Desensitizing Agent Previously Applied During In-Office Bleaching: A Double-Blind Randomized Clinical Trial

Abstract Objective: To compare the clinical effect of two desensitizing agents used before the application of a bleaching gel based on 35% hydrogen peroxide (HP). Material and Methods: 30 patients were selected, and two desensitizing agents with different mechanisms of action were applied: Fluorine Neutral 2% (FN), which acts by blocking dentinal canaliculi while Potassium Nitrate 5% with 2% Sodium Fluoride (PN/SF) that acts in nerve transmission and blockade. Desensitizers were used before the application of 35% HP. For whitening, three clinical sessions were performed, with an interval of seven days, with three applications of the bleaching gel for 15 minutes, totaling 45 minutes/session. Tooth sensitivity (TS) was assessed with the numerical analog scale, and a spectrophotometer was used to obtain the color variation (ΔE). ΔE were submitted to ANOVA and Tukey test (p<0.05), and TS data were submitted to a two-way ANOVA analysis. Results: For sensitivity experience, the Tukey test indicated differences between PN/SF and the placebo I, but there was no statistically significant difference between FN and the placebo II. The TS was lower when the desensitizing gel was used during the bleaching procedure compared to after treatment, regardless of the desensitizing agents. Conclusion: PN/SF before in-office tooth bleaching can reduce TS intensity, and the use of desensitizing gel before bleaching did not affect the bleaching efficacy.

In-office dental bleaching in adolescents using 6% hydrogen peroxide with and without gingival barrier: a randomized double-blind clinical trial

Abstract At low concentrations used for in-office bleaching gels, such as 6% HP, gingival barrier continues to be performed. If we take into account that, in the at-home bleaching technique, no barrier is indicated, it seems that the use of a gingival barrier fails to make much sense when bleaching gel in low concentration is used for in-office bleaching. Objective This double-blind, split-mouth, randomized clinical trial evaluated the gingival irritation (GI) of in-office bleaching using 6% hydrogen peroxide (HP) with and without a gingival barrier in adolescents, as well as color change and the impact of oral condition on quality of life. Methodology Overall, 60 participants were randomized into which side would or would not receive the gingival barrier. In-office bleaching was performed for 50 minutes with 6% HP in three sessions. The absolute risk and intensity of GI were assessed with a visual analogue scale. Color change was assessed using a digital spectrophotometer and color guides. The impact of oral condition on quality of life was assessed using the Brazilian version of the Oral Health Impact Profile (α=0.05). Results The proportion of patients who presented GI for the "with barrier" group was 31.6% and for the "without barrier" group, 30% (p=1.0). There is an equivalence for the evaluated groups regarding GI intensity (p<0.01). Color change was detected with no statistical differences (p>0.29). There was a significant impact of oral condition on quality of life after bleaching (p<0.001). Conclusions The use or not of the gingival barrier for in-office bleaching with 6% HP was equivalent for GI, as well as for bleaching efficacy, with improvement in the impact of oral condition on quality of life.

Preparation and in vitro evaluation of polylactic acid nanoparticles containing arginine and glucose oxidase / 药学学报

Hydrogen peroxide (H2O2) and nitric oxide (NO) has a short half-life, low bioavailability, poor tumor targeting and systemic adverse reactions in the physiological environment. In this study, phacoemulsification and nano-precipitation were used to synthesize didecyl dimethyl ammonium bromide (DDAB)/polylactic acid nanoparticles (PLA), then L-arginine (L-Arg) and glucose oxidase (GOx)-loaded nanoparticles (GADP) were prepared, and the in vitro antitumor activity was investigated．The particle size, potential, embedding rate and the ability to produce H2O2/NO of the nanoparticles were investigated. Meanwhile, in vitro cell cytotoxicity against human hepatoma cells (HepG2) was evaluated．The results showed that the prepared L-Arg-DDAB/PLA (ADP) nanoparticles were spherical particles. And the particle size and zeta potential were (225.7 ± 6.33) nm and (+23.5 ± 0.12) mV, respectively. The adsorption rate of GOx was 87.23% ± 0.02%. The drug loading of L-Arg was 15.6% ± 0.22%. The pH value of glucose solution and the amount of H2O2 showed that GADP had good catalytic activity. In vitro cytotoxicity experiments showed that blank nanoparticles were nontoxic, while the drug-loaded nanoparticles presented enhanced antitumor effect on HepG2 cells. And can inhibit tumor cell migration. The low dose nano-scale NO delivery system GADP can effectively inhibit the migration of tumor cells and kill tumor cells, thus producing therapeutic benefits.

