Uso de Peróxido de Hidrógeno como Enjuague Bucal Previo a la Consulta Dental para Disminuir la Carga Viral de COVID-19. Revisión de la Literatura / Use of Hydrogen Peroxide as a Dental Pre-consultation Mouthwash to Decrease the Viral Load of COVID-19. Literature Review

RESUMEN: La utilización de enjuagues antisépticos previo a la atención odontológica favorecería la disminución del virus en la cavidad oral. Se ha planteado el uso de peróxido de hidrógeno preconsulta dental. Se revisaron las bases de datos PubMed, Cochrane y Elsevier publicados desde Enero 2019 a junio 2020. Los estudios que cumplieron los criterios de inclusión fueron revisados por 2 autores individualmente. Se realizó una revisión cualitativa de los datos. No existen ensayos controlados aleatorios o estudios de observación clínica sobre el efecto curativo o preventivo del peróxido de hidrógeno contra el COVID-19, pero si protocolos de ensayos clínicos que están en proceso de reclutamiento. El enjuague bucal con peróxido de hidrógeno podría ser una solución viable pre consulta dental que debe ser estudiada para reducir la carga viral del COVID-19.

ABSTRACT: The use of antiseptic rinses prior to dental care would favor the reduction of the virus in the oral cavity. The use of hydrogen peroxide prior to dental consultation has been proposed. PubMed, Cochrane and Elsevier databases published from January 2019 to June 2020 were reviewed. Studies that met the inclusion criteria were reviewed by 2 authors individually. A qualitative review of the data was performed. There are no randomized controlled trials or clinical observation studies on the curative or preventive effect of hydrogen peroxide against COVID-19, but there are clinical trial protocols that are in the process of recruitment. Hydrogen peroxide mouthwash could be a viable solution prior to dental consultation that should be studied, to reduce COVID-19 viral load.

Avaliação dos diferentes protocolos de clareamento dental caseiro (supervisionado) / Evaluation of the different protocols for at-home teeth bleaching (Supervised)

Introdução: A pigmentação dentária é causada por diversos fatores que acarretam prejuízos na estética e autoestima do paciente. A busca por um sorriso esteticamente perfeito acarretou maior demanda por procedimentos clareadores em que diferentes técnicas, tipos e concentrações de agentes clareadores podem ser utilizados na obtenção de um tratamento eficaz. Objetivo: Verificar, através de uma revisão da literatura, a eficácia, as limitações e os efeitos colaterais relacionados aos diferentes protocolos de clareamento dental caseiro. Metodologia: Foi realizada uma revisão da literatura por meio de buscas nas bases de dados PubMed/MEDLINE, LILACS, SciELO e Google Acadêmico, utilizando os seguintes descritores: "tooth bleaching" OR "supervised tooth bleaching" AND "clinical protocol". Apenas estudos experimentais, publicados nos últimos cinco anos, foram incluídos e não houve restrição quanto ao idioma. Resultados: O peróxido de hidrogênio (PH) e o peróxido de carbamida (PC) são eficazes quando administrados em concentrações de 4% a 16% com aplicações diárias que podem variar de 7 a 14 dias. O tempo de aplicação do PH é de 1 a 4 horas e do PC é de 4 a 8 horas. Géis com menores concentrações provocam menos sensibilidade dentária e irritação gengival, porém, o tempo de tratamento é geralmente prolongado. Conclusão: Para um tratamento eficaz, é indispensável um diagnóstico correto, já que o tipo de pigmento influencia sobremaneira no protocolo a ser empregado. Portanto, é fundamental conhecer a etiologia da mancha para assim estabelecer o tipo do gel, a sua concentração, o tempo e o modo de aplicação adequados.

Introduction: Dental pigmentation is caused by several factors that affect the patient's aesthetics and self-esteem. The search for an aesthetically perfect smile has led to a greater demand for bleaching procedures, in which different techniques, types, and concentrations of bleaching agents can be used to do an effective treatment. Objective: to verify, through a literature review, the application, permission, and effects related to different home tooth whitening protocols. Methodology: A literature review was carried out by searching the PubMed/MEDLINE, LILACS, SciELO, and Google Scholar databases, using the following descriptors: "tooth whitening" OR "supervised tooth whitening" AND "clinical protocol". Only experimental studies, which were published in the last five years, were included. There were no language restrictions. Results: Hydrogen peroxide (PH) and carbamide peroxide (PC) are efficient when administered in 4% to 16% with applications that can vary from 7 to 14 days. The PH application time is 1 to 4 hours and the PC is 4 to 8 hours. Gels with smaller concentrations cause less tooth sensitivity and gingival irritation; however, the treatment time is usually prolonged. Conclusion: A correct diagnosis is indispensable for an effective treatment since the type of pigment greatly affects the protocol to be used. Therefore, it is essential to know the etiology of the stain to define the type of gel, its concentration, time, and method of application.

