Marginal bone loss in the primary dentition

The present study was designed to determine the prevalence of bone loss in the primary dentition of children. Radiographs from children aged 7–9 were collected from 25 out of a total of 26 Public Dental Clinics in the County of Örebro, Sweden. These radiographs, representing 36.0%, 50.3% and 48.7% of all 7‐, 8‐ and 9‐year‐old children ( n = 8666) living in the districts of the participating clinics, constituted a primary sample. In addition, the 9‐year‐olds were subjected to a more comprehensive sampling procedure to obtain a more complete sample (sample of 9‐year‐olds), resulting in a group of 2017 children (71.9%). The radiographs were evaluated with respect to presence of marginal bone loss (CEJ‐MBL: distance between the cemento‐enamel junction and the marginal bone level >2 mm), proximal calculus and number of decayed and filled proximal surfaces (dfs p ) in the posterior areas of the primary dentition. In the primary sample, the prevalence of bone loss for 1 proximal surfaces of the primary dentition in the 7‐, 8‐ and 9‐year‐old children was 2.0%, 3.1% and 4.5%, respectively. The corresponding figures for proximal calculus were 2.5%, 3.1% and 4.2%. Mean number of dfs p amounted to 2.3, 2.5 and 3.0. The prevalences of bone loss and proximal calculus as well as the mean number of dfs p in the sample of 9‐year‐olds corresponded to the findings for the 9‐year‐old children in the primary sample. The analyses of the sample of 9‐year‐olds showed that most of the children with bone loss had 1 affected surface only. The largest CEJ‐MBL distance for each individual with bone loss ranged from 2.5 to 6.0 mm. Children with bone loss displayed calculus more often than children without bone loss. The children with bone loss also showed higher mean dfs p compared to children without bone loss.