Efeito do pH do gel clareador de consultório na cor e na sensibilidade dentária / Effect of the pHof the in-office tooth bleaching gelon color and tooth sensitivity / Efecto del pH del gel blanqueador dental de consultorio sobre el color y la sensibilidad dental

Introdução:Sabe-se que a busca pela estética é algo cada vez mais crescente. Dentre os procedimentos mais procurados na odontologia estética, destaca-se o clareamento dental de consultório. Diante disso, ainda são poucos os estudos que avaliam os efeitos dos agentes clareadores de diferentes pHs na efetividade clareadora e na sensibilidade dentária.Objetivo:Avaliar a sensibilidade dentária e a eficácia clareadora de géis clareadores à base de peróxido de hidrogênio a 35% com diferentes pHs.Metodologia:Trata-se de um relato de três casos, descritivo e observacional, do tipo boca dividida (split-mouth) para cada estratégia clareadora (gel clareador com pH básico e gel clareador com pH ácido). Foram avaliados três pacientes de25, 26e 27anos de idade.Realizou-se registro de cor por meio da escala VITAClassical e avaliação da sensibilidade dentária pela escala visual analógica. Resultados:Todos os pacientes avaliados apresentaram cor A3 no registro de cor inicial e, após o clareamento dental,atingiram a cor A1. Todos relataram uma maior sensibilidade no hemiarco direito (local onde foi aplicada o gel clareador Whiteness HP que possui pH ácido. Dois pacientes relataram sensibilidade dentária no hemiarco esquerdo em que foi aplicado o gel clareador de pH básico. Conclusões:Observa-se a eficácia clínica dos géis clareadores de consultório à base de peróxido de hidrogênio a 35% na estabilidade de cor após o tratamento clareador, independente do seu pH. Ademais, nota-se que o gel clareador de pH básico promoveu menor sensibilidade pós-operatória (AU).

Introduction:It is known that the search for aesthetics is something increasingly growing. Among the most sought-after procedures in cosmetic dentistry, in-office tooth bleaching stands out. Therefore, there are still few studies that evaluate the effects of bleaching agents ofdifferent pHs on bleaching effectiveness and tooth sensitivity.Objective:To evaluate tooth sensitivity and bleaching efficacy of 35% hydrogen peroxide-based tooth bleaching gels with different pHs.Methodology:This is a report of three cases, descriptive and observational, of the split-mouth type for each bleaching strategy (bleaching gel with basic pH and bleaching gel with acidic pH). Three patients aged 25, 26 and 27 years were evaluated. Color registration was performed using the VITA Classical scale and tooth sensitivity was evaluated using the visual analogue scale.Results:All evaluated patients presented color A3 in the initial color registration and, after tooth bleaching, reached color A1. All reported greater sensitivity in the right hemi-arch (place where the Whiteness HP bleaching gel with an acid pH was applied. Two patients reported tooth sensitivity in the left hemi-arch where the basic pH bleaching gel was applied.Conclusions:The clinical efficacy of in-office tooth bleaching gels based on 35% hydrogen peroxide in terms of color stability after bleaching treatment is observed, regardless of its pH. In addition, it is noted that the basic pH bleaching gel promoted less postoperative sensitivity (AU).

Introducción: Se sabe que la búsqueda de la estética es algo cada vez más creciente. Entre los procedimientos más populares en odontología estética, se destaca el blanqueamiento dental en consultorio. Ante esto, aún existen pocos estudios que evalúen los efectos de agentes blanqueadores de diferentes pHs sobre la efectividad del blanqueamiento y la sensibilidad dental.Objetivo: Evaluar la sensibilidad dental y la eficacia blanqueadora de geles blanqueadores a base de peróxido de hidrógeno al 35 % con diferentes pH. Metodología: Este es un reporte de tres casos, descriptivo y observacional, del tipo boca partida para cada estrategia de blanqueamiento (gel blanqueador con pH básico y gel blanqueador con pH ácido). Se evaluaron tres pacientes de 25, 26 y 27 años. El registro de color se realizó con la escala clásica VITA y la sensibilidad dental se evaluó con la escala analógica visual.Resultados: Todos los pacientes evaluados presentaron color A3 en el registro de color inicial y, después del blanqueamiento dental, alcanzaron el color A1. Todos refirieron mayor sensibilidad en la hemiarcada derecha (lugar donde se aplicó el gel blanqueador de pH ácido Whiteness HP). Dos pacientes refirieron sensibilidad dental en la hemiarcadaizquierda donde se aplicó el gel blanqueador de pH básico.Conclusiones: Se observala eficacia clínica de los geles blanqueadores de consultorio a base de peróxido de hidrógeno al 35% en cuanto a la estabilidad del color tras el tratamiento blanqueador, independientemente de su pH. Además, se observa que el gel blanqueador de pH básico promovió una menor sensibilidad postoperatoria (AU).

Effects of the application of sodium ascorbate after in-office bleaching on the penetration of hydrogen peroxide, color change, and microtensile bond strength

Abstract This study aimed to evaluate the effects of the application of 10% sodium ascorbate (SA) after in-office bleaching on the penetration of hydrogen peroxide (HP) into the pulp chamber, color change, and microtensile bond strength (µTBS) to the resin-enamel interface. Thirty premolars and thirty molars were randomly divided into three groups (n = 20 each). One group was exposed to deionized water (negative control). The other two groups were bleached with 35% HP in a single session for 3x15 minutes for each application. However, in only one of them, SA was applied for 10 minutes after bleaching. After, the concentration (µg/mL) of HP in each pulp chamber was evaluated by UV-Vis spectrophotometry. Color changes (ΔEab, ΔE00, and ΔWID) were evaluated with a digital spectrophotometer before and in the first week after bleaching. After treatment, molars were restored and sectioned to obtain resin-enamel interface sticks for µTBS at a crosshead speed of 1 mm/min until failure. The HP concentration and µTBS data were analyzed using one-way ANOVA and Tukey tests, and color changes were analyzed by t-tests (α = 0.05). SA application significantly improved the µTBS values and reduced the HP concentrations within the pulp chambers (p < 0.0001). The application of SA significantly interfered with the color changes after bleaching when compared to the control group (p < 0.05). Application of 10% SA after in-office bleaching successfully reduced the penetration of HP into the pulp chamber; however, it decreased color change.

