Criteria for restoration replacement and restoration life-span estimates in an educational environment

The present survey assessed the subjective estimates of restoration longevity, the relative importance of the reasons to replace a restoration and the proportion of restorative treatment perceived to be carried out to replace previous restorations in a clinical setting where caries experience has been reported to be high. Three hundred and eight-four final-year dental students in Mexico City (64% female, mean age 23.2 years) made subjective longevity estimates (minimum acceptable, 'average' and ideal) for small and large amalgam restorations and cast restorations. Students attributed greater responsibility for restoration failure to patient-related factors than to dentist-related factors. The most important reasons given for the replacement of restorations were the presence of an active carious lesion and the presence of a lesion. The next most important reasons were the presence of fractured restorations, proximal overhangs or proximal marginal defects, and marginal defects. No marked differences could be detected in the restoration longevity appraisals compared either with other subjective estimations or to actual longevity figures, nor in the relative ranking of reasons to replace restorations between the estimates done by participants in this study and reports originating in low-caries settings.