Ten-year clinical performance of PCR's placed by dental students

Objectives: To investigate the longevity and reasons for failure of posterior composite restorations (PCR) placed by students at the Nijmegen Dental School. Methods: For this retrospective study PCR's placed by 2nd to 5th year dental students in the period from 1990 until 2004 were evaluated from randomly selected patients' records of the Dental School. PCR's were placed under supervision of a dentist-staff member according to a fixed protocol. All patients attended recall sessions every 6 months during the evaluation period. From each record the survival and reason for failure of each PCR was recorded. Life tables were used to establish mean annual survival and a Cox regression was applied to identify the effect of different variables on the survival rate. Results: In total 1287 PCR's placed in 481 patients (48% male / 52% female, age 9-77) were evaluated. From the Life Table an overall cumulative survival rate of 64% after 10 years was calculated, resulting in a mean annual failure rate of 4,4%. Main reasons for failure were caries (22%) and fracture of the restoration and/or tooth (15%). A significant higher failure rate was recorded for larger restorations (p<0.01) and for older patients (p<0.01). Conclusion: Dental students can place posterior composite restorations with acceptable annual failure rate.