In vitro evaluation of an experimental copaiba oil-resin gel associated with 35% hydrogen peroxide bleaching on...

Teeth whitening is a procedure that, despite being less invasive and more affordable, can cause sensitivity and damage to the enamel. This study evaluated an experimental copaiba oil-resin gel associated with 35% hydrogen peroxide (HP 35%) teeth whitening. The biocompatibility of the experimental gel and the physicochemical, morphological, and mechanical properties of bovine enamel were assessed. Bovine incisor specimens (N = 30) were divided into 3 groups (n = 10): GC-whitening with HP 35%; GKF2%-potassium nitrate 5% and sodium fluoride 2% gel + whitening with HP 35%; GCO-experimental copaiba oil-resin gel + whitening with HP 35%. The viability of human gingival fibroblasts was analyzed using the MTT test. The color change (∆E00), mineral components by energy dispersive spectroscopy (EDS), enamel morphology by scanning electron microscopy (SEM), surface roughness (Ra) by 3D optical profilometry, and microhardness Knoop (KHN) were analyzed. The cells treated with the copaiba gel showed no signs of cytotoxicity. All groups showed color change. GCO presented smoother and more homogeneous surfaces. No significant loss of calcium or phosphorus was found. There was a statistical difference between groups in Ra values. Only GC and GKF2% showed a statistically significant increase in Ra. All groups exhibited a reduction in KHN (p < 0.05). A statistical difference in KHN was observed between groups. The color difference (CIEDE200, ΔE00), KHN values, Ra, and EDS were analyzed using one-way ANOVA and Tukey's test (p < 0.05). The copaiba gel showed no cytotoxicity, did not interfere with whitening or mineral loss, reduced morphological alterations, and did not affect KHN when compared to the other groups. The results suggest that the copaiba gel could improve patient acceptance and adherence to whitening treatments by reducing sensitivity and enamel damage.