Effect of violet LED light on in-office bleaching protocols: a randomized controlled clinical trial

Abstract Objective This study evaluated the clinical effect of violet LED light on in-office bleaching used alone or combined with 37% carbamide peroxide (CP) or 35% hydrogen peroxide (HP). Methodology A total of 100 patients were divided into five groups (n=20): LED, LED/CP, CP, LED/HP and HP. Colorimetric evaluation was performed using a spectrophotometer (ΔE, ΔL, Δa, Δb) and a visual shade guide (ΔSGU). Calcium (Ca)/phosphorous (P) ratio was quantified in the enamel microbiopsies. Measurements were performed at baseline (T 0 ), after bleaching (T B ) and in the 14-day follow-up (T 14 ). At each bleaching session, a visual scale determined the absolute risk (AR) and intensity of tooth sensitivity (TS). Data were evaluated by one-way (ΔE, Δa, ΔL, Δb), two-way repeated measures ANOVA (Ca/P ratio), and Tukey post-hoc tests. ΔSGU and TS were evaluated by Kruskal-Wallis and Mann-Whitney, and AR by Chi-Squared tests (a=5%). Results LED produced the lowest ΔE (p<0.05), but LED/HP promoted greater ΔE, ΔSGU and Δb (T 14 ) than HP (p<0.05). No differences were observed in ΔE and ΔSGU for LED/CP and HP groups (p>0.05). ΔL and Δa were not influenced by LED activation. After bleaching, LED/CP exhibited greater Δb than CP (p>0.05), but no differences were found between these groups at T 14 (p>0.05). LED treatment promoted the lowest risk of TS (16%), while HP promoted the highest (94.4%) (p<0.05). No statistical differences of risk of TS were found for CP (44%), LED/CP (61%) and LED/HP (88%) groups (p>0.05). No differences were found in enamel Ca/P ratio among treatments, regardless of evaluation times. Conclusions Violet LED alone produced the lowest bleaching effect, but enhanced HP bleaching results. Patients treated with LED/CP reached the same efficacy of HP, with reduced risk and intensity of tooth sensitivity and none of the bleaching protocols adversely affected enamel mineral content.

Association between in-office and at-home tooth bleaching: a single blind randomized clinical trial

Abstract This controlled randomized clinical trial evaluated the effect of associating at-home and in-office bleaching procedures on tooth sensitivity (TS) and bleaching effectiveness. Forty patients subjected to on session of in-office bleaching with 38% peroxide hydrogen. Subsequently, the patients were randomly allocated to receive a second session of in-office bleaching or to use a tray containing 10% carbamide peroxide delivered during 7 consecutive days. The worst TS score reported during or after each bleaching procedure was recorded using a verbal rating scale and TS risk (score different from 0) was calculated. Color changes were measured 7 days after each in-office session (for patients receiving in-office procedures only) or after the end of at-home bleaching (for the combined protocol), and 6 months after the last procedure for both bleaching protocols. Color was assessed by a spectrophotometer and by color match with the Vita Classical and Bleach guide scales. Statistical analyses were carried out to assess possible differences between the protocols regarding the outcomes and to analyze the effect of time of assessment on color changes. The bleaching protocol did not affect the risk for and the maximum level of TS reported, irrespective of the time of assessment. In the color evaluation, the bleaching protocol also did not affect the ultimate tooth color. In conclusion, after one in-office bleaching session, there was no difference in bleaching effectiveness and TS between performing a second in-office session and associating it with 1-week at-home bleaching.

Resumo Este ensaio clínico controlado e randomizado avaliou o efeito da associação de procedimentos de clareamento caseiro e de consultório na sensibilidade dental (SD) e efetividade clareadora. Quarenta pacientes receberam uma sessão de clareamento de consultório com peróxido de hidrogênio a 38%. Em seguida, os pacientes foram aleatoriamente alocados para receberem uma segunda sessão de clareamento de consultório ou para usar uma moldeira com peróxido de carbamida a 10% por 7 dias consecutivos. O pior score de SD relatada durante ou após cada procedimento clareador foi mensurado usando uma escala verbal, e o risco a SD (escore diferente de 0) foi calculado. Mudança de cor foi mensurada 7 dias após cada sessão de clareamento de consultório (para paciente submetidos a apenas procedimentos de consultório) ou após o fim do clareamento de caseiro (para o protocolo combinado) e 6 meses após o último procedimento clareador para os dois protocolos de clareamento. A cor foi mensurada através de um espectrofotômetro e pelo uso das escalas Vita Clássica e Bleach guide. As análises estatísticas foram realizadas para verificar possíveis diferenças em relação aos desfechos e para analisar o efeito do momento da mensuração nas mudanças de cor. O protocolo clareador não afetou o risco e o nível máximo de SD relatado, independentemente do tempo de avaliação. Na avaliação de cor, o protocolo clareador também não afetou a cor final dos dentes. Como conclusão, após uma sessão de clareamento de consultório, não há diferença na efetividade clareadora e na SD em realizar uma segunda sessão de consultório ou associá-la com uma semana de clareamento caseiro.

