Periodontal bone loss in English secondary school children. A longitudinal radiological study.

The prevalence and incidence of periodontal bone loss during a 3-year period was investigated in 373 English secondary school children aged initially 11--12 years. Bone loss was diagnosed from standard radiographs obtained at the baseline and third year examinations of a caries prophylactic clinical trial in which the children were participating. The interproximal spaces mesial and distal to the first permanent molar teeth were examined: 18.5% of subjects had evidence of bone loss at these sites at baseline and 44.0% at third year. In 60 subjects who had all second premolars and first and second permanent molars fully erupted and present at both examinations, the prevalence of bone loss was 36.7% at baseline and 68.3% at third year. Those children who had bone loss recorded at both the initial and final examinations had evidence of significantly more bone destruction at the conclusion of the study than those in whom bone loss was recorded only at the final examination (P less than 0.001).