Calcium hypochlorite as a dentin deproteinization agent: Microleakage, scanning electron microscopy and elemental analysis

This study investigated the influence of collagen removal with calcium hypochlorite on the surface morphology of acid-etched dentin and on the microleakage of composite restorations. In addition, the elemental composition (EC) of dentin after removal of the collagen fibrils was analyzed.

Forty third molars received two cavities and were divided into four groups according to dentin treatment: CTRL-no pre-treatment; Na10-10% NaOCl for 30 s; Ca10-10% CaOCl for 30 s, and Ca15-15% CaOCl for 30 s. The cavities were filled using an acetone-based adhesive system and a resin composite; they were then subjected to thermal cycling for 5,000 cycles, immersed in methylene blue for 4 h and sectioned into 1-mm thick slabs. Two examiners evaluated two slices per tooth using a stereomicroscope and assigned the degree of infiltration (scores 0-3). The data were analyzed using the Kruskal-Wallis (α = 0.05). Four teeth received surface treatment according to the groups and were submitted to SEM and EDS to carry at the EC.

There was no significant difference between the experimental groups (P = 0.533). CaOCl alters the morphology and surface composition of the dentin, resulting in an increase in the amount of calcium in the interface.

When used prior to an acetone-based adhesive system, CaOCl did not produce any differences in microleakage when compared to the CTRL group or to the Na10 group.