Resumo Este estudo teve como objetivo avaliar os efeitos da aplicação do ascorbato de sódio a 10% (AS) depois do clareamento em consultório na penetração do peróxido do hidrogênio (PH) na câmara pulpar, mudança de cor e resistência de união (RU) da interface resina-esmalte. Trinta pré-molares e trinta molares foram divididos aleatoriamente em três grupos (n = 20). Um grupo foi exposto em água deionizada (controle negativo). Os outros dois grupos foram clareados com 35% PH numa única sessão de 3x15 minutos para cada aplicação. Porém, só um grupo recebeu AS durante 10 minutos depois do clareamento. Depois, a concentração (µg/mL) do PH no interior de cada câmara pulpar foi avaliado com espectrofotometria UV-Vis. A mudança de cor (ΔEab, ΔE00 and ΔWID) foi avaliada como espectrofotômetro digital antes e depois de uma semana do clareamento. Após de cada tratamento, os molares foram restaurados e seccionados em espécimes com interface resina-esmalte para o teste de RU por microtração a uma velocidade de 1 mm/min até a fratura. Os dados da concentração de PH e RU foram analisados usando ANOVA de uma via e teste de Tukey, e a mudança de cor com o teste t (α = 0.05). A aplicação de AS melhorou significativamente a RU e reduziu a concentração de PH na câmara pulpar (p < 0.0001). A aplicação de AS interferiu significativamente na mudança de cor depois do clareamento comprado com o grupo controle (p < 0.05). A aplicação de SA a 10% depois do clareamento em consultório reduziu significativamente a penetração do PH na câmara pulpar e interferiu na mudança de cor.

Tooth Bleaching: A bibliometric analysis of the top 100 most-cited papers

Abstract This study analyzes the characteristics of the top 100 most-cited papers related to tooth bleaching. A literature search was performed on the Web of Science up to March 2022. The number of citations was cross-matched with the citation count on Scopus and Google Scholar. The following data were collected: number and density of citations; authorship; year and journal of publication; study design and thematic; keywords; institution and country of origin. Spearman's correlation and Poisson regression were used to determine associations between the number of citations and study characteristics. The VOSviewer software was used to generate collaborative network maps for the authors and keywords. The number of citations ranged from 66 to 450. Papers were published between 1981 and 2020. The most frequent study design and topic were laboratory-based studies and 'interaction of the bleaching agent with dental tissues', respectively. Cochran M, Loguercio AD, Matis B, Reis A, and Suliman M were the authors with the highest number of papers. The countries with the most papers were the United States of America (USA) (28%) and Brazil (20%). Indiana University and State University of Ponta Grossa were the institutions with the most papers (6% each). There was a very strong correlation among the number of citations of the three databases. The 100 most-cited papers related to tooth bleaching were mainly published by the USA and Brazil, with laboratory-based studies addressing topics related to the effects of bleaching agents on tooth structure being the most prevalent.

Resumo Este estudo analisa as características dos 100 artigos mais citados relacionados ao clareamento dental. Uma pesquisa bibliográfica foi realizada na Web of Science até março de 2022. O número de citações foi cruzado com a contagem de citações na Scopus e na Google Scholar. Foram coletados os seguintes dados: número e densidade de citações; autoria; ano e periódico de publicação; desenho do estudo e temática; palavras-chave; instituição e país de origem. A correlação de Spearman e a regressão de Poisson foram usadas para determinar associações entre o número de citações e as características do estudo. O software VOSviewer foi utilizado para gerar mapas de rede colaborativa para os autores e palavras-chave. O número de citações variou de 66 a 450. Os artigos foram publicados entre 1981 e 2020. O desenho e o tópico de estudo mais frequentes foram estudos laboratoriais e interação do agente clareador com tecidos dentários, respectivamente. Cochran M, Loguercio AD, Matis B, Reis A e Suliman M foram os autores com maior número de artigos. Os países com mais artigos foram os Estados Unidos da América (EUA) (28%) e o Brasil (20%). A Universidade de Indiana e a Universidade Estadual de Ponta Grossa foram as instituições com mais artigos (6% cada). Houve uma correlação muito forte entre o número de citações das três bases de dados. Os 100 artigos mais citados relacionados ao clareamento dentário foram publicados principalmente pelos EUA e Brasil, sendo os estudos laboratoriais que abordaram tópicos relacionados aos efeitos dos agentes clareadores na estrutura dentária os mais prevalentes.

