Longevity and reasons for failure of sandwich and total-etch posterior composite resin restorations

To investigate longevity and reasons for failure of Class II posterior composite restorations (PCRs) placed with or without a lining of glass-ionomer cement.

Four hundred fifty-eight Class II PCR placed in 248 patients (110 male, 138 female, age 18 to 80) by two dentists in a general practice between 1988 and 1997 were retrospectively examined from the patient files. The restorations were placed either with a total-etch technique or with a resin-modified glass-ionomer lining placed on the dentin. Items recorded were date of placement, date of last check-up visit, tooth number, and restored surfaces. Date of replacement and reason for failure of the PCR was recorded. A restoration was clinically acceptable when still in function and acceptable at the last check-up visit. Additionally, the caries risk for each patient was estimated by the treating clinician. Life tables and Kaplan-Meier curves were used to express survival rates. A Cox regression was applied to assess the influence of variables on survival.

Three hundred seventy-six total-etch PCRs and 82 PCRs with a lining were investigated. After 9 years, survival percentages of 88.1% for total-etch restorations and 70.5% for restorations with a resin-modified glass-ionomer lining were found. The most important reasons for failure were fracture and caries. Predominantly, failures started occurring after 3 to 4 years of clinical service. Results of the Cox regression show that the presence of a lining and high risk for caries significantly increased the failure rate of the restorations.

PCRs placed with a resin-modified glass-ionomer lining clinically showed more frequent fractures than PCRs placed with a total-etch technique.