The aims of this study were to (1) quantify the prevalence of reason(s) for replacing existing restorations in DPBRN practices; (2) quantify the percentages and types of restorative materials of failed restorations that are being replaced in DPBRN practices; (3) quantify the percentages and types of restorative materials used to replace or repair failed restorations in DPBRN practices; and (4) test the hypothesis that DPBRN practitioner-investigators who reported in a previous study that they treat enamel lesions operatively are more likely in actual patients as in this study to replace entire restorations rather than do repairs and are more likely to report the clinical diagnosis of secondary caries as a reason for replacement.