Influence of root canal fillings on longevity of direct and indirect restorations placed within the General Dental Services in England and Wales

Aim To consider the survival of restorations in root filled and non-root filled teeth. Methods A data set was established consisting of patients, 18 years or older. For each patient on the database with a tooth restored with a direct or indirect restoration with or without a root filling, the subsequent history of intervention on that tooth was consulted, and the next date of intervention, if any could be found in the data set, was obtained. Thus a data set was created of restored teeth and whether they have also received root fillings, with the dates of restoration and root filling placement and the dates, if any, of re-intervention. Modified Kaplan-Meier statistical analysis was used to quantify the distribution of time to intervention. Results Data for over 80,000 different adult patients were analysed, of whom 46% were male and 54% female. A total of 538,967 restoration placements were obtained from the data over a period of 11 years, of which 30,073 were root fillings. Conclusions Examination of the survival of restorations in teeth with and without root canal fillings indicated that those with root canal fillings have shorter intervals before re-intervention than teeth without root fillings. Restorations on root canal treated anterior teeth with post and cores had the lowest survival time.