Effect of whitening toothpastes and activated charcoal powder on enamel wear and surface roughness

Abstract This study aimed to evaluate surface roughness (Sa), roughness profile (Rv), and enamel wear after brushing with different whitening toothpastes and charcoal powders. Sixty (n = 10) bovine enamel blocks (6 × 6 × 3 mm) were randomly distributed into six groups according to toothpaste type: regular toothpaste (CONT), toothpaste containing 2% hydrogen peroxide (HP), toothpaste containing titanium dioxide (TiO2), toothpaste containing charcoal (COAL), toothpaste containing charcoal and TiO2 (COAL+TiO2), and activated charcoal powder (COAL_PWD). Each block was subjected to 30,000 reciprocal cycles at a 1:3 proportion slurry. After brushing, the blocks were analyzed using an optical profilometer to determine Sa, Rv, and enamel wear. In addition, representative 3D images of each group and wear profiles were obtained. Sa was analyzed using generalized linear models followed by Bonferroni correction, whereas Rv was analyzed using one-way analysis of variance. After brushing, COAL and COAL+TiO2 showed higher Sa values than COAL_PWD. However, no significant difference was observed in Sa between whitening toothpaste and COAL_PWD, and CONT (p > 0.05). In addition, no differences were observed among the groups in Rv (p > 0.05). Conversely, enamel wear was higher for TiO2, COAL, COAL+TiO2, and COAL_PWD than for CONT. CONT showed the least enamel wear, whereas HP showed intermediate values. Representative 3D images and line profiles showed lower step-height and lower mean surface losses for the CONT and HP groups than for the other groups. Whitening toothpastes and COAL_PWD did not increase Sa or Rv compared with CONT, while CONT demonstrated lower enamel wear.

In-office dental bleaching in adolescents using 6% hydrogen peroxide with different application tips: randomized clinical trial

Abstract Despite the availability of in-office bleaching gels with a 6% concentration of hydrogen peroxide (HP), these gels have not been evaluated in younger patients. They are commercially available with a tip, associated or not with a brush, where the tip with a brush spreads the gel over the entire surface to have a smaller thickness (thin layer) since the manufacturers indicate the application of a thin layer of gel. Objective This randomized, split-mouth, double-blind clinical trial evaluated the efficacy of in-office bleaching with 6% HP in adolescents using different application tips, as well tooth sensitivity (TS) and aesthetic self-perception. Methodology Sixty participants were randomized for 6% HP self-mixing bleaching gel tip design: without brush and with brush. In-office bleaching was performed in 3 sessions of 50 minutes. Color change was evaluated using a digital spectrophotometer (ΔE ab , ΔE 00 , and ΔWI D ) and color guide (ΔSGU), the absolute risk and intensity of TS with a visual analogue scale and aesthetic self-perception with the oral aesthetic scale (a=0.05). Results The groups achieved similar bleaching regardless of the application tip (p>0.05). However, only for ΔWI D , a significant mean difference (MD) was observed in the third week (MD 2.3; 95% CI 1.2 to 3.3; p < 0.001) and at one month (MD 1.6; 95% CI 0.6 to 2.6; p < 0.03) favoring the tip without brush. Regarding TS, 45% in the tip-without-brush group and 33% in the tip-with-brush group reported TS (odds ratio 0.61; 95% CI 0.29 to 1.28; p<0.02), with low TS intensity (MD 0.05; 95% CI -0.06 to 0.17; p>0.36). All patients reported improved aesthetic self-perception after bleaching (MD -1.3; 95% -1.8 to -0.9; p<0.001). Conclusions Regardless of the tip used bleaching with 6% HP achieved a bleaching efficacy and improved the aesthetic self-perception. However, a lower risk of TS for application using the tip with brush was observed.

Bleaching gel volume influences hydrogen peroxide diffusion, inflammation, and the presence of nitric oxide in the pulp tissue: in vitro and in vivo model

Abstract Objective To assess whether bleaching gel volume influences chromatic changes, hydrogen peroxide (HP) diffusion, inflammation, and oxidative stress in the pulp tissue. Methodology A total of 60 bovine teeth were divided into four groups, according to bleaching gel volume (n=15): without gel (WG); V30 (30 µL of 35% HP); V60 (60 µL); and V120 (120 μL). HP diffusion analysis was performed in the first session (T1). Chromatic changes (ΔE, ΔE00, and WID) were assessed after the first (T1), second (T2), third (T3) sessions, and 15 d (T4) after the end of treatment. Moreover, 20 rats were randomly divided into four groups (n=10) and their upper first molars were treated with different gel volumes: control (no treatment); V2 (2 μL of 17.5% HP); V4 (4 μL); and V8 (8 μL). After 24 h, rats were euthanized and the specimens processed for histological and immunohistochemical (nitric oxide synthase) evaluation. Data were analyzed using the Wilcoxon and Mann-Whitney tests (p<0.05). Results In vitro (bovine teeth), chromatic changes were not influenced by bleaching gel volume, showing similar values in all groups and sessions, except for the control group (p<0.05). The V120 group had the highest HP diffusion values (p<0.05). In vivo (pulp tissue), the V4 and V8 groups showed the highest inflammatory infiltrate in the pulp and significant oxidative stress (p<0.05). Conclusion The adverse effects on the dental pulp related to HP diffusion, pulp inflammation, and oxidative stress depend on bleaching gel volume, while the bleaching effect is not proportional to the volume used.

