How long do routine dental restorations last? A systematic review

Objective To conduct a systematic review of the Literature on the longevity of routine dental restorations in permanent posterior teeth, and to identi fy and examine factors influencing its variability. Method Accepted guidelines were followed. An advisory group oversaw the pro ject. Simple Class I and Class II amalgam, composite resin, glass ionomer a nd cast gold restorations were covered. Comprehensive searching of electron ic databases, hand-searching, and location of 'grey' Literature, generated 124 research reports. Those considered relevant were assessed for validity and quality according to agreed criteria. The analysis was descriptive. Results Eight of 58 relevant research reports were categorised, according t o agreed criteria, as being of satisfactory validity and quality. They sugg ested that 50% of all restorations last 10 to 20 years, although both highe r and lower median survival, times were reported. The findings were support ed by the totality of studies reviewed. However, variability was substantia l. Restoration type, materials, the patient, the operator, the practice env ironment and type of care system appeared to influence longevity. Conclusions Many studies were imperfect in design. Those considered to be t he most appropriate for analysis were too limited to undertake a formal sta tistical exploration. Therefore there remains a need for definitive randomi sed controlled trials of restoration longevity, of sound design and adequat e power, employing standardised assessments and appropriate methods of anal ysis.