Effect of 10% papain gel on enamel deproteinization before bonding procedure

OBJECTIVE: To test the null hypothesis that enamel deproteinization with 10% papain gel does not increase the shear bond strength of orthodontic brackets bonded with resin-modified glass ionomer cement (RMGIC). MATERIALS AND METHODS: One hundred and twenty bovine incisors were used and divided into eight groups: 1) Transbond XT according to the manufacturer's recommendations, 2) Transbond XT deproteinized with 10% papain gel, 3) RMGIC without enamel deproteinization and without etching, 4) RMGIC without enamel etching and with deproteinization with 10% papain gel, 5) RMGIC deproteinized with 10% papain gel and etched with polyacrylic acid, 6) RMGIC deproteinized with 10% papain gel and etched with phosphoric acid, 7) RMGIC deproteinized with 2.5% sodium hypochlorite, and 8) RMGIC etched with polyacrylic acid. After bonding, the mechanical tests were performed in a Universal mechanical test machine. The values obtained were submitted to an analysis of variance and afterward to the Tukey test (P < .05). RESULTS: It was demonstrated that group 2 presented the highest shear bond strength value, and this differed statistically from the others; group 3 presented the lowest value and showed no differences from groups 4, 5, 7, and 8. Regarding the Adhesive Remnant Index, groups 2 and 6 presented the best results and groups 3 and 8 the worst. It could be concluded that enamel deproteinization with 10% papain gel increases the shear bond strength, irrespective of the etching agent. CONCLUSIONS: The hypothesis is rejected. Papain gel was shown to be a new ally in the orthodontic clinic.