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A longitudinal study of the growth and development of the dental arch width from childhood to adolescence in Japanese.

The purpose of this study was to evaluate the longitudinal changes in arch width from childhood to adolescence. The subjects were 28 persons (13 males and 15 females) with untreated normal occlusion. Dental casts were taken at bimonthly intervals from childhood to adolescence. These materials were measured; the changes in the dental arch were compared on the basis of the status of the tooth emergence of certain permanent teeth and also on the chronological age from 3 years to 20 years of age. In the maxilla and mandibula, the width between the deciduous canines, the width between the first deciduous molars, and the width between the second deciduous molars were nearly stable or slightly increased until 6 years of age. After that, all of the deciduous tooth widths gradually increased, especially in the width between the deciduous canine at the emergence of the permanent incisors. The width between the canines decreased until 13 years of age in the maxilla and until 15 years of age in the mandibula. After that, the width between the canines were nearly stable. Until 1 year after emergence, the width between the canines decreased, in particular during the transition to the canines, based on dental age observation. The maxillary first premolar width decreased until 6 months after emergence, based on dental age observation. Thereafter, the width between the maxillary first premolars showed no clear change. The width between the mandibular first premolars, the width between the maxillary second premolars, and the width between the mandibular second premolars increased until about 2-3 years after emergence, but they showed no clear changes thereafter. The width between the maxillary first molars gradually increased until 15 years of age; there was no clear change thereafter. The width between the mandibular first molars was nearly stable throughout the observation period. The width between the maxillary second molars decreased until 2 years after emergence; no clear change was observed thereafter. The width between the mandibular second molars was unstable until after about 2-3 years after emergence and then became nearly stable.