High-concentration carbamide peroxide can reduce the sensitivity caused by in-office tooth bleaching: a single-blinded randomized controlled trial

Abstract Objectives A single-blinded, randomized, parallel clinical trial evaluated the use of 37% carbamide peroxide (CP) on bleaching effectiveness and tooth sensitivity reported by patients undergoing in-office tooth bleaching, in comparison with the results of using 35% hydrogen peroxide. Material and Methods Forty patients were allocated to receive two sessions of in-office tooth bleaching using either 35% hydrogen peroxide (HP) or 37% CP. Each patient's sensitivity level was evaluated during and up to 24 h after bleaching. The effectiveness of the bleaching procedures was evaluated with a spectrophotometer one week after each session and 30 days after the last session. The impact of tooth bleaching on the patients' perceptions regarding smile changes, in addition to the bleaching procedures and their results, were also recorded. Absolute and relative sensitivity risks were calculated. Data on sensitivity level were analyzed using the Mann-Whitney or T-test, and data from the color evaluation were subjected to 2-way repeated measures ANOVA. Results The use of CP reduced the risk and level of tooth sensitivity to values close to zero, whereas the difference between the bleaching agents disappeared after 24 h. An increased bleaching effect was observed for HP, mainly due to an improved reduction of redness and yellowness. Participants perceived improved tooth bleaching for HP and reduced sensitivity for CP, but no differences regarding the comfort of the techniques were noted. Conclusions In our study, 37% CP resulted in reduced tooth sensitivity but decreased the tooth bleaching effectiveness. However, both bleaching agents resulted in high levels of patient satisfaction.

In-Office Tooth Bleaching for Adolescents Using Hydrogen Peroxide-Based Gels: Clinical Trial

Abstract The aim of the present study was to evaluate colorimetric changes and tooth sensitivity in adolescents and young patients submitted to tooth bleaching with 20% and 35% hydrogen peroxide. A randomized, controlled, clinical trial was conducted with 53 patients aged 11 to 24 years who were allocated to groups based on the use of the following commercial products: Whiteness HP - FGM® (35% hydrogen peroxide); Whiteness HP Blue Calcium - FGM® (35% hydrogen peroxide); and Whiteness HP Blue Calcium - FGM® (20% hydrogen peroxide). After the bleaching procedure, the visual analog scale was used to measure tooth sensitivity and the Vita Classical Shade guide was used to determine changes in tooth color. Statistical analysis involved the Friedman, Kruskal-Wallis and Student-Newman-Keuls tests, with p≤0.05 considered indicative of statistical significance. The addition of calcium contributed to a reduction in tooth sensitivity, especially when the lower concentration of hydrogen peroxide (20%) was used. Tooth sensitivity occurred in a transitory way and did not influence the tooth bleaching process. Significant differences in color were found after each of the two bleaching sessions. In-office tooth bleaching was considered an effective method for adolescents and young adults. Further studies in this population are necessary in order to fully evaluate the effects of bleaching in young teeth.

Resumo O objetivo do presente estudo foi avaliar alterações colorimétricas e sensibilidade dentária em adolescentes e jovens submetidos ao clareamento dental com peróxido de hidrogênio a 20% e 35%. Foi realizado um ensaio clínico controlado e randomizado com 53 pacientes, com idade entre 11 e 24 anos, que foram alocados em grupos com base nos seguintes produtos comerciais: Whiteness HP - FGM® (35% peróxido de hidrogênio); Whiteness HP Blue Calcium - FGM® (peróxido de hidrogénio a 35%); e Whiteness HP Blue Calcium - FGM® (20% de peróxido de hidrogênio). Após o procedimento de clareamento, a escala analógica visual foi utilizada para medir a sensibilidade dentária e a escala clássica Vita® foi utilizada para determinar as alterações de coloração. A análise estatística envolveu os testes de Friedman, Kruskal-Wallis e Student-Newman-Keuls, com valor de p≤0,05 considerado indicativo de significância estatística. A adição de cálcio contribuiu para uma redução da sensibilidade dentária, especialmente quando se utilizou a menor concentração de peróxido de hidrogénio (20%). A sensibilidade dentária ocorreu de forma transitória e não influenciou o processo de clareamento dos dentes. Foram encontradas diferenças significativas na cor após cada uma das duas sessões de clareamento. O clareamento dental de consultório foi considerado um método eficaz para adolescentes e adultos jovens. Estudos adicionais nesta população são necessários para avaliar completamente os efeitos do clareamento em dentes jovens.

Evaluation of an experimental rat model for comparative studies of bleaching agents

ABSTRACT Dental materials in general are tested in different animal models prior to the clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents, by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats’ vital teeth. Material and Methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals were untreated (control). The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated through histomorphometric analysis with inflammatory cell count in the coronal and radicular thirds of the pulp. Fibroblasts were also counted. Scores were attributed to odontoblastic layer and vascular changes. Tertiary dentin area and pulp chamber central area were measured histomorphometrically. Data were compared by analysis of variance and Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the coronal pulp occlusal third up to the 15-min application groups of each bleaching gel. In the groups exposed to each concentration for 30 and 45 min, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, reduction on the pulp chamber central area and enlargement of the tertiary dentin area were observed, without the detection of inflammation areas. Conclusion The rat model of extracoronal bleaching showed to be adequate for studies of bleaching protocols, as it was possible to observe alterations in the pulp tissues and tooth structure caused by different concentrations and application periods of bleaching agents.

Evaluation of an experimental rat model for comparative studies of bleaching agents

ABSTRACT Dental materials, in general, are tested in different animal models prior to their clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats’ vital teeth. Material and methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals (control) were untreated. The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated by histomorphometric analysis with inflammatory cell counting in the coronal and radicular thirds of the pulp. The counting of fibroblasts was also performed. Scores were attributed to the odontoblastic layer and to vascular changes. The tertiary dentin area and the pulp chamber central area were histomorphometrically measured. Data were compared by the analysis of variance and the Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the occlusal third of the coronal pulp until the time of 15 min for both concentrations of bleaching gels. In 30 and 45 min groups of each concentration, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, a reduction in the pulp chamber central area and an enlargement of tertiary dentin area were observed without the detection of inflammation areas. Conclusion The rat model of extra coronal bleaching showed to be adequate for bleaching protocols studies, as it was possible to observe alterations in the pulp tissues and in the tooth structure caused by different concentrations and periods of application of bleaching agents.

