Objectives: Determine the survival time of posterior composite restorations (PCR) performed on permanent teeth in National Dental Practice-Based Research Network (PBRN; www.NationalDentalPBRN.org) practices using electronic dental record (EDR) data, and quantify any differences by patient age, gender, tooth type and Network region.
Methods: Ninety-nine Network general dentistry practices that used Dentrix® or EagleSoft® EDR shared de-identified data of patients who received PCR on permanent teeth through October 31, 2015. We calculated survival time as the number of years of post-PCR observation or extraction of the tooth, whichever came first. We retrieved patient age, gender, and insurance, date of PCR, tooth type, and the date and type of subsequent restorative procedures on the same tooth or tooth extraction. The last dental visit was considered the censoring date. Univariate Kaplan Meier analysis was performed on categorical variables and multivariate analysis was done using a marginal Cox model for clustered data to account for correlation of multiple teeth within the same patient (p<0.05).
Results: 829,117 permanent teeth (203,212 patients) received PCR with 66% performed on molar teeth, and 34% on bicuspids. The observation period ranged from 0 days-25 years; median survival time was 4.58 years (95% confidence interval: 4.56, 4.62 years). The Kaplan Meier statistics demonstrated statistically significant differences in survival time by age. The Cox model detected significant differences by patient gender, age, tooth type, insurance, number of restored surfaces, and Network region.
Conclusions: The results indicated a shorter survival time than reported in a previous study with annual failure rate of 1.8% at 5 years. The inability to distinguish glass ionomer cement restorations from PCR because they have same procedure codes and treatment variations across practices may have affected the survival time. Future work include determining the annual failure rate and the factors contributing to the survival time of PCR.