The development of an excellent occlusion

Abstract

The development of an excellent occlusion has been discussed. At the age of 7 years there were a midline deviation of 1.2 mm. and an end-to-end molar relationship which corrected themselves. At 10 years there was no interdental spacing distal to the deciduous maxillary canines. The permanent canines and the first and the second premolars were 1.8 mm. larger than the corresponding deciduous teeth. In the mandibular arch the size of the posterior deciduous teeth was similar to that of their corresponding permanent teeth. The maxillary permanent anterior teeth were 5.9 mm. larger than the corresponding deciduous teeth combined with the interdental spacing. In the mandibular arch the discrepancy was 5.3 mm. Several factors contributed to the good alignment of the teeth: (1) Caries on deciduous teeth did not affect interproximal surfaces. (2) There were small permanent posterior teeth and average anterior teeth within an average arch width. (3) The anterior teeth tipped labially from 6 to 9 years of age. The maxillary incisors changed 12 degrees, and the mandibular incisors changed 19 degrees. These changes, in turn, increased the space available for the canines and premolars. (4) The canines, the first and second premolars, and the second molars emerged simultaneously.