Analysis of the Color and Fluorescence Alterations of Enamel and Dentin Treated With Hydrogen Peroxide

Abstract: The aim of this study was to evaluate the effect of hydrogen peroxide whitening on fluorescence and color of bovine enamel and dentin. Twenty five dentin discs and 25 enamel discs, with 6 mm diameter and 1 mm thick, were obtained. Direct fluorescence (spectrofluorophotometry) and color (spectrophotometry) were assessed. After fluorescence and color baseline measurements, specimens were immersed in a 35% hydrogen peroxide (HP) solution for 1 h. This procedure was repeated after 7 days. Final fluorescence and color measurements were performed after the second immersion. Chemical characterization of 5 additional specimens was also performed. Data were submitted to repeated analysis of variance and Tukey´s test for fluorescence and unpaired t-test for color and chemical components (p<0.05). Fluorescence decreased significantly in dentin specimens after whitening. Enamel presented lower fluorescence than dentin at baseline, but this parameter did not decrease after whitening. Color changes were observed for both substrates, with significantly greater whitening effect in dentin (ΔE=10.37) (p<0.001). Whitening by hydrogen peroxide induced significant decrease in fluorescence of tooth dentin and promoted significant color changes in dentin and enamel with more accentuated outcomes in dentin.

Resumo: O objetivo deste estudo foi avaliar o efeito do clareamento com peróxido de hidrogênio na fluorescência e cor do esmalte e da dentina bovina. Vinte e cinco discos de dentina e 25 discos de esmalte, com 6 mm de diâmetro e 1 mm de espessura, foram obtidos. A fluorescência direta (Espectrofluorometria) e cor (espectrofotometria) foram avaliados. Depois da leitura inicial de cor e fluorescência, os espécimes foram imersos em solução de peróxido de hidrogénio a 35% (HP) durante 1 h. Este procedimento foi repetido após 7 dias. E as medições de fluorescência e de cor finais foram realizados após a segunda imersão. A caracterização química de 5 espécimes adicionais também foi realizada. Os dados foram submetidos à ANOVA de medidas repetidas e teste de Tukey para a fluorescência Teste e teste t não pareado para a cor e os componentes químicos (p<0,05). A fluorescência diminuiu significativamente nos espécimes de dentina após o clareamento. O esmalte apresentou fluorescência mais baixa do que a dentina na leitura inicial, mas esse parâmetro não diminuiu após o clareamento. Foram observadas alterações de cor para ambos os substratos, com significativamente maior efeito de clareamento em dentina (AE=10,37) (p<0,001). O clareamento com peróxido de hidrogênio provocou diminuição significativa na fluorescência da dentina e promoveu alterações de cor significativas na dentina e esmalte com resultados mais pronunciados em dentina.

Metronomic chemotherapy in the neoadjuvant setting: results of two parallel feasibility trials (TraQme and TAME) in patients with HER2+ and HER2− locally advanced breast cancer

Neoadjuvant chemotherapy has practical and theoretical advantages over adjuvant chemotherapy strategy in breast cancer (BC) management. Moreover, metronomic delivery has a more favorable toxicity profile. The present study examined the feasibility of neoadjuvant metronomic chemotherapy in two cohorts [HER2+ (TraQme) and HER2− (TAME)] of locally advanced BC. Twenty patients were prospectively enrolled (TraQme, n=9; TAME, n=11). Both cohorts received weekly paclitaxel at 100 mg/m2 during 8 weeks followed by weekly doxorubicin at 24 mg/m2 for 9 weeks in combination with oral cyclophosphamide at 100 mg/day (fixed dose). The HER2+ cohort received weekly trastuzumab. The study was interrupted because of safety issues. Thirty-six percent of patients in the TAME cohort and all patients from the TraQme cohort had stage III BC. Of note, 33% from the TraQme cohort and 66% from the TAME cohort displayed hormone receptor positivity in tumor tissue. The pathological complete response rates were 55% and 18% among patients enrolled in the TraQme and TAME cohorts, respectively. Patients in the TraQme cohort had more advanced BC stages at diagnosis, higher-grade pathological classification, and more tumors lacking hormone receptor expression, compared to the TAME cohort. The toxicity profile was also different. Two patients in the TraQme cohort developed pneumonitis, and in the TAME cohort we observed more hematological toxicity and hand-foot syndrome. The neoadjuvant metronomic chemotherapy regimen evaluated in this trial was highly effective in achieving a tumor response, especially in the HER2+ cohort. Pneumonitis was a serious, unexpected adverse event observed in this group. Further larger and randomized trials are warranted to evaluate the association between metronomic chemotherapy and trastuzumab treatment.

