The Effect of Microleakage on Composite Resin Restorations Cured by Different Light Curing Units (LCU)

Objective: This study aims to compare the microleakage of Class V composite resin (CR) restorations; (i) cured using different LCU, (ii) restored by different CR and cured with different LCU, (iii) restored by different CR and cured with different LCU at the occusal and gingival margin. Materials and Methods: Sixty (60) permanent upper premolars were used. Two class V cavities (3 millimeter (mm) x 2 mm) with the occlusal and gingival margin ended 1 mm above and below cemento-enamel junction were prepared on the buccal and lingual surface of each tooth. The 120 cavities were divided randomly into four groups (n=30). Cavities in group one and three were restored with nanocomposite while cavities in group two and four were restored with microhybrid. Cavities in group one and two were cured using LED LCU while cavities in group three and four were cured using Halogen LCU. The samples were then immersed in 0.5% methylene blue dye for 24 hours and sectioned longitudinally. Microleakage at the occlusal and gingival margin was quantified in mm using stereomicroscope at 40x magnification. Data were analyzed using Mann-Whitney test and results with p < 0.05 were considered significant. Results: No significant differences in microleakage score were observed between use of different LCUs and different CRs. Both types of CRs cured using Halogen LCU showed statistically significant difference in microleakage score at the occlusal and gingival margin (p < 0.05). Conclusion: Microleakage was still present in both types of CRs cured using both LCUs. However, nanocomposite cured using LED LCU showed the least microleakage score.