Effects of black tea tooth staining previously to 35% hydrogen peroxide bleaching

Aim: To determine if the artificial staining with black tea (BT) influences the enamel microhardness before in-office bleaching and if BT staining is necessary to evaluate the efficacy of bleaching with 35% hydrogen peroxide Methods: Enamel/dentin blocks were randomized into groups according to the staining protocol (n=5/group): (CO) control ­ maintained in artificial saliva solution (AS); (BT4) immersed in black tea solution for 4 h; (BT24) immersed in black tea solution for 24 h. After the staining protocols, all specimens were kept in AS for one week, followed by bleaching (three sessions of HP application for 40 min). Knoop surface microhardness (kgF/mm2) was determined at baseline (T0), after staining (T1), after 7 days of storage in AS (T2), and after bleaching (T3). The color (∆E00) and coordinate changes (∆L, ∆a, ∆b) were measured using a digital spectrophotometer at T0 and T3. Data were submitted to one-way (∆E00, ∆L, ∆a, ∆b) or two-way ANOVA repeated measures (kgF/mm2) and Tukey's test (a=5%). Results: The staining protocols (BT4 and BT24) promoted significantly lower microhardness (T1 and T2, p<0.05) than CO, whereas CO was the only group to maintain microhardness values over time. Bleaching promoted perceptible ∆E00 without a significant difference among the groups regardless of the staining protocol (p=0.122). CO and BT4 showed no differences in terms of ∆L and ∆a (p>0.05), but BT4 displayed a higher ∆b than CO. Conclusion:The artificial staining with BT negatively affected the enamel surface microhardness and was not essential to evaluate the efficacy of 35% hydrogen peroxide bleaching

Comparison of the effect of two disinfectants on the independent waterway disinfection of a periodontal ultrasonic scaler / 口腔疾病防治

Objective @#To compare the disinfection effect of 3% (v/v) hydrogen peroxide and 500 mg/L chlorine-containing disinfectants in the independent waterway of a periodontal ultrasonic scaler to provide a reference for clinical waterway disinfection management in stomatology departments.@*Methods @#The 18 ultrasonic scalers were randomly divided into 3 groups of 6 units: the control group, experimental group 1 (3% hydrogen peroxide disinfectant group), and experimental group 2 (500 mg/L chlorine-containing disinfectant group). The replaceable parts of the independent waterway pipes of the 3 groups of ultrasonic scalers were replaced, and the water supply was supplied with sterile distilled water (DW). In the control group, special treatment was not applied to the nonreplaceable pipe part. In experimental group 1, the 3% hydrogen peroxide was used to disinfect nonreplaceable pipelines. In experimental group 2, the nonreplaceable part was disinfected with the 500 mg/L chlorine-containing disinfectant. The water sample was taken from the outlet of the scaler working part in the three groups for monitoring before disinfection, immediately after disinfection and 10 consecutive days after disinfection. Bacteria in the water samples were cultured for the colony counts. Then, the bacterial culture data were compared between groups. The qualified criterion of the water sample was that the number of bacterial colonies was less than or equal to 100 CFU/mL. After disinfection, a bacterial species mass spectrometry identification analysis was carried out when the number of bacterial colonies in each group exceeded the standard for the first time. Biofilms from the inner wall of the tube in the three groups were observed under an electron microscope on the 10th day after disinfection.@*Results @#There were no significant differences between the three groups before disinfection (F = 2.549, P = 0.111). The number of bacterial colonies in the spout of 6 scalers in the control group all exceeded the standard, and three kinds of bacteria were cultured: Sphingomonas melonis, Herbaspirillum huttiense, and Ralstonia pickettii. Compared with those in the control group, the number of bacterial colonies in experimental group 1 decreased significantly for 1-2 days after disinfection (P<0.05) and reached the standard. On the 3rd day after disinfection, the number of bacterial colonies of group 1 increased rapidly and exceeded the standard, and three kinds of bacteria were cultured: Sphingomonas, Herbaspirillum huttiense, and Ralstonia pickettii. For experimental group 2, the number of bacterial colonies decreased significantly compared to the control group on Days 1 to 6 after disinfection, but the number of bacterial colonies increased slightly from the 7th day after disinfection and exceeded the standard. Two kinds of bacteria were cultured: Herbaspirillum huttiense and Ralstonia pickettii. The average number of bacterial colonies 10-day after disinfection in experimental group 2 was lower than that in experimental group 1(P<0.001). Under an electron microscope, the biofilm thickness of the two experimental groups was significantly lower than that of the control group. @* Conclusion @# There is water pollution in the independent waterway of a periodontal ultrasound scaler. Three percent hydrogen peroxide and 500 mg/L chlorine disinfectant both have effective disinfection effects on the outlet water of scalers, and the effect of 500 mg/L chlorine disinfectant is better than that of 3% hydrogen peroxide. The use of 3% hydrogen peroxide to disinfect periodontal ultrasound scaler-independent waterways is recommended for disinfection every other day, and disinfection once a week is recommended for the use of 500 mg/L chlorine disinfectant.

Research progress on oxidative stress regulatory mechanisms in Streptococcus mutans / 口腔疾病防治

@#The oral microecological balance is closely associated with the development of dental caries. Oxidative stress is one of the important factors regulating the composition and structure of the oral microbial community. Streptococcus mutans is closely related to the occurrence and development of dental caries. The ability of S. mutans to withstand oxidative stress affects its survival competitiveness in biofilms. The oxidative stress regulatory mechanisms of S. mutans include the synthesis of reductase, the regulation of iron and manganese uptake by metalloregulatory proteins, transcription regulator Spx, extracellular uptake of glutathione and other related signal transduction systems. The current research focuses on how S. mutans adapts to a complex external environment through an oxidative stress response and its influence on oral microecology. We can design targeted small molecular compounds for key signaling pathways to inhibit oxidative stress and weaken the virulence of S. mutans, which is important for oral microecological modulation and dental caries prevention and treatment.

