Cervical microleakage in composite restorations of primary teeth—in vitro study

Objective The purpose of this study is to evaluate in vitro the cervical microleakage of two bonding systems (Group 1: Scotchbond Multi-Purpose—3M; Group 2: Clearfil Mega Bond—Kuraray) in occluso-proximal composite restorations of primary molars. Methods Two occluso-proximal standard cavities preparations (vertical slots) were made in each one of the 11 primary molars. The cavities were filled using adhesive systems (one for each cavity) and hybrid composite (Filtek Z250—3M) by incremental technique. The first increment was inserted horizontally at the cervical wall and light-cured with 100 mW/cm2 intensity for 60 s (VIP™-Bisco). Other two increments were inserted diagonally on the buccal and lingual portion and each one light-cured with 200 mW/cm2 intensity for 60 s. The restorations were finished and polished, and then partially sealed and embedded in 0.5% methylene blue solution for 24 h. The specimens were sectioned mesio-distally and the dye penetration was evaluated (score from 0 to 3) under a stereomicroscope. Results The statistical analysis (Qui square and Mann–Whitney non-parametric test) revealed no statistical difference (p=0.193) between the two adhesive systems tested. Conclusions Both bonding systems provided small early cervical microleakage in occluso-proximal restorations of primary molars.