Incidence of caries lesions in approximal surfaces: a radiographic study of a general adult Danish population

The aim was to describe the incidence of caries lesions in a randomly selected adult population, and to identify risk factors related to the incidence of caries lesions in approximal surfaces. In 1997, 616 adults participated in a study including a radiographic survey. In 2003 these individuals were contacted again and offered a second radiographic survey; 473 consented and attended this examination. In approximal surfaces, presence/absence of caries lesions and presence and type of coronal fillings were recorded. The incidence of caries lesions in surfaces with no caries lesions in 1997 was studied. Potential risk factors included information at three levels: (1) person, (2) tooth, and (3) surface. The analysis was carried out by multilevel logistic regression. For the analyses 23,701 approximal surfaces were eligible. In 23,243 approximal surfaces no caries lesions were detected in 1997, 17,007 of these were surfaces without fillings, and 6,236 were filled surfaces. In unfilled surfaces several factors affected the risk for development of a caries lesion: young age, high number of fillings, number of teeth and status of the adjacent surface. In filled surfaces few factors affected the incidence of caries lesions: status of the adjacent surface, smoking and distal surfaces. Differences in risk factor patterns for the incidence of caries lesions were found for unfilled and filled surfaces. The study emphasizes the importance of assessing factors related to the incidence of caries lesions in adults. Further it underlines the need to analyse the fate of filled surfaces separately, because once a surface has received a filling it needs continuous attendance.