Whitening Dentifrices Effect on Enamel with Orthodontic Braces after Simulated Brushing

Abstract

Objective This study aimed to evaluate in vitro the effects of whitening dentifrices on enamel color, the shear bond strength of orthodontic brackets and adhesive remnant index (ARI). Materials and Methods Eighty bovine teeth with brackets were randomly divided into four groups (n = 20): control group (GC)–water, test group 1 (GT1)–Colgate Total 12, test group 2 (GT2)–Curaprox Black Is White, and group test 3 (GT3)–Luminous White. All groups were submitted to brushing, simulating 12 months. The specimens were exposed to spectrophotometer color evaluation and to a shear strength test in a universal test machine using a 300 kN load with a crosshead speed of 0.5 mm/min. The ARI was evaluated with a stereoscopic magnifying glass. Statistical Analysis Nonparametric Kruskal–Wallis and Dunn’s tests were used for the color analysis, and Friedman and Nemenyi tests were used to compare the times in the variable. To compare the shear force between the groups, the data were evaluated by one-way analysis of variance and Tukey’s test, and ARI was analyzed using Fisher’s exact test, always with a significance level of 5%. Results In the color analysis, GT3 presented the greatest progression in whitening effect. GT1 had greater shear strength than GT3 did (p ≤ 0.05). For ARI, the score 1 was predominant in the GC and GT1. The GT2 and GT3 groups had scores of 3. Conclusion The whitening dentifrices promoted significant color change over the 12-month brushing time and may have interfered in the resistance to shear bond strength and ARI.

Effect of Actilux - Activated Whitening Toothpaste and Marine Salts on Color Change and Microhardness of Bovine Enamel

“…This slight whitening effect may be related to the presence of hydrated silica which has greater ability to remove stains from enamel surface compared with other abrasives (4) . This result is consistent with a recent study reported that the toothpastes containing mechanical abrasive were effective in modifying the color of bovine enamel (23) . However, these results were in disagreement with another study that demonstrated that the traditional abrasive toothpaste was not able to improve the tooth color (13) .…”

Influence of topical fluoride on shear bond strength of orthodontic brackets and enamel white spot lesions formation

“…They were flattened by means of a metallographic polishing machine PL VO60 (Biopdi, São Carlos, SP, Brazil) to standardize the surfaces. The sample calculation was performed based on the effect sizes found in the literature 14,15 and ISO/TS 11405 16 recommendations for this study design. The sample size of 60 teeth, 20 in each group, provided 80% test power (β=0.20) to detect large effects (f=0.41) for shear bond strength and w=0.48 for ARI, with a significance level of 5% (α=0.05).…”

“…The vestibular surface of each test specimen was polished with silicon carbide water paper abrasive discs used consecutively, grit size of 180, 400 and 600 (3M do Brasil Ltda., Sumaré, SP, Brazil), in order to expose the same enamel area for bracket bond 3,[14][15][16] . The flattest portion of the vestibular surface of each crown was maintained as parallel as possible, without exposing the dentin, fixed in orthophthalic resin (Equifibras, Salvador, BA, Brazil), polishing and placed in an ultrasonic bath L-200 (Schuster TM Ltda) for 10 minutes to remove possible polishing residues.…”

“…Roth standard metal orthodontic bracket, slot 0.022" (Morelli Roth Max, Sorocaba, São Paulo, Brazil) for maxillary central incisors, was positioned on the tooth surface and excess of adhesive was removed from around the bracket base. The surfaces were light cured at a distance of 5 mm for 10 seconds on each bracket side, with light intensity of ˃500 mW/cm 2 (Dabi Atlante TM , Ribeirão Preto, Brazil), according to the manufacturer's instructions (3M TM , Minessota, USA) 14 .…”

“…The shear bond strength test was performed in a universal test machine EMIC (model DL 2000, São José dos Pinhais, Paraná, Brazil), using an adapter to position the test specimens, with the parallel downward direction to the surface at the base of the brackets. The speed of 0.5 mm/min was maintained until rupture occurred between the bracket and test specimen, with force recorded in Newtons (N) and converted into MegaPascal (MPa), according to the area of the bracket 14,15 .…”