A 6-year longitudinal study of caries in teenagers and the effect of "dropouts" on the findings.

摘要: Objectives: To investigate attrition of subjects in a longitudinal study caries. Design: A radiographic caries and caries-associated factors was carried out subjects, initially aged 14 years, followed-up for six years. Attrition occurred at the last stage study. Setting: nationwide survey living fishing, rural farming, urban communities Iceland. Sample Methods: sub-sample random sample comprising 150 investigated using bitewing radiographs structured questionnaire to determine caries-risk factors. Subjects were re-examined 16 years 20 same methods. Results: Mean increment from 14-16 3.0 lesions (1.5 lesions/subject/year) but reduced 2.6 (0.7 lesions/subject/ year) by 20y. The proportion found be caries-free 29%, 17% 10%, respectively. "Dropouts" this mostly after Analysis dropping showed that they least likely farming community most fishing community. Those attended their dentist less frequently, had higher consumption carbonated drinks prevalence incidence Conclusions with high-risk behaviours, or residents more drop Recognised advantages conducting studies may, therefore, lost.