Effect of cavosurface margin configuration of Class V cavity preparations on microleakage of composite resin restorations

The aim of this study was to compare the marginal leakage of hybrid and microfilled composite resin in Class V restorations with and without an enamel bevel.

Fifty-six cavities were prepared on the buccal and lingual surfaces of 28 extracted human molars using a round bur with the dimensions of 3 x 2 x 1.5 mm. The specimens were divided into two groups of 28 based on the cavosurface margin configuration (beveled and non- beveled). Each group was then divided into two subgroups (n=14) based on the type of composite resin (microfilled and hybrid) used for restoration. After completing restorative procedure, specimens were thermocycled and immersed in 0.5% basic fuchsine. Samples were embedded in polyester and then sectioned both mesiodistally and buccolingually. Dye penetration was observed with a stereomicroscope at 25 x magnification. Statistical nonparametric analysis Kruskal-Wallis and Mann-Whitney tests were performed to compare the data (a=0.05).

There was no statistically significant difference between the two types of composites and two types of enamel margins with respect to microleakage (P>%5). The degree of microleakage at the gingival margin located in dentin of each group was more than that of the enamel margin (P<%5).

An enamel bevel in a Class V cavity preparation had no effect on the reduction of marginal leakage using either hybrid or microfilled composite resin.