Effect of bioactive and conventional liners on marginal sealing and dentin bond strength of Class V resin composite restorations: an in vitro study.

OBJECTIVE

The objective of this in vitro study was to evaluate the effects of different cavity liners on microleakage and microtensile bond strength (µTBS) between composite restorations and dentin.

METHODOLOGY: Seventy-five extracted human third molars were randomly allocated into five groups for microleakage evaluation, eight teeth were assigned to each group, whereas seven teeth per group were used for microtensile bond strength testing. These Class V cavities were created. Meanwhile, seven samples were utilized for µTBS testing. Group 1 (control): Filtek Z250, Group 2: Filtek Supreme Flowable Restorative, Group 3: Glass Liner, Group 4: ACTIVA BioACTIVE Restorative, Group 5: TheraBase Ca. The specimens were exposed to 10,000 thermocycles (5-55 °C) and 50,000 mechanical loading cycles (100 N). For microleakage testing, the specimens were then immersed in a 2% methylene blue solution for precisely 24 h in order to facilitate penetration, and then buccolingual sections were taken and examined with a stereomicroscope. Sections were taken from the teeth and tested for µTBS using a universal testing machine at a crosshead speed of 0.5 mm/min. The data were then analyzed.

RESULTS

Significant differences in microleakage scores were observed among the groups (p = 0.008). The control group demonstrated significantly lower microleakage than the flowable composite liner group, whereas no significant differences were observed among the remaining groups. µTBS values also differed significantly among the groups (p < 0.001). Group 3 (Glass Liner) demonstrated the highest bond strength values, whereas Group 5 (TheraBase Ca) demonstrated the lowest values. Overall, liner type did not appear to substantially influence composite microleakage, whereas dentin bond strength varied among the tested liner materials.

CONCLUSION

Within the limitations of this in vitro study, liner type did not appear to substantially influence composite microleakage, whereas dentin bond strength varied among the tested liner materials. Further studies are required to confirm these findings.