Effectiveness of nano-calcium phosphate paste on sensitivity during and after bleaching: a randomized clinical trial

The study aimed to evaluate the effectiveness of in-office bleaching and associated tooth sensitivity on application of nano-calcium phosphate paste as desensitizing agent. Bleaching was performed with 35% hydrogen peroxide gel in 40 patients who were randomly divided into placebo and nano-calcium phosphate paste groups. Bleaching efficacy (BE) was evaluated using a value-oriented Vita shade guide. Tooth sensitivity was recorded using a numeric rating scale (0–4) during bleaching and up to 48 h after each session. The primary outcome of absolute risk of tooth sensitivity was compared using the Fisher’s exact test (α = 0.05). The intensity of tooth sensitivity and the efficacy of in-office bleaching were also statistically evaluated. No significant differences in absolute risk and intensity of tooth sensitivity were detected between the groups (p = 1.0 and p = 0.53, respectively). BE was also found to be similar between the groups (p = 0.67). Although the use of a nano-calcium phosphate paste associated with fluoride and potassium nitrate did not influence the whitening outcome, but it also did not reduce bleaching-induced tooth sensitivity.

Suppression of miR-181 a attenuates H2O2-induced death of mesenchymal stem cells by maintaining hexokinase II expression

BACKGROUND: Low survival rate of transplanted cells compromises the efficacy of cell therapy. Hexokinase II (HKII) is known to have anti-apoptotic activity through its interaction with mitochondria. The objective was to identify miRNAs targeting HKII and investigate whether miRNA-mediated modulation of HKII could improve the survival of mesenchymal stem cells (MSCs) exposed to H2O2. The expression of HKII in MSCs exposed to H2O2 was evaluated, and HKII-targeting miRNA was screened based on miRNA-target prediction databases. The effect of H2O2 on the expression of the selected HKII-targeting miRNA was examined and the effect of modulation of the selected HKII-targeting miRNA using anti-miRNA on H2O2-induced apoptosis of MSC was evaluated. RESULTS: H2O2 (600 µM) induced cell death of MSCs and decreased mitochondrial HKII expression. We have identified miR-181a as a HKII-targeting miRNA and H2O2 increased the expression of miR-181a in MSCs. Delivery of anti-miR-181a, which neutralizes endogenous miR-181a, significantly attenuated H2O2-induced decrease of HKII expression and disruption of mitochondrial membrane potential, improving the survival of MSCs exposed to H2O2. CONCLUSIONS: These findings suggest that H2O2-induced up-regulation of miR-181a contributes to the cell death of MSCs by down-regulating HKII. Neutralizing miR-181a can be an effective way to prime MSCs for transplantation into ischemic tissues.

Randomized Controlled Trial of Sealed In-Office Bleaching Effectiveness

Regardless of the high success rate, patients commonly report the occurrence of tooth sensitivity during the in-office bleaching procedures. Recently, it has been demonstrated that using a customized tray (called sealed in-office bleaching technique) reduces peroxide penetration. The aim of this randomized clinical study was to evaluate tooth sensitivity and bleaching efficacy of sealed bleaching, in comparison with a conventional in-office technique. Twenty patients were randomized allocated in two groups in which 35% hydrogen peroxide gel was used in a single 45-min application. For the sealed technique, a customized bleaching tray was fabricated and carefully positioned over the bleaching agent during the session. The color was recorded at a baseline, 7 and 28 days after the bleaching session, using Vita Easy Shade spectrophotometer. Tooth sensitivity was recorded during (20 and 40 min) and immediately after the treatment using a visual analogue scale. The bleaching efficacy was evaluated by repeated-measures ANOVA, while the absolute risk of tooth sensitivity and its intensity were evaluated by Fisher's exact and Mann-Whitney tests, respectively (α=0.05). No significant difference on bleaching efficacy was observed between the conventional (7.4 and 8.1 ΔE) and sealed techniques (7.8 and 8.3 ΔE) at both evaluation periods. No significant difference was observed regarding the absolute risk of tooth sensitivity (p=0.15). Sealed technique showed a significant decrease of sensitivity intensity after 40 min (p=0.03). Sealed bleaching technique was able to reduce the sensitivity intensity during the bleaching procedure, without jeopardizing the bleaching efficacy.

Apesar da alta taxa de sucesso, os pacientes comumente relatam a ocorrência de sensibilidade dental durante os procedimentos clareadores em consultório. Recentemente, foi demostrado que o uso de uma moldeira customizada (denominada de técnica de consultório selada) reduz a penetração de peróxido. O objetivo deste ensaio clínico randomizado foi avaliar sensibilidade dentária e eficiência de clareamento do clareamento selado, em comparação com a técnica convencional de consultório. Vinte pacientes foram aleatoriamente divididos em dois grupos. Em ambos os grupos, um gel de peróxido de hidrogênio a 35% foi usado em uma simples aplicação de 45 minutos. Para a técnica selada, uma moldeira de clareamento customizada foi confeccionada e cuidadosamente posicionada sobre o agente clareador durante a sessão. A cor foi registrada no início, 7 e 28 dias após a sessão de clareamento usando a espectrofotômetro Vita easy shade. Sensibilidade dental foi registrada durante (20 e 40 minutos) e imediatamente após o tratamento usando uma escala visual analógica. A eficácia do clareamento foi avaliada por ANOVA de medidas repetidas, enquanto o risco absoluto de sensibilidade dental e a sua intensidade foram avaliados pelos testes de Fisher e Mann-Whitney, respectivamente (α=0.05). Nenhuma diferença na eficácia do clareamento foi observada entre as técnicas convencional (7.4 e 8.1 ΔE) e selada (7.8 e 8.3 ΔE) para ambos os tempos de avaliação. Nenhuma diferença foi observada em relação ao risco de sensibilidade dental (p = 0,15). A técnica selada mostrou uma significante diminuição da intensidade de sensibilidade após 40 minutos (p = 0,03). A técnica selada de clareamento reduziu a intensidade da sensibilidade durante o procedimento clareador, sem ...

