Effect of conventional and power office bleaching with diode laser and led light on enamel microhardness

Aim: The present study aimed to asses enamel microhardness after office bleaching with diode laser and LED light compared to the conventional bleaching procedure. Methods: Thirty-nine human premolar teeth were collected and randomly divided into three groups regarding of the bleaching technique. Group 1: Snow O bleaching gel with LED light-curing unit; Group 2: Snow L bleaching gel with diode laser irradiation; and Group 3: Opalescence Boost bleaching gel with no light source in group 3. Enamel surface changes were evaluated in one tooth in each study group and one intact tooth as a reference under a scanning electron microscope (SEM). In the remaining samples (n=12), enamel microhardness was determined by Vickers microhardness test before and after bleaching. Data were analyzed with repeated-measures ANOVA to compare microhardness changes, followed by post hoc Tukey tests at the 0.05 significance level. Results: Enamel microhardness decreased in all the groups after bleaching, with the maximum decrease in microhardness in the Snow O bleaching group with LED light, which was significantly higher than the other groups (P=0.002). The two other groups did not exhibit any significant difference in microhardness decrease (P>0.05). Conclusion:Based on the limitations of this study, it can be concluded power bleaching with 980nm diode laser was less time-consuming compare to conventional bleaching procedure and yielded better outcomes in terms of enamel surface microhardness compared to the use of an LED light-curing unit

Avaliação in silico da afinidade de drogas ao receptor TRPA1 como preditor para o manejo farmacológico da sensibilidade provocada pelo clareamento dentário / In silico assessment of drug affinity to the TRPA1 receptor as a predictor for the pharmacological management of sensitivity caused by tooth whitening

Introdução: Reduzir a sensibilidade do clareamento dental em consultório representa um desafio para os profissionais. Pesquisadores associaram o bloqueio do receptor de dor TRPA1 com a redução da sensibilidade ao clareamento. No entanto, a afinidade química dos analgésicos/anti-inflamatórios para o TRPA1 ainda precisa ser averiguada. Objetivo: Realizar uma triagem virtual de múltiplos medicamentos (analgésicos e antiinflamatórios) para verificar a afinidade química pelo receptor TRPA1. Metodologia: A estrutura cristalina das proteínas do receptor TRPA1 foi recuperada do Protein Data Bank. Os códigos SMILES dos ligantes foram extraídos do PubChem. A energia de ligação do complexo foi obtida em ∆G - kcal/mol pelo AutoDock Vina© e replicada nos servidores SwissDock©, Dockthor© e CbDock©. LigPlus© confirmou os sítios de ligação. Resultados: Apesar dos antagonistas dos receptores analisados apresentarem alta afinidade, codeína e dexametasona apresentaram regularidade em todos os servidores, mesmo apresentando valores de energia de ligação de -7,9 kcal/mol para codeína e -8,1 kcal/mol para dexametasona. Conclusão: A codeína e a dexametasona podem ser drogas potenciais para controlar a sensibilidade ao clareamento dental caso atinjam o receptor TRPA1 da polpa dentária (AU).

Introduction: Reducing in-office tooth bleaching sensitivity represents a challenge for professionals. Researchers have associated the block of the pain receptor TRPA1 with reducing bleaching sensitivity. However, the chemical affinity of analgesic/antiinflammatory drugs to the TRPA1 needs to be verified. Objective: To perform a virtual screening of multiple drugs (analgesic and anti-inflammatory drugs) to verify chemical affinity for the TRPA1 receptor. Methodology: The crystal structure of the TRPA1 receptor proteins was retrieved from the Protein Data Bank. The SMILES codes of the ligands were extracted from PubChem. The binding energy of the complex was obtained in ∆G - kcal/mol by AutoDock Vina© and replicated in the webservers SwissDock©, Dockthor©, and CbDock©. LigPlus© confirmed the binding sites. Results: Although the receptor antagonists analyzed showed high affinity, codeine and dexamethasone showed regularity among all servers, even showing binding energy values of -7.9 kcal/mol for codeine and -8.1 kcal/mol for dexamethasone. Conclusion: Codeine and dexamethasone may be potential drugs to manage tooth bleaching sensitivity if they reach the dental pulp TRPA1 receptor (AU).