Reduction of vascular reactivity in rat aortas following pilocarpine-induced status epilepticus

Abstract Objective: The authors investigated changes in vascular reactivity in rats following pilocarpine-induced status epilepticus. Method: Male Wistar rats weighing between 250g and 300g were used. Status epilepticus was induced using 385 mg/kg i.p. pilocarpine. After 40 days the thoracic aorta was dissected and divided into 4 mm rings and the vascular smooth muscle reactivity to phenylephrine was evaluated. Results: Epilepsy decreased the contractile responses of the aortic rings to phenylephrine (0.1 nM-300 mM). To investigate if this reduction was induced by increasing NO production with/or hydrogen peroxide L-NAME and Catalase were used. L-NAME (N-nitro-L arginine methyl ester) increased vascular reactivity but the contractile response to phenylephrine increased in the epileptic group. Catalase administration decreased the contractile responses only in the rings of rats with epilepsy. Conclusions: Our findings demonstrated for the first time that epilepsy is capable of causing a reduction of vascular reactivity in rat aortas. These results suggest that vascular reactivity reduction is associated with increased production of Nitric Oxide (NO) as an organic attempt to avoid hypertension produced by excessive sympathetic activation.

Comparative evaluation of therapeutic efficacy and safety of 40% hydrogen peroxide versus 80% of trichloroacetic acid in genital warts

Background: Warts are a common manifestation of infection due to HPV, prevalence more common in developing world. No modality is 100% efficacious in the management of warts. Topical therapy is more preferred method by majority of patients. Trichloroacetic acid (TCA) solution is well established modality in treatment of genital warts. Hydrogen peroxide used in higher concentrations is a good cautery agent. Aim and Objectives: The study was conducted to evaluate and compare the therapeutic efficacy and safety of 40% hydrogen peroxide solution and 80% TCA solution in genital warts. Materials and Methods: Topical 40% hydrogen peroxide and 80% TCA were used in Group A (20 patients) and Group B (20 patients), respectively, for three sittings at 2 weeks interval. Results: About 65% of the patients in TCA and 55% patients in H2O2 group had significant improvement (Grade 4 and Grade 3) (P = 0.311). Descriptive statistical methods and 2-Chi-square relation were used for analyzing data with Statistical Package for the Social Sciences (SPSS) 21 (SPSS Inc., Chicago, IL, USA). Results: About 40% H2O2 and 80% TCA, both are cost-effective and easy to use modalities with 40% H2O2 having better safety profile as compared to 80% TCA. H2O2 group showed decrease in size of lesions 63.33% versus and TCA group 70% (p value 0.311) with 10% of TCA group patients having ulcer formation versus none of the patients having significant adverse effect in H2O2 group. Conclusion: We found both the modalities to be safe and effective. However, we recommend further studies should be carried out to assess the safety and efficacy with bigger sample size and control arms for both the groups topical 40% hydrogen peroxide solution and topical 80% TCA solution.

Influence of Bleaching Agent Containing Bioactive Glass on Color and Microhardness of Bovine Enamel

To try to reduce the deleterious effects of tooth whitening, bioactive materials have been used. Forty enamel/dentin blocks were stained on dark tea and randomly assigned into four groups (n=10): control group (unbleached), HP35 % (35 % hydrogen peroxide), BG45S5 (Bioglass 45S5® incorporated into HP35 %), and BIO (Biosilicate® incorporated into HP35 %). Colorimetric analysis and microhardness evaluation was performed at baseline, 24 hours and 7 days after the final whitening session. Two-way ANOVA for repeated measures and Bonferroni test was used at a significance level of 5 %. All the coordinates (ΔL*, Δa*, Δb*, ΔE00 and WID) showed a difference between the control group and the experimental ones (p0.05), which suggest a color stability over a week. In contrast, after 7 days, the WID showed that control and PH35 % were different than the other groups (p 0.05). The microhardness did not change over time (p>0.05), except for 35 % HP. In conclusion Bioglass 45S5® and Biosilicate® prevented enamel damage without negatively affect the whitening efficacy.

Para intentar reducir los efectos nocivos del aclaramiento dental, se han usado materiales bioactivos. Cuarenta bloques de esmalte/dentina se tiñeron con té oscuro y se asignaron al azar en cuatro grupos (n=10): grupo de control (sin blanquear), HP35% (peróxido de hidrógeno al 35 %), BG45S5 (Bioglass 45S5® incorporado en HP35%) y BIO (Biosilicato® incorporado a HP35%). El análisis colorimétrico y la evaluación de la microdureza se realizaron al inicio del estudio, 24 horas y 7 días después de la última sesión de blanqueamiento. Se utilizó ANOVA de dos vías para medidas repetidas y la prueba de Bonferroni a un nivel de significancia del 5 %. Todas las coordenadas (ΔL*, Δa*, Δb*, ΔE00 y WID) mostraron diferencia entre el grupo control y el experimental (p0.05), lo que sugiere una estabilidad del color durante una semana. En cambio, a los 7 días, el WID mostró que el control y el PH35 % eran diferentes a los demás grupos (p 0.05). La microdureza no cambió con el tiempo (p>0.05), excepto para 35 % HP. En conclusión Bioglass 45S5® y Biosilicate® previnieron el daño del esmalte sin afectar negativamente la eficacia del blanqueamiento.