Therapeutic concentration of morphine reduces oxidative stress in glioma cell line

Morphine is a potent analgesic opioid used extensively for pain treatment. During the last decade, global consumption grew more than 4-fold. However, molecular mechanisms elicited by morphine are not totally understood. Thus, a growing literature indicates that there are additional actions to the analgesic effect. Previous studies about morphine and oxidative stress are controversial and used concentrations outside the range of clinical practice. Therefore, in this study, we hypothesized that a therapeutic concentration of morphine (1 μM) would show a protective effect in a traditional model of oxidative stress. We exposed the C6 glioma cell line to hydrogen peroxide (H2O2) and/or morphine for 24 h and evaluated cell viability, lipid peroxidation, and levels of sulfhydryl groups (an indicator of the redox state of the cell). Morphine did not prevent the decrease in cell viability provoked by H2O2 but partially prevented lipid peroxidation caused by 0.0025% H2O2 (a concentration allowing more than 90% cell viability). Interestingly, this opioid did not alter the increased levels of sulfhydryl groups produced by exposure to 0.0025% H2O2, opening the possibility that alternative molecular mechanisms (a direct scavenging activity or the inhibition of NAPDH oxidase) may explain the protective effect registered in the lipid peroxidation assay. Our results demonstrate, for the first time, that morphine in usual analgesic doses may contribute to minimizing oxidative stress in cells of glial origin. This study supports the importance of employing concentrations similar to those used in clinical practice for a better approximation between experimental models and the clinical setting.

Clareamento dental - efeito da técnica sobre a sensibilidade dental e efetividade / Dental bleaching - technique effect on dental sensivity and effectiveness

O clareamento dental associado parece ser mais estável ao longo do tempo. O objetivo foi avaliar a efetividade do clareamento (ECl, sensibilidade dental (SO) e recidiva de cor (RC) no clareamento de dentes vitais. Foram distribuídos 30 pacientes em 2 grupos (n=15): clareamento associado (CA) e clareamento em consultório (CC). Foram realizadas 2 sessões de CC com PH 35% (Mix One Supreme, Villevie). O clareamento caseiro foi realizado no grupo CA com PH 6% (Mix Oay, Villevie], por 4 semanas. A cor foi registrada com a escala Vita Classical, antes e após as 2 sessões de Cc, durante o clareamento caseiro e pós-clareamento (1 semana, 1 mês e 6 meses). Os pacientes registraram a SO numa escala de 0-4. Utilizou-se os testes ANOVA e de Tukey para avaliar a EC, intensidade SO e RC. A SO foi analisada pelo teste de Fisher (p>0,05). A EC foi simi­lar para as técnicas avaliadas (p>0,05). O grupo Cc, apresentou RC significativa após 1 semana (p=0,008) e 1 mês (p=0,003), fato que não ocorreu em relação ao grupo CA, para estes períodos (p>0,05). Não houve diferença na estabilidade de cor entre os grupos 6 meses pós-clareamento (p>0,05). No CA 73% e no CC 80% dos pacientes apresentaram SO (p>0,05), sendo a maioria de intensidade leve (p>0,05). As técnicas avaliadas foram efetivas, porém o CA apresentou maior estabilidade da cor após 1 semana e 1 mês, mas não diferiu do CC 6 meses pós-clareamento. Não houve diferença de SO e de intensidade SO.

The associated dental bleaching appears to be more stable over time. The objective was to evaluate the effectiveness of bleaching (EB), tooth sensitivity (TS) and recurrence color (RC) in bleaching of vital teeth. Thirty patients were divided into 2 groups (n= 15): bleaching associated (BA) and in-office bleaching (OB). Two sessions of OB with 35 % PH (Mix One Supreme, Villevie) were performed. The home bleaching was carried out in BA with PH 6 % (Mix Oay, Villevie) for 4 weeks. The color was recorded with the Vita Classical scale before and after 2 sessions of OB during home bleaching and post - bleaching (1 week , 1 month, and 6 months) . Patients recorded the SO on a scale of 0-4. We used ANOVA and Tukey tests to assess EB, intensity of SO and RC. The SO was analyzed by Fisher (p>0.05). The EB was similar to the techniques evaluated (p>0.05). The OB group showed significant RC after 1 week (p=0.008) and 1 month (p=0.003), which did not occur in relation to the BA group, for these periods (p>0.05). No differences in color stability between groups at 6 months post-bleaching (p>0.05). In BA 73% and OB 80% of patients had SO (p>0.05), with the majority being mild (p>0.05). The evaluated techniques were effective, but the CA showed greater color stability after 1 week and 1 month, but did not differ from OB 6 months after bleaching. There was no difference in SO and intensity of SO.

