bicuspids (premolars) and the canines; then the second molars are followed by the third molars. In some individuals the third molars, although present beneath the gingiva, do not erupt. The appearance of the first molars is highly variable, but in some instances they may be the first permanent teeth to appear.

SEE: permanent tooth .

polyphyodont d.Several successive sets of teeth developing during a lifetime.

primary d.The 20 primary or deciduous teeth in children. In general, the order of eruption is two lower central incisors, 6 to 8 months; two upper central incisors, 5 to 7 months; two lower lateral incisors, 8 to 11 months; two upper lateral incisors, 7 to 10 months; four canines (cuspids), lower and upper, 16 to 20 months; four first molars, lower and upper, 10 to 16 months; four second molars, upper and lower, 20 to 30 months.

SEE: deciduous tooth .