Risk factors for secondary caries in direct composite restorations in primary teeth.

Background Secondary caries or caries adjacent to restorations is the most frequent reason for replacement of dental restorations. Though, limited data is available on variables influencing the development of secondary caries in primary teeth. Aim To investigate risk factors for the development of secondary caries adjacent to direct composite restorations in primary teeth. Design For this retrospective study, data of 2417 composite restorations, which were placed due to primary carious lesions, were considered. A total of 212 restorations failed due to secondary caries within a maximum observation period of 8 years. A control group was randomly selected. Mann-Whitney U-test, binomial logistic regression with backward elimination and Cox regression with frailty model were performed ( P < 0.05). Results The overall caries experience amounted to 6.3 dmft and 13.3 dmfs. 72.5% of restorations failed within the first 2 years. Older children and children from families with a higher socio-economic status showed a lower risk for secondary caries. Further, the dentist and the adhesive had a significant influence on the longevity. Posterior restorations had a higher risk to fail in comparison with anterior restorations. Conclusions Within the limitation of this study, it is concluded that the development of secondary caries is influenced by several factors. Nevertheless, the secondary caries rate was found to be relatively low in this high-risk population. [ABSTRACT FROM AUTHOR]