The longevity of direct and indirect posterior restorations is uncertain and may be affected by a number of dentist-, patient-, and material-related factors.

SELECTION CRITERIA

Information pertaining to how the studies were located and selected was very limited. The authors did state that they reviewed the "dental literature predominately from 1990" that reported on clinical studies with a minimum 2-year follow-up and at least an N of 10 at-risk restorations at the last recall.

KEY STUDY FACTOR

Although a number of important study factors were identified that could potentially impact posterior restoration survival, such as secondary caries, incorrect manipulation of the materials, or material fracture, no specific inclusion or exclusion criteria were identified that were applied across all studies reviewed.

MAIN OUTCOME MEASURE

This review concentrated on the longevity of restorations on posterior teeth subject to occlusal forces. The main outcome measure was survival of the restoration. Where applicable, measures of cause (secondary caries, marginal adaptation, fracture, wear, and so forth) were reported.

MAIN RESULTS

There were 42 amalgam studies, 51 direct composite, 5 direct composite with inserts, 7 compomer, 6 glass ionomer, 7 GI tunnel restorations, 6 GI ART restorations, 20 composite inlays and onlays, 36 laboratory-fabricated ceramic inlays and onlays, 20 CAD-CAM ceramic inlays and onlays, and 19 cast gold inlays and onlays. The values reported for annual failure rate were calculated for mean, median, and standard deviation for each material. Mean (SD) annual failure rates for posterior stress-bearing cavities were as follows: 3.0% (1.9%) for amalgam restorations, 2.2% (2.0%) for direct composites, 3.6% (4.2%) for direct composites with inserts, 1.1% (1.2%) for compomer restorations, 7.2% (5.6%) for regular glass ionomer restorations, 7.1% (2.8%) for tunnel glass ionomers, 6.0% (4.6%) for ART glass ionomers, 2.9% (2.6%) for composite inlays, 1.9% (1.8%) for ceramic restorations, 1.7% (1.6%) for CAD/CAM ceramic restorations, and 1.4%(1.4%) for cast gold inlays and onlays.

CONCLUSIONS

"Longevity of dental restorations is dependent upon many different factors, including materials-, patient- and dentist-related factors." "Principal reasons for failure were secondary caries, fracture, marginal deficiencies, wear, and postoperative sensitivity. We need to learn to distinguish between reasons that cause early failures and those that are responsible for restoration loss after several years of service."