AN ASSESSMENT OF APPROXIMAL BONE HEIGHT IN THE POSTERIOR SEGMENTS OF 15-16-YEAR-OLD CHILDREN USING BITEWING RADIOGRAPHS

The alveolar bone height in a total of 713 15-16-year-old children con sisting of 364 males and 349 females was assessed using posterior bite wing radiographs. The distance between the alveolar crest (AC) and ame lo-cemental junction (ACJ) on all molar and premolar teeth was determi ned from magnified images of the radiographs. Analyses of variance mod els were fitted in order to assess the dependence of the overall ACJ t o AC distance on the inter-subject variables of gender and social clas s and the intrasubject variables of site, missing adjacent tooth, cond ition of the approximal tooth surface, and for mesial surfaces, gingiv itis and pocket depth. The overall geometric mean for bone height for the whole population was 0.542 mm. The ACJ to AC distance for the vast majority of sites was below 2 mm. Site had a highly significant effec t on bone height (P<0.001): ACJ to AC distances were greater in the ma xilla compared to the mandible (P<0.001), greater for distal sites com pared to mesial (P<0.001) and significantly affected by tooth type (P< 0.001). Sites with missing adjacent teeth also had significantly incre ased distances (P<0.001). The condition of the approximal tooth surfac e and the presence of pocketing or gingivitis did not have a significa nt association with bone height. The geometric mean AC to ACJ distance , adjusted for subject, site and social class was 0.577 mm for males a nd 0.506 mm for females (P<0.001), but the main effect of social class was not significant.