High-efficiency tooth bleaching using non-thermal atmospheric pressure plasma with low concentration of hydrogen peroxide

Light-activated tooth bleaching with a high hydrogen peroxide (HP; H2O2) concentration has risks and the actual role of the light source is doubtful. The use of conventional light might result in an increase in the temperature and cause thermal damage to the health of the tooth tissue. Objective This study investigated the efficacy of tooth bleaching using non-thermal atmospheric pressure plasma (NAPP) with 15% carbamide peroxide (CP; CH6N2O3) including 5.4% HP, as compared with conventional light sources. Material and Methods Forty human teeth were randomly divided into four groups: Group I (CP+NAPP), Group II (CP+plasma arc lamp; PAC), Group III (CP+diode laser), and Group IV (CP alone). Color changes (∆E) of the tooth and tooth surface temperatures were measured. Data were evaluated by one-way analysis of variance (ANOVA) and post-hoc Tukey's tests. Results Group I showed the highest bleaching efficacy, with a ∆E value of 1.92-, 2.61 and 2.97-fold greater than those of Groups II, III and IV, respectively (P<0.05). The tooth surface temperature was maintained around 37°C in Group I, but it reached 43°C in Groups II and III. Conclusions The NAPP has a greater capability for effective tooth bleaching than conventional light sources with a low concentration of HP without causing thermal damage. Tooth bleaching using NAPP can become a major technique for in-office bleaching in the near future. .

Avaliação clínica do efeito da fonte de luz híbrida (LED/laser) na efetividade do clareamento com peróxido de hidrogênio a 35 porcentagem, sensibilidade e variação de temperatura na superfície do esmalte dental / Clinical evaluation of the effect of the hybrid light source (LED/laser) on the effectiveness of 35 per cent hydrogen peroxide bleaching, tooth sensitivity and temperature variation on the enamel surface

Tendo em vista as controvérsias relacionadas aos possíveis benefícios que o uso de fontes de luz pode proporcionar ao tratamento clareador, o objetivo desse estudo in vivo foi analisar o efeito da associação de fonte de luz híbrida (LED/laser) ao clareamento realizado com peróxido de hidrogênio a 35% no aumento da efetividade de clareamento, sensibilidade e variação de temperatura na superfície do esmalte. Após serem informados dos objetivos do estudo, 22 voluntários foram selecionados e aleatoriamente submetidos a dois tratamentos distintos, em modelo experimental de boca dividida: G1 (controle) - clareamento com peróxido de hidrogênio 35%; G2 (experimental) - clareamento com peróxido de hidrogênio a 35% associado ao uso de fonte de luz híbrida (LED/laser). A avaliação de cor foi realizada em tempos pré-determinados (antes do tratamento, 7 dias e 14 dias após a finalização do clareamento) com o auxílio de uma Escala de Cor (VITA® Classical). A sensibilidade dental foi avaliada por meio da escala visual analógica (EVA) antes, imediatamente e 24 h após o clareamento. Durante o tratamento clareador foi realizado o registro de temperatura posicionando dois canais de termopar na superfície vestibular dos dentes avaliados incisivos centrais e caninos). Os valores obtidos de alterações de cor e temperatura foram submetidos à análise estatística, ao nível de significância de 5%. Os dados de sensibilidade foram avaliados de forma descritiva. Os resultados de alteração de cor mostraram não haver diferenças de clareamento entre os dois grupos de tratamento (p = 0,177). A variação de temperatura média durante os tratamentos não foi estatisticamente associada à variação de cor (p = 0,079)...

Given the controversies related to the possible benefits that the use of light sources can provide to the bleaching treatment, the aim of this in vivo study was to analyze the effect of the combination of hybrid light source (LED/laser) to 35% hydrogen peroxide in-office bleaching on its effectiveness, tooth sensitivity and temperature variation on the enamel surface. After being informed of the objectives of the study, 22 volunteers were selected and randomly assigned to two different treatments in a split-mouth experimental model: G1 (control) - bleaching with 35% hydrogen peroxide, G2 (experimental) - bleaching with 35% hydrogen peroxide associated with the use of hybrid light source (LED/laser). The color evaluation was carried out in predetermined times (before treatment, 7 days and 14 days after completion of bleaching) with the aid of a color shade scale (VITA® Classical). Tooth sensitivity was assessed by using the visual analogue scale (VAS) before, immediately and 24 h after bleaching. During the bleaching treatment, temperature was recorded by two channels of thermocouple positioned on the buccal surface of the teeth (central incisors and canines). The values obtained for changes in color and temperature were subjected to statistical analysis, and the significance levei was set at 5%. Tooth sensitivity data were evaluated descriptively. The color change results showed no significant differences in bleaching between the two treatment groups (p = 0.177). The variation of the average temperature during the treatments was not statistically associated with color variation (p = 0.079). Immediately after bleaching it was found that 36,4% of the subjects in Group 2 had mild to moderate sensitivity. In Group 1, 45,5% of the volunteers showed moderate sensitivity. In both groups, the sensitivity of the volunteers ceased in 24 hours...

