Longevity of repaired restorations: a practice based study

Abstract

The aim was to evaluate retrospectively the influence on restoration longevity of a repair and to evaluate longevity of repaired restorations.

Materials and methods: In a practice, 1202 amalgam and 747 composite resin restorations were placed. 407 restorations failed (amalgam 293, composite 114), 246 restorations were repaired with composite resin using an etch-and-rinse technique. Of repaired restorations reason for failure and number of surfaces of original restoration, repair date, and date of patients' last visit were recorded. Whenever a new treatment was necessary, this was considered failure. Data were analysed by Kaplan-Meier statistics and log-rank tests (p<0.05). A multi-variate Cox-regression analysis was conducted on results for variables number of surfaces, repair reason, and repaired material.

Results: 133 amalgam restorations (57% due to fracture) and 113 composite restorations (62% due to caries) were repaired. 151 of 246 repaired restorations (61%) were still in service without further intervention after 4.8 years. The annual failure rates for repaired amalgam and composite restorations was 9.3% and 5.7% after 4 years (log-rank, p=0.001). Restorations that were repaired due to fracture had a lower survival than restorations that were repaired due to caries (log-rank, p=0.006). The Cox-regression showed influence of the gender but no significant influence of material or reason for repair, indicating that the findings are a consequence of joint negative influences of investigated variables.

Conclusion: The present study shows that repairs can enhance the longevity of dental restorations considerably. Moreover, repairs on restorations failing due to caries have a better prognosis compared to repairs on restorations failing due to fracture.