Objective: To investigate incipient alveolar bone loss and subgingival calculus on a subject-based level in Swedish 19-year-olds, with special reference to risk factors and risk indicators.
Material and methods: Subjects (n=686) with different socio-economic profiles enrolled at seven public dental clinics in suburban Stockholm answered a questionnaire on general health, tobacco habits, oral hygiene habits, and their parents' socio-economic background. The clinical and radiographic examination included registration of plaque, bleeding on probing (GBI), supra- and subgingival calculus, caries, and restorations. Incipient alveolar bone loss was recorded when the distance from the cemento-enamel junction to the alveolar crest was > or =2.0 mm.
Results: The prevalence of incipient alveolar bone loss was 5.1%; multivariate analysis disclosed the associated variables to be "subgingival calculus" (odds ratio (OR) 4.2) and "proximal restoration > or =1" (OR 2.1). The cumulative probability of exhibiting incipient alveolar bone loss was 19.6%. The prevalence of subgingival calculus was 14.3% and subgingival calculus was associated with "GBI > 25%" (OR 6.0), "supragingival calculus" (OR 4.6), and "father born abroad" (OR 2.8). The cumulative probability of exhibiting subgingival calculus was estimated to be 65.3%.
Conclusions: Adolescents with subgingival calculus as well as proximal restorations are at higher relative risk of exhibiting incipient alveolar bone loss than are those without subgingival calculus. In contrast to incipient alveolar bone loss, immigrant background was significantly associated with subgingival calculus among Swedish adolescents.