Ação clareadora e microbiológica do enxaguante bucal com peróxido de hidrogênio: ensaio clínico / Whitening and microbiological action of mouthwash with hydrogen peroxide: clinical trial

Introdução: os enxaguantes bucais clareadores tem sido muito utilizados, porém sua eficiência e efeitos colaterais trazem questionamentos. Objetivo: este ensaio clínico teve como objetivo avaliar se o enxaguante bucal clareador, contendo peróxido de hidrogênio a 1,5%, apresenta ação clareadora e se há algum efeito secundário na cavidade bucal. Metodologia: foram selecionados 10 voluntários com idade média de 21,5 anos, submetidos a avaliação da cor dos dentes com auxílio do espectrômetro em 3 momentos: inicial; com 15 e com 30 dias de uso do enxaguante. A avaliação dos efeitos colaterais foi realizada a partir da coleta de saliva estimulada em 4 momentos: antes e depois ao primeiro uso do produto, com 15 e com 30 dias, e realizadas as análises laboratoriais: fluxo salivar; pH; quantidade de Streptococcus mutans e de Lactobacillus. A normalidade dos dados foi verificada pelo teste de Shapiro-Wilk, comparação de cor pelo teste t dependente, comparação dos microrganismos pelos testes ANOVA de medidas repetida e Tukey. Resultados: as análises de cor dos dentes não evidenciaram nenhuma alteração significativa em nenhum dos tempos investigados. No fluxo salivar, pH e Lactobacillus não houveram alterações significativas. Na quantidade de Streptococcus mutans notou-se um aumento significativo quando comparado os valores após o primeiro uso e com 30 dias. Conclusão: a solução de enxague bucal contendo peróxido de hidrogênio a 1,5% não apresentou alteração significativa na coloração dos dentes e nenhum efeito colateral significativo na atividade cariogênica de acordo com os testes e períodos avaliados.

Introduction: whitening mouthwashes have been widely used, but their efficiency and side effects raise questions. Objective: this clinical trial aimed to assess whether the bleaching mouthwash, containing 1.5% hydrogen peroxide, has a bleaching action and whether there are any side effects in the oral cavity. Methods: 10 volunteers were selected, with a mean age of 21.5 years, who underwent tooth color evaluation with the aid of a spectrometer in 3 moments: initial; with 15 and 30 days of using the washes. The evaluation of side effects was performed from the collection of stimulated saliva in 4 moments: before and after the first use of the product, at 15 and 30 days, and laboratory analyzes were carried out: salivary flow; pH; the number of Streptococcus mutans and Lactobacillus. Normal distribution was verified with Shapiro-Wilk test, comparisons of color were performed with t-test, comparisons of the microorganisms were performed with repeated measures ANOVA and Tukey tests. Results: the analysis did not show any significant changes in any of the investigated times. There were no significant changes in the salivary flow, pH and Lactobacillus. The number of Streptococcus mutans, was noted a significant increase when comparing the values after the first use and with 30 days. Conclusion: the mouthwash containing 1.5% hydrogen peroxide was not shown any significant alterations in the color teeth. There were not significant collateral effects on the cariogenic activity according to the tests and periods evaluated.

Influence of F-18 Bioactive Glass Incorporation into Whitening Gel on Properties of Bovine Dental Enamel

ABSTRACT: Bioactive materials have shown positive results in reducing the deleterious effects of tooth whitening. However, their effects on whitening efficacy is still uncertain. Therefore, the aim of this study was to evaluate the effects of F- 18 bioactive glass incorporation into a bleaching gel on color and microhardness of enamel after tooth whitening. Thirty bovine enamel-stained specimens were randomly divided into three groups (n=10) according to the whitening protocol: control group (unbleached), HP35 % (35 % hydrogen peroxide) and F-18 (F-18 bioactive glass incorporated into HP35 %). pH, color change and microhardness analyzes were performed at baseline, 24 hours and 7 days after tooth whitening. Color evaluation showed that experimental groups were different than control group for all coordinates (p 0.05). No differences in enamel microhardness were found among the groups within the same evaluation time (p > 0.118). Regarding the intragroup comparisons, no differences were observed for control and F-18 groups (p > 0.129). It was concluded that F-18 bioactive glass incorporation did not affect the whitening efficacy and the enamel microhardness.

RESUMEN: Los materiales bioactivos han mostrado resultados positivos en la reducción de efectos nocivos del aclaramiento dental. Sin embargo, sus efectos sobre la eficacia del aclaramiento aún son inciertos. Por lo tanto, el objetivo de este estudio fue evaluar los efectos de la incorporación de vidrio bioactivo F-18 en un gel aclarador sobre el color y la microdureza del esmalte después del aclariamiento dental. Treinta especímenes bovinos teñidos con esmalte se dividieron aleatoriamente en tres grupos (n=10) de acuerdo con el protocolo de aclaramiento: grupo control (sin aclaramiento), HP35 % (peróxido de hidrógeno al 35 %) y F-18 (vidrio bioactivo F-18 incorporado en HP35 %). Se realizaron análisis de pH, cambio de color y microdureza al inicio del estudio, 24 horas y 7 días después del aclaramiento dental. La evaluación del color mostró que los grupos experimentales eran diferentes al grupo de control en todas las coordenadas (p 0,05). No se encontraron diferencias en la microdureza del esmalte entre los grupos dentro del mismo periodo de evaluación (p > 0,118). En cuanto a las comparaciones intragrupos, no se observaron diferencias para los grupos control y F-18 (p > 0,129). Se concluyó que la incorporación de vidrio bioactivo F-18 no afectó la eficacia de aclaramiento ni la microdureza del esmalte.