Effect of penetrating resin on the surface structure, microhardness and color of enamel after bleaching / 中华口腔医学杂志

Objective: To investigate the effect of permeable resin on the surface structure, microhardness and color of tooth enamel after bleaching. Methods: Premolars extracted for orthodontic needs were selected (provided by the Department of Oral and Maxillofacial surgery of the first affiliated Hospital of Zhengzhou University) and randomly divided into A, B and C 3 groups. Each group was randomly divided into control subgroup, resin subgroup, bleaching subgroup and combined subgroup. Samples in the control subgroup did not receive any treatment. Those in the bleaching subgroup and combined subgroup were treated with cold light whitening. Those in the resin group and combined group were treated with permeable resin. Samples in the group A were observed by scanning electron microscope immediately after treatment and 2 weeks after treatment, and the microhardness of samples in the group B was measured before treatment, immediately after treatment and 2 weeks after treatment (the sample size of each time point was 8 in each subgroup). In group C, chromaticity was measured and chromatic aberration (ΔE value) was calculated before treatment, immediately after treatment and 1 and 2 weeks after treatment (10 samples in each subgroup). Results: Scanning electron microscope showed that the enamel surface of the resin subgroup and the combined group was smooth immediately after treatment, which was basically the same as that of the control subgroup, but covered with resin, and microporous defects and mineral deposits could be seen on the surface of the bleaching subgroup. Two weeks after treatment, the enamel surface of each subgroup was smooth, there was no obvious difference. Immediately after treatment, the microhardness of the control subgroup, resin subgroup, bleaching subgroup and combined subgroup were (354±33), (364±21), (411±30) and (350±17) HV, respectively (F=9.39,P<0.05). The microhardness of the bleaching subgroup was significantly higher than that of the other subgroups (P<0.05). There was no significant difference in microhardness among the four subgroups before treatment and 2 weeks after treatment (F=0.34, 2.75, P>0.05). Immediately after treatment, the ΔE values of the control subgroup, resin subgroup, bleaching subgroup and combined subgroup were 0.00±0.00, 2.29±1.86, 7.20±1.94 and 8.00±0.88, respectively (F=74.21,P<0.05); except that there was no significant difference between bleaching subgroup and combined subgroup (P>0.05), there were significant differences among the other subgroups (P<0.05). There was no significant difference in ΔE value among control subgroup, resin subgroup and bleaching subgroup at each time point (F=1.66, 0.30, 0.96, P>0.05). The difference in the combined subgroup immediately after treatment was significantly higher than that at 1 and 2 weeks after treatment (t=4.73, 4.23,P<0.05), but there was no significant difference between 1 and 2 weeks after treatment (t=0.75, P>0.05), and the color tended to be stable. Conclusions: When whitening healthy enamel, simple cold light whitening or cold light whitening combined with permeation resin can achieve whitening effect.

Estabilidad del color en el blanqueamiento intracoronal / Color stability in intracoronal whitening

