Stain removal effect of novel papain- and bromelain-containing gels applied to enamel

The aims of the study are to prepare novel stain removal gel-based formulations containing papain or bromelain and to investigate their stain removal effect when applied to enamel.

Experimental bromelain- and papain-based stain removal gels were prepared. Next, enamel/dentin tooth samples (6 × 6 mm², 4 mm in thickness) were obtained from bovine teeth, stained in coffee solution for 1 week, and measured with a digital spectrophotometer (Easyshade, Vita Zahnfabrik) for color assessment (baseline). The samples were then randomly allocated into four groups (n = 7), according to the stain removal agent applied: ContrastPM+ (Discus Dental, LLC), which is based on 20 wt.% carbamide peroxide (positive control); bromelain-based; papain-based; and no agent (negative control). The materials were applied once a week, three times per day, during 4 weeks, and following the directions of use from positive control. The samples were measured again with the Easyshade and using the CIEL ^* a ^* b ^* color system. The color change (ΔE ^*) results were obtained by subtracting the baseline values from the final color values obtained at each time point. The data were statistically analyzed using two-way repeated-measures analysis of variance and Student Newman Keuls’s test as a post hoc test (α = 5 %).

All stain removal agents produced greater color change than the negative control (p < .001), with the positive control demonstrating greater ΔE ^* values when compared to the experimental gels (p ≤ .004). The second application of all gels resulted in greater ΔE ^* values compared to the first application (p ≤ .025), although no color change was observed after the third application (p ≥ .051), regardless of the material evaluated.

The proposed gels containing proteolytic enzymes (bromelain or papain) of vegetal origin may hold significant clinical potential as active agents for the preparation of stain removal agents free of hydrogen/carbamide peroxide.