Caries progression on approximal surfaces in contact with composite restorations
The study aimed to assess risk factors for caries progression on approximal surfaces in contact with newly placed Class II composite resin restorations.
This is a prospective, practice-based study. From 2001 to 2004, a total of 3286 Class II composite resin restorations were placed in 1609 patients aged 6–57 years by 26 dentists in the Public Dental Service in Norway. 91.7% of the restorations were placed due to primary caries. The restorations were followed for a mean of 4.6 years. At baseline and endpoint, all approximal surfaces in contact with the study restorations were evaluated by clinicians, using standardized clinical and radiographic criteria. A sub-sample of 333 approximal surfaces with caries confined to enamel at baseline and ≥4 years observation time were used in the present study.
Of those surfaces that initially had caries confined to enamel, 45.8% of the lesions progressed into dentin. Logistic regression analyses identified low age of the patient (OR 0.86; CI 0.76–0.97), high caries experience at baseline (OR 1.07; CI 1.00–1.14), surfaces in contact with restorations in premolars (OR 1.78; CI 1.08–2.95) and if the restoration in contact with the lesion had been replaced during the study period (OR 2.72; CI 1.01–7.31), as factors significantly related to caries progression on surfaces in contact with newly placed composite resin restorations. Variables related to the dentist, such as preparation technique, use of protection shield during preparation and whether the restorations were evaluated by the operator or another clinician, did not significantly affect the risk of caries on surfaces in contact with the study restorations.
Patient-related variables, such as age and caries experience, seem to be more important than dentist-related variables for caries progression on approximal surfaces in contact with Class II composite resin restorations.