Evaluation of the marginal integrity of a bioactive restorative material

This in vitro study evaluated the marginal microleakage of a bioactive restorative with other restorative materials in standard Class V preparations. Sixty previously extracted, noncarious human molars were randomly assigned to 3 experimental groups (n = 20): a bioactive composite resin, a universal hybrid composite resin, and a resin-modified glass ionomer restorative. Class V cavities were prepared on the facial or lingual surface of each tooth so that coronal margins were located in enamel and apical margins in cementum (dentin). After the cavity preparations were restored with the appropriate material, the specimens were artificially aged in water baths. The root apices were sealed with utility wax, the tooth surfaces were coated with nail varnish to within 1 mm of the restoration, and specimens were immersed in 1% methylene dye solution for 8 hours. The teeth were invested in clear polymer resin, sectioned longitudinally, and examined under a stereomicroscope to assess dye penetration. Nonparametric scores indicated that microleakage was significantly greater at the apical margins than the coronal margins for all groups (P > 0.0001). The specimens restored with the bioactive material exhibited greater microleakage at both the coronal and apical margins than did specimens restored with the composite resin or resin-modified glass ionomer material, although the differences were not statistically significant (P > 0.05). Based on the results of the present study, the type of restorative material did not appear to have a significant influence on microleakage. Rather, the marginal position (coronal versus apical) of the restoration was the determining factor in microleakage.