ALVEOLAR BONE HEIGHT OF PRIMARY AND FIRST PERMANENT MOLARS IN HEALTHY7 TO 9-YEAR-OLD CHILDREN

The purpose of the study was to establish baseline values of the alveo lar bone height of the primary molars and first permanent molars in sa mple of healthy U.S. seven-to nine-year-old children. Direct measureme nts of the distance from the cementoenamel junction (CEJ) to the alveo lar crest (AC) on 223 pairs of bitewing radiographs from 223 subjects were made using a digimatic caliper under standardized conditions. The distance from the CEJ to the AC had medians from 0.58mm to 1.39mm (ra nge 0.0 to 4.44mm) for the primary molars and from 0.00mm to 0.64mm (r ange -1.35 to 2.15mm) for the mesial aspect of the permanent molars. T here were no statistically significant differences in the distance fro m CEJ to AC between teeth on the right and left sides of the mouth. Th e distances from CEJ to AC were always greater in the maxilla than in the mandible for similar primary molar sites, but only true for the me sial aspect of the permanent first molar at age nine. As a tooth is po sitioned more anteriorly in the mouth, the distance from CEJ to AC was greater. On the whole, males had greater distances than females and e ight-year-olds had larger distances than seven-or nine-year-olds. Diff erences were observed in the measured distances for the different age and sex-groups and may be attributable to variations in eruption and e xfoliation patterns. The distance was significantly greater in areas o f interproximal restorations and open contacts, and there was a tenden cy for the distances to be greater in areas of interproximal caries.