Microleakage of packable composite resins

This study evaluated the microleakage performance of a new generation of composites known as "packable" composites within a high C-factor preparation. Class V cavity preparations with occlusal margins in enamel and gingival margins in dentin were prepared on extracted human molar teeth. Prepared teeth were randomly distributed into four treatment groups (n=18) consisting of three "packable" composites-Alert, Solitaire, and SureFil-and a traditional anterior/ posterior small particle hybrid composite Z-100, Prime & Bond NT bonding agent was used with each composite. Samples were stored in tap water for 24 hours, thermocycled, stained with dye, sectioned into halves and scored for microleakage. All test groups showed a significant increase in both linear and penetrating dentinal microleakage when compared to enamel microleakage, Z-100 had significantly less dentinal marginal microleakage than SureFil, There was no significant difference in the enamel microleakage values between groups, However, the "packable" composites exhibited significantly higher percentages of enamel crazing adjacent to the cavity walls when compared to Z-100. The enamel crazing within the "packabbe" composite groups warrants further investigation to determine if this is a characteristic related to the composition of this class of composites, the mode of light curing used in this study or the result of the cavity/marginal design.