Clinical results and new developments of direct posterior restorations

Purpose: To (1) review the literature and analyze the longevity and reasons for failure of direct resin-based composite (RBC), amalgam, and glass-iono mer cement (GIC) restorations in stress-bearing posterior cavities and (2) to assess new material developments and treatment techniques to restore the se cavities. Materials and Methods: This work reviewed the dental literatur e predominately of the last decade for longitudinal, controlled clinical st udies and retrospective cross-sectional studies. Only studies investigating the clinical performance of restorations in permanent teeth were included. Annual failure rates of direct resin-based composite, amalgam, and GIC res torations were determined and failure reasons were discussed. Results: Annu al failure rates in posterior stress-bearing cavities were determined to be : 0-9% for direct RBC restorations, 0-7% for amalgam restorations, and 1.9- 14.4% for GIC restorations. The median annual failure rate of longitudinal studies for amalgam was calculated with 1.1%, for RBCs 2.1% and for GICs 7. 7%. GIC is significantly worse compared with amalgam and RBC. Main reasons for failure were secondary caries, marginal deficiencies, fracture, and wea r. Longitudinal studies showed a strong trend towards a higher longevity co mpared with cross-sectional investigations.