Microleakage of Class II Posterior Composite Restorations with and Without use of Liners - A Comparative Study

This study aims to compare the effect of liner on microleakage in Class II restorations at the occlusal and gingival levels when restored with a nanocomposite.

A total of 60 mandibular molars were selected and divided into three groups. Cavities in Group A were restored with posterior nanocomposite without liner, samples of Group B were restored with posterior nanocomposite with flowable composite liner and in Group C samples were restored with posterior nanocomposite with resin-modified glass ionomer cement (RMGIC) liner. Samples were stored at 37°C in 100% humidity for 14 days. Samples were subsequently immersed in 0.5% methylene blue dye and then placed under water for 15 mins. Teeth were sectioned mesiodistally with a diamond disc and examined under a stereomicroscope.

All the cavities exhibited dye penetration along the occlusal and gingival margins of the restored cavities. Group A showed maximum leakage compared to Groups B and C, which was statistically significant ( P = 0.001 and P < 0.0001). No significant difference in microleakage was observed between Groups B and C. Microleakage was more in gingival margins as compared to occlusal margins in all the groups.

Based on the results of the present study, it may be concluded that the placement of liner beneath nanocomposite restoration results in a significant reduction in microleakage.