Efeitos dos produtos OTC nas propriedades mecânicas do esmalte dentário em dentes submetidos ao tratamento ortodôntico: rugosidade superficial e resistência adesiva

Abstract

Over-the-counter (OTC) whitening products are low-cost, easily accessible and generally used without the supervision of dental surgeons. For aesthetic purposes, patients undergoing orthodontic treatment may choose to use them. This in vitro study evaluated the impact of overthe-counter products containing hydrogen peroxide on the mechanical properties (surface roughness and shear strength) of tooth enamel. For this purpose, 80 bovine teeth were selected to undergo a staining protocol and initial surface roughness assessment. Orthodontic brackets were then bonded to the center of the clinical crown of each sample and the teeth were subjected to whitening protocols. The samples were allocated into five groups (n=16): Conventional office bleaching with 35% Hydrogen Peroxide (HP) (HP35 Group) - positive control; Toothpaste with 2% HP (DHP Group); Mouthwash with 2.5% HP (MouHP Group); Paint with 6% HP (PON Group); Conventional toothpaste without HP (DSHP Group) - negative control. After receiving the whitening protocol, the samples were submitted to the shear strength test to remove the orthodontic bracket. The remaining resin was then removed from the sample surfaces using multi-blade drills, and the final roughness was evaluated under the center of the sample. The statistical evaluation detected no significant difference between the experimental groups for shear evaluation (p = 0.14). With regard to surface roughness, the statistical test detected a significant difference between the means of the groups (p = 0.007). When comparing the results obtained by Tukey's post hoc test, a significant difference was only found between the DSHP and HP35 groups (p = 0.008). The greatest change in surface roughness was in the group that used peroxide-free dentifrice. The current in vitro study suggests that the OTC products evaluated had no impact on the adhesive strength of orthodontic brackets to teeth or on changes in enamel roughness.