Colleras obstruidas: ¿Qué hacer?: un modelo experimental ex vivo / Clearing blocked tympanostomy tubes: an ex-vivo model

Introducción: La obstrucción del lumen de las colleras es un evento infrecuente, pero que anula la efectividad del dispositivo en la ventilación del oído medio. Existen múltiples opciones de tratamiento tópico para esta situación clínica, sin embargo, los reportes en la literatura al respecto presentan resultados contradictorios. Objetivos: Analizar la efectividad de distintos tratamientos tópicos para destapar una collera ocluida con coágulo de sangre. Material y método: Modelo experimental ex vivo, 184 tubos de ventilación obstruidos con coágulo de sangre. Tratamiento tópico, 8 grupos experimentales (agua oxigenada 3 por ciento, ácido acético 5 por ciento, ciprofloxacino 0,3 por ciento, vinagre de mesa, heparina, mezcla de H2O2/acetato 1:1, suero fisiológico 0.9 por ciento) y 2 grupos control (sin tratamiento). Revisión de permeabilidad de lumen de colleras a los 3, 7 y 10 días. Resultados: El agua oxigenada (H2O2) resulta ser el tratamiento más efectivo (88 por ciento y 92 por ciento de efectividad a los 7 y 10 días). Ciprofloxacino, vinagre de mesa, suero fisiológico y heparina son inefectivos, sin diferencias significativas con grupo control. Ciprofloxacino y suero fisiológico sedimentan más, e incluso tapan colleras previamente permeables. Conclusiones: H2O2 es un tratamiento seguro, efectivo y económico para destapar colleras obstruidas con coágulos de sangre.

Introduction: Blocked tympanostomy tubes (TT) are an uncommon event, but avoids the effectiveness of this device in middle ear ventilation. Many topical treatment options are available for this clinical situation, however, reports in literature show conflicting results. Aim: Analyze the effectiveness of various topical treatments to open blood clot blocked TT. Material and Method: Ex vivo experimental model. 184 blood clot blocked TT. Topical treatment, 8 experimental groups (3 percent hydrogen peroxide, 5 percent acetic acid, 0,3 percent ciprofloxacin, vinegar, heparin, mixture 1:1 H2O2/acetate, 0.9 percent saline) and 2 control group (no treatment). Review of tube permeability at 3, 7 and 10 days of treatment. Results: H2O2 is the most effective treatment (88 percent & 92 percent effectiveness at 7 & 10 days). Ciprofloxacin, vinegar, saline and heparin are ineffective, with no statistical differences with control group. Ciprofloxacin and saline even blocked previously opened TT. Conclusions: H2O2 is a safe, effective and economic treatment to clear blood clot blocked TT.

Ex-vivo evaluation of the intrapulpal temperature variation and fracture strength in teeth subjected to different external bleaching protocols

This study evaluated the influence of bleaching protocols on intrapulpal temperature and fracture strength of the bleached teeth. Ninety maxillary incisors were assigned to 9 groups (n=10): G1: 35 percent carbamide peroxide (35 percent CP), G2: 38 percent hydrogen peroxide (38 percent HP), G3: halogen light, G4: LED-laser, G5: 35 percent CP + halogen light, G6: 38 percent HP + halogen light, G7: 35 percent CP + LED-laser, G8: 38 percent HP + LED-laser, and G9: no treatment (control). Pulp space was widened, a thermocouple was introduced through the apex up to the pulp chamber and the temperature was recorded (°C). The fracture strength (kN) was determined using an Instron machine. Data were analyzed by ANOVA and Tukey's test (p<0.05). The halogen light alone (1.10 ± 0.24) (G3) and associated with 38 percent HP (1.15 ± 0.30) (G6) produced the highest temperature increase, statistically different (p<0.05) from the other groups. G1 (0.15 ± 0.06) and G6 (0.19 ± 0.07) produced the lowest values, statistically different (p<0.05) from G5 (0.65 ± 0.49). The bleaching protocols increased the temperature, but no increment exceeded the critical value of 5.6°C. Neither 35 percent CP nor 38 percent HP or the light sources alone altered the fracture strength of the teeth.

Este estudo avaliou a influência de protocolos de clareamento na temperatura intrapulpar e resistência à fratura de dentes clareados. Noventa incisivos superiores foram divididos em 9 grupos (n=10): G1: peróxido de carbamida a 35 por cento (PC 35 por cento), G2: peróxido de hidrogênio a 38 por cento (PH 38 por cento), G3: luz halógena, G4: LED-laser, G5: PC 35 por cento + luz halógena, G6: PH 38 por cento + luz halógena, G7: PC 35 por cento + LED-laser, G8: PH 38 por cento + LED-laser e G9: sem tratamento (controle). O canal radicular foi alargado, um termopar foi introduzido no ápice até a câmara pulpar e a temperatura foi calculada (°C). A resistência à fratura (kN) foi determinada em máquina Instron. Os dados foram analisados por análise de variância e teste de Tukey (p>0,05). A luz halógena utilizada isoladamente (1,10 ± 0,24) (G3) e associada ao PH 38 por cento (1,15 ± 0,30) (G6) proporcionaram os maiores valores de temperatura, sendo estatisticamente diferentes dos demais grupos (p<0,05). O G1 (0,15 ± 0,06) e o G6 (0,19 ± 0,07) produziram os menores valores de resistência à fratura, sendo estatisticamente diferentes (p<0,05) do G5 (0,65 ± 0,49). Os protocolos de clareamento aumentaram a temperatura, mas nenhum incremento excedeu o valor crítico de 5,6oC. O PC 35 por cento, PH 38 por cento e as fontes de luz utilizadas isoladamente não alteraram a resistência à fratura dos dentes.