The survival of Class V restorations in general dental practice. Part 2, early failure

OBJECTIVE To evaluate Class V restorations placed by UK general practitioners comparing those failing or surviving after two years, and to identify factors associated with early failure. DESIGN Prospective longitudinal cohort multi-centre study. Setting UK general dental practices. MATERIALS & METHODS Ten dentists each placed 100 Class V restorations and recorded selected clinical information at placement and recall visits. Univariate associations were assessed between recorded clinical factors and whether restorations had failed or not at two years. Multi-variable binary logistic regression was also undertaken to identify which combination of factors had a significant effect on the probability of early failure. RESULTS At two years, 156 of 989 restorations had failed (15.8%), with 40 (4%) lost to follow-up. Univariate analysis showed a significant association between restoration failure and increasing patient age, payment method, the treating practitioner, non-carious cavities, cavities involving enamel and dentine, cavity preparation and restoration material. Multi-variable analysis indicated a higher probability of early failure associated with the practitioner, older patients, glass ionomer and flowable composite, bur-preparation and moisture contamination. CONCLUSIONS Among these practitioners, both analytic methods identified significant associations between early failure of Class V restorations and the practitioner, cavity preparation method, restoration material and patient's age.