Asian Journal of Dental Sciences

Aims: To evaluate the effect of 15% papain enzyme on the shear bond strength of composite resin to dentin pretreated with 37% phosphoric acid or 15% ethylenediaminetetraacetic acid (EDTA).

Study Design: In vitro comparative experimental study.

Place and Duration of Study: Department of Conservative Dentistry and Endodontics, KVG Dental College and Hospital, Kurunjibagh, Sullia, India; study period: 6 months.

Methodology: Thirty-two extracted human maxillary premolars were embedded in acrylic resin. Occlusal enamel was removed to expose flat dentin surfaces, which were standardised with 600-grit silicon carbide paper. Specimens were allocated equally to four groups (n = 8): 37% phosphoric acid; 37% phosphoric acid plus 15% papain; 15% EDTA plus 15% papain; and 15% EDTA. Following surface treatment, adhesive and composite resin were applied. Shear bond strength was measured with a universal testing machine. Summary statistics were analysed using one-way analysis of variance and Tukey post hoc testing, with statistical significance set at P < .05.

Results: Mean shear bond strength was highest with phosphoric acid (16.55 +/- 0.72 MPa), followed by phosphoric acid plus papain (15.97 +/- 0.70 MPa), EDTA plus papain (15.31 +/- 1.86 MPa), and EDTA alone (13.22 +/- 2.46 MPa). Recalculation from the reported group sizes, means and standard deviations showed an overall difference (F(3,28) = 6.42, P = .002). Tukey testing identified differences between Groups I and IV (P = .002) and Groups II and IV (P = .011).

Conclusion: Papain used after phosphoric-acid etching maintained high dentin bond strength, whereas EDTA alone produced the lowest values. Papain may be a useful dentin-deproteinising adjunct, although larger studies evaluating long-term bond durability are required.