Analysis of an administrative database of indirect restorations over 11 years

AIM: This paper describes the database used to assess the survival of indirect restorations and presents general data on survival of these restorations. METHODS: Data, based on the complete attendance and treatment history, over the 11 years from 1991 to 2001, of a statistically representative sample of 23,165 General Dental Services' (GDS) patients in England and Wales, all of whom received at least one indirect restoration during the observation period, have been analysed. The patients on the database received a total of 36,397 courses of treatment, and there were 52,481 indirect restorations placed. The method of analysis involved the estimation of the probability that the patient will eventually return, given an interval without attending, by analysing the observed patterns of re-attendance. This estimated probability of re-attendance was then used to modify the standard Kaplan-Meier procedure to produce realistic estimates of the hazard of re-intervention. RESULTS: Overall, 75% of indirect restorations remained without re-intervention after 5 years, and 61% after 10. Crowns outperformed other types of indirect restoration. Multi-surface metal inlays, by contrast, had a median interval to re-intervention of less than 8 years. CONCLUSIONS: The times to re-intervention for different types of indirect restoration have been successfully estimated and crowns shown to outperform veneers and inlays.