RESUMO
This study investigated the influence of a papain-based gel(Papacárie) for chemo-mechanical caries removal on bond strength todentin. Human molars were assigned to the following groups: Group 1:sound teeth were flattened to expose dentin; Group 2: after flattening ofsurfaces, the papain-based gel was applied on the sound dentin; Group3: overlying enamel from carious teeth was removed and mechanical excavationof dentin was conducted; Group 4: chemo-mechanical excavationof carious dentin was conducted using the papain-based gel. ThePrime&Bond NT or Clearfil SE Bond adhesive systems were used forrestorative procedures. A microtensile bond strength test was performed,and the modes of failure were determined under SEM. The data weresubmitted to two-way ANOVA and Tukeys test (p ≤ 0.05). No significantdifferences were observed between the sound dentin groups. Forboth excavation methods, Clearfil presented a significantly higher bondstrength than Prime&Bond NT. Also, for Clearfil, the mechanically excavatedsamples disclosed a significantly higher bond strength than thechemo-mechanically ones. For Prime&Bond NT, no significant differenceswere detected between the excavation methods. Predominance ofmixed failures for the sound substrate and of adhesive failures for thecarious dentin one was detected. The bond strength to carious dentinof the self-etching system was negatively affected by chemo-mechanicalexcavation using the papain-based gel.