Análise do perfil de liberação do princípio ativo peróxido de hidrogênio por diferentes géis clareadores dentais / Analysis of the release profile of the active ingredient hydrogen peroxide by different tooth whitening gels

O objetivo desse estudo foi analisar o perfil de liberação do princípio ativo peróxido de hidrogênio por diferentes géis clareadores no decorrer do período de aplicação. Para tal diferentes géis clareadores à base de peróxido de hidrogênio para uso na técnica em consultório foram levados à câmara doadora de uma célula de difusão vertical (célula Franz). Foi empregado como meio de difusão uma membrana de éster de celulose com porosidade de 100-500 Daltons. A câmara receptora foi preenchida com água ultrapura. Os seguintes géis foram testados: Whiteness HP (FGM), Whiteness HP Blue (FGM), Whiteness HP Automix (FGM), Potenza Bianco (PHS do Brasil), Opalescence Boost (Ultradent), e Pola Office Plus (SDI); solução de peróxido 35% controle. O peróxido de hidrogênio liberado pelo gel se difundiu através da membrana e se misturou com a água na câmara receptora. Uma amostra de 40µl foi coletada da câmara receptora a cada 5 min, durante 45 minutos e foi reposto o mesmo volume de 40 µl em água ultrapura. A concentração de peróxido na amostra (mg/ml) foi determinada em triplicata a cada momento, utilizando um espectrofotômetro leitor de microplacas e reagente enzimático. A normalidade e homoscedasticidade dos dados foram avaliadas pelos testes de Shapiro-Wilk e Levene. Os dados de quantidade acumulada de peróxido foram submetidos ao teste de análise de variância ANOVA a 2 fatores (tipo de gel x tempo) e teste de Tukey. Para todas as análises foi adotado um nível de significância de 5%. Diferenças significativas foram observadas para os fatores agente clareador (p=0,0001) e tempo (p=0,0001), assim como para a interação entre eles (p=0,0001). Os resultados do teste de Tukey para o fator agente clareador quanto à quantidade cumulativa de peróxido foram: WHPB-14,04(6,60)a, WHP19,51(8,61)b, WHPA-23,20(10,48)c, POP-26,53(11,13)d, PB-28,29(10,99)de, OPB31,03(11,81)e, Controle 79,12(32,27)f. Para o fator tempo, em minutos, os resultados foram: 5 9,64(6,70)a, 10-17,42(11,60)b, 15-24,03(16,86)c, 20-29,50(20,44)d, 25-33,93(23,00)e, 30-38,41(25,83)f, 35-41,52(27,32)fg, 40-44,11(28,47)gh, 45- 46,50(29,72)h. Os resultados do teste ANOVA de medidas repetidas mostraram diferenças significativas (p=0,00) em relação a concentração inicial e final de peróxido para os fatores agente clareador, momento de leitura e para a interação entre eles. Agentes clareadores com maior concentração inicial de peróxido de hidrogênio apresentaram maior liberação cumulativa do ingrediente ativo; a liberação de peróxido de hidrogênio de diferentes géis clareadores ocorre de maneira gradual em relação ao tempo de aplicação, porém essa liberação não ocorre de maneira constante.(AU)

The aim of this study was to analyze the release profile of the active ingredient hydrogen peroxide by different bleaching gels over the course of the application period. For this purpose, different bleaching gels based on hydrogen peroxide for use in the in-office technique were taken to the donor chamber of a vertical diffusion cell (Franz cell). A cellulose ester membrane with a porosity of 100-500 Daltons was used as diffusion medium. The receiving chamber was filled with ultrapure water. The following gels were tested: Whiteness HP (FGM), Whiteness HP Blue (FGM), Whiteness HP Automix (FGM), Potenza Bianco (PHS do Brasil), Opalescence Boost (Ultradent), and Pola Office Plus (SDI); 35% peroxide control solution. The hydrogen peroxide released by the gel diffused through the membrane and mixed with the water in the receiving chamber. A 40µl sample was collected from the receiving chamber every 5 min for 45 minutes and the same volume of 40 µl was replaced in ultrapure water. The peroxide concentration in the sample (mg/ml) was determined in triplicate at each time point, using a microplate reader spectrophotometer and enzymatic reagent. Data normality and homoscedasticity were evaluated using the Shapiro-Wilk and Levene tests. Accumulated amount of peroxide data was submitted to 2-way ANOVA test of variance (type of gel x time) and Tukey's test. For all analyses, a significance level of 5% was adopted. Significant differences were observed for the factors bleaching agent (p=0.0001) and time (p=0.0001), as well as for the interaction between them (p=0.0001). The results of the Tukey test for the bleaching agent factor regarding the cumulative amount of peroxide were: WHPB-14.04(6.60)a, WHP-19.51(8.61)b, WHPA-23.20(10 ,48)c, POP-26.53(11.13)d, PB 28.29(10.99)de, OPB-31.03(11.81)e, Control-79.12(32.27) )f. For the time factor, in minutes, the results were: 5-9.64(6.70)a, 10-17.42(11.60)b, 15-24.03(16.86)c, 20- 29.50(20.44)d, 25-33.93(23.00)e, 30- 38.41(25.83)f, 35-41.52(27.32)fg, 40-44, 11(28.47)gh, 45-46.50(29.72)h. The results of the repeated measures ANOVA test showed significant differences (p=0.00) in relation to the initial and final peroxide concentration for the factors bleaching agent, reading time and the interaction between them. Bleaching agents with a higher initial concentration of hydrogen peroxide showed a greater cumulative release of the active ingredient; The release of hydrogen peroxide from different whitening gels occurs gradually in relation to the application time, but this release does not occur constantly. (AU)

Efficacy of Bracket Adhesive Remnant Removal by a Fluorescence-Aided Identification Technique with a UV Light Handpiece: In Vitro Study.

Objective: This study aims to analyze the fluorescence-aided identification technique efficacy on adhesive remnant removal from the enamel surface after orthodontic bracket debonding. Materials and Methods: Forty-five extracted human upper central incisors were divided into 3 groups (n = 15) according to the kind of adhesive for bracket bonding and the use or absence of near UV light for remnant removal: BF/UV- fluorescent adhesive/UV light, BF/0-fluorescent adhesive/no UV light, and TB/0-nonfluorescent adhesive/no UV light. For all teeth, 100% of the adhesive used remained on the enamel surface after debonding. Fifteen dentists performed adhesive removal on the enamel surface using a carbide bur. The specimens were analyzed by a stereomicroscope, and the adhesive remnant percentage from each specimen was calculated. The time used by each dentist to perform the removal was recorded. The data were analyzed by one-way ANOVA and Tukey's test. Results: Significant differences were observed among groups for adhesive remnant (p=0.0008) and for time (p=0.0001). The means of adhesive remnant were BF/UV (5.84), BF/0 (34.37), and TB/0 (37.02). The mean times necessary to remove adhesive were BF/UV (1 min 40 s), BF/0 (3 min 03 s), and TB/0 (2 min 46 s). For the BF/UV group, significantly lower values of adhesive remnants and time for debonding were found (p < 0.05). Conclusion: The fluorescence-aided identification technique significantly reduced the amount of adhesive remnant, and the time necessary to perform this clinical procedure.