Efeito da contaminação salivar na resistência adesiva de resinas ortodônticas cromáticas

Abstract

Purpose: to assess the saliva contamination on shear bond strength about two chromatics adhesives (Ortho Lite and Transbond Plus Color Change) comparing with the conventional adhesive Transbond XT. Material and method: the sample composed of 120 bovine mandibular incisors was aleatory divided on 6 groups according to the adhesive used on, without (WC) and under contamination (UC). WC subgroups: etched with 37% phosphoric acid for 30 seconds, and a primer layer application; UC subgroups, which after the primer layer, the surfaces were contaminated with saliva, being reapplied a second primer layer. After 30 days of storage under ± 37ºC distilled water, the specimens were subjected to shear test, at 1mm/min cross-speed. Results: according the two ways ANOVA, is possible to verify that occur interaction between the contamination and adhesive factors. Thus the WC and UC subgroups presented some different behaviors, among the groups, the second (UC) showed a significant bond strength reduction. The G2 (WC) and G3 (UC) groups, within their subgroups, showed the higher bond strength score (mean = 26,49 MPa and 19,08 MPa, respectively) (Tukey Test p<0,05). The #1 score of ARI predominated, however, the ratio is not the same for all groups (Chi-Square Test p<0,05). Conclusion: we found a significative bond strength reduction over all adhesives tested on salivary contaminated environment. Nevertheless, all adhesives showed satisfactory mean values for orthodontic practice.