A clinical evaluation of posterior composite resin restorations: 8-year findings

Objectives: From a continuing investigation of the clinical performance of three different types of composite resin, the findings of the clinical evaluation at 8 years are presented. Methods: One operator placed 330 restorations in Class I and Class II preparations in the posterior teeth of 72 patients. Every patient received at least one restoration of each type of material: a microfilled composite: a small particle hybrid, a relatively coarse particle hybrid, and an amalgam control. Restorations were evaluated using clinical criteria. Results: Forty six patients attended the 8-year recall. Twenty-five of the 213 restorations (13.7% of the composites and 5.8% of the amalgams) originally placed in these 46 patients had previously failed or been lost from the study or were assessed as requiring replacement at the 8-year recall. Bulk fracture and secondary caries at the margin were the most common forms of failure in the composite restorations. Other failures or losses were associated with a non-margin defect in the composite, caries not associated with the restoration: pulpal considerations, extraction for orthodontics and reasons unknown. One-hundred and ninety-three restorations (including five that required replacement) were available for clinical evaluation at 8 years and these included 17 Class II restorations. Significantly fewer restorations placed with the coarse particle hybrid exhibited evidence of marginal deterioration. Conclusion: At 8 years, composite restorations in posterior teeth had failed at a rate two to three times that of amalgam restorations. The most common types of failure were bulk fracture and secondary caries at the margin. (C) 1998 Elsevier Science Ltd. All rights reserved.