Influence of two remineralizing agents on bleached enamel surface morphology and mineral composition – An In Vitro study

Aim: To investigate the effects of bleaching with 35% hydrogen peroxide on the structure of tooth enamel and the role of two remineralizing agents for their potential to remineralize any damaged regions of enamel. Materials and Methods: Freshly extracted 32 mature permanent central incisors were selected and sectioned at the level of the cemento?enamel junction. The teeth were divided into four groups consisting of eight teeth each: No bleaching (control) [Group 1], bleaching with 35% hydrogen peroxide [Group 2], bleaching with 35% hydrogen peroxide followed by application of casein phosphopeptide amorphous calcium phosphate fluoride paste [Group 3], and bleaching with 35% hydrogen peroxide followed by application of xylitol?coated calcium phosphate fluoride varnish [Group 4]. The enamel surfaces were analyzed under the scanning electron microscope and quantitative energy dispersive X?ray analysis. Results: Results were statistically analyzed by one?way analysis of variance and Tukey’s posthoc test. Group 2 revealed changes in enamel surface morphology and a statistically significant decrease in mineral content. Groups 3 and 4 showed statistically significant remineralization potential. Intergroup comparison showed that samples in Group 4 had a higher mineral content compared to Group 3. Conclusions: The application of the tested remineralizing agents following bleaching was effective in repairing the enamel surface morphology with higher efficacy for the fluoride varnish product. Since bleaching regimes with high concentrations of hydrogen peroxide adversely affect the enamel surface, these findings can translate to clinical practice to reduce the long?term damaging effects of tooth bleaching

In vitro bacterial adherence on teeth submitted to whitening with musa paradisiaca / Adherencia bacteriana in vitro en dientes sometidos a blanqueamiento con musa paradisiaca

Objetive: To compare in vitro bacterial adherence on teeth submitted to whitening with 50% ethanolic extract of Musa paradisiaca and 35% hydrogen peroxide. Material and Methods: The study was experimental and used 18 premolars that were grouped into: G1 (control), G2 (50% ethanol extract of Musa paradisiaca) and G3 (35% hydrogen peroxide). The teeth were then exposed to a Streptococcus mutans culture for 24 hours, followed by centrifugation in thioglycolate broth. A culture on trypticase soy agar was done with a 1 in 100 dilution, and after 48 hours colony forming units (CFU) were counted. Statistical analysis was performed using the ANOVA test, complemented by the Bonferroni post-hoc. Results: Bacterial adherence was 77x105 CFU/ml in Group 3 using 35% hydrogen peroxide, 40x105 CFU/ml in Group 2 using 50% ethanol extract of Musa paradisiaca, and 89x104 CFU/ml in Group 1 (control). The difference between the three groups was significant (p=0.000). Conclusion: Both whitening methods cause bacterial adherence to the tooth surface, although to a lower degree with Musa paradisiaca.eses.

Objetivo: Comparar la adherencia bacteriana in vitro en dientes sometidos a blanqueamiento con extracto etanólico de Musa paradisiaca al 50% y con peróxido de hidrógeno al 35%. Material y Métodos: Comparar la adherencia bacteriana in vitro en dientes sometidos a blanqueamiento con extracto etanólico de Musa paradisiaca al 50% y con peróxido de hidrógeno al 35%.Resultados: La adherencia bacteriana fue de 77x105 UFC/ml con el peróxido de hidrógeno al 35%, de 40x105 UFC/ml con el extracto etanólico de Musa paradisiaca al 50% y de 89x104 UFC/ml con el control. La diferencia fue significativa entre los tres grupos (p=0.000). Conclusión: Ambos métodos de blanqueamiento causan adherencia bacteriana en la superficie dental, siendo menor con Musa paradisiaca.

Automedicação para clareamento dental: quais são seus riscos / Self dental whitening: what are your risks?

O escurecimento dental pode ser interpretado como um ponto de tensão visual e a busca pelo clareamento dos elementos dentários são baseados na percepção individual e imersa sobre interferências culturais que o indivíduo sofre. A preocupação com a estética do sorriso é histórica, tendo diversos mecanismos que foram usados para branquear os dentes e limpá-los (CONSOLARO, 2013). Atualmente, têm-se um forte apelo pelas mídias levando os indivíduos a buscarem meios para alcançarem o referido padrão estético (RAMOS; MONNERAT; PEREZ, 2014). A classificação dos produtos branqueadores como cosméticos traz prejuízo quanto ao uso irracional e sem supervisão, pois decorre de uma ideia diferente que se tem popularmente que apenas medicamentos podem trazer prejuízos à saúde, assim, seria melhor classificá-los como medicamentos, até porque são capazes de acarretarem mudanças fisiológicas (CONSOLARO, 2013). Diante do exposto, a FDA (Food and Drug Administration) começou a classificá-los como medicamentos ou drogas em 1991 (CONSOLARO A; FRANCISCHONE; CONSOLARO R, 2011). Os agentes branqueadores são à base de peróxido de hidrogênio (H2O2) e são encontrados em dentifrícios, enxaguantes bucais, clareamento dental de consultório e caseiro, e a própria água oxigenada usada para bochecho. Outros meios podem ser vistos na busca pelo clareamento dos dentes: o uso do bicarbonato de sódio, dentifrícios mais abrasivos e produtos com carvão ativado