RESUMEN Introducción: El blanqueamiento intracoronal es una alternativa mínimamente invasiva que permite devolver el color a dientes no vitales tincionados. La estabilidad del color logrado es fundamental para evaluar la predictibilidad de este tipo de tratamiento. Objetivo: Evaluar la estabilidad del color 3 años después del blanqueamiento intracameral con peróxido de hidrógeno y carbamida a diferentes concentraciones. Métodos: Se utilizaron 44 premolares extraídos por indicación ortodóncica, los cuales fueron tratados endodónticamente y pigmentados artificialmente con cromógenos sanguíneos. Las muestras fueron divididas aleatoriamente en 4 grupos de estudio (n = 11) siendo: grupo A: peróxido de carbamida 37 por ciento, grupo B: peróxido de hidrógeno 35 por ciento, grupo C: peróxido de carbamida 100 por ciento y grupo D: control; para luego realizar 4 aplicaciones de agente blanqueador con un intervalo de 4 días entre cada aplicación. El registro del color se realizó mediante espectrofotometría, lo que permitió obtener los valores CIE L*a*b* para calcular la variación total de color entre los parámetros iniciales y finales del tratamiento, así como el control a los 3 años. Resultados: Los resultados fueron analizados mediante las pruebas de Shapiro-Wilks, ANOVA y Mann-Whitney, sin registrar diferencias significativas en la variación total de color al control de los 3 años (p > 0,05). Conclusión: Los resultados del blanqueamiento intracoronal, independiente del tipo y concentración del agente utilizado en este estudio son estables en el tiempo y cualquier variación regresiva de color debe ser atribuida a factores extrínsecos(AU)

ABSTRACT Introduction: Intracoronal whitening is a minimally invasive procedure to restore natural color to stained non-vital teeth. The color stability achieved is fundamental to evaluate the predictability of this type of treatment. Objective: Evaluate color stability 3 years after intracameral whitening with carbamide and hydrogen peroxide at various concentrations. Methods: A total 44 premolars were used which had been extracted by orthodontic indication. The premolars were treated endodontically and artificially pigmented with blood chromogenes. The samples were randomly divided into 4 study groups (n = 11): Group A: 37 percent carbamide peroxide, Group B: 35 percent hydrogen peroxide, Group C: 100 percent carbamide peroxide and Group D: control. Four applications were then made of the whitening agent with a 4-days' separation between them. Color was recorded by spectrophotometry, obtaining the values CIE L*a*b* to estimate total color variation between the initial and final parameters of the treatment, as well as control at 3 years. Results: The results were analyzed with Shapiro-Wilk, ANOVA and Mann-Whitney tests, not finding any significant differences in total color variation with respect to the 3 years' control (p > 0.05). Conclusion: The results of the intracoronal whitening studied are stable throughout time, regardless of the type and concentration of the agent used, and any regressive color variation should be attributed to extrinsic factors(AU)

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.

Experimental gel containing bioactive glass-ceramic to minimize the pulp damage caused by dental bleaching in rats

Abstract Objectives This study evaluated if the use of a bioactive glass-ceramic-based gel, named Biosilicate (BS), before, after or mixed with bleaching gel, could influence the inflammation of the dental pulp tissue of rats' molars undergoing dental bleaching with hydrogen peroxide (H2O2). Methodology The upper molars of Wistar rats (Rattus norvegicus, albinus) were divided into Ble: bleached (35% H2O2, 30-min); Ble-BS: bleached and followed by BS-based gel application (20 min); BS-Ble: BS-based gel application and then bleaching; BS/7d-Ble: BS-based gel applications for 7 days and then bleaching; Ble+BS: blend of H2O2 with BS-based gel (1:1, 30-min); and control: placebo gel. After 2 and 30 days (n=10), the rats were euthanized for histological evaluation. The Kruskal-Wallis and Dunn statistical tests were performed (P<0.05). Results At 2 days, the Ble and Ble-BS groups had significant alterations in the pulp tissue, with an area of necrosis. The groups with the application of BS-based gel before H2O2 had moderate inflammation and partial disorganization in the occlusal third of the coronary pulp and were significantly different from the Ble in the middle and cervical thirds (P<0.05). The most favorable results were observed in the Ble+BS, which was similar to the control in all thirds of the coronary pulp (P>0.05). At 30 days, the pulp tissue was organized and the bleached groups presented tertiary dentin deposition. The Ble group had the highest deposition of tertiary dentin, followed by the Ble-BS, and both were different from control (P<0.05). Conclusion A single BS-based gel application beforehand or BS-based gel blended with a bleaching gel minimize the pulp damage induced by dental bleaching.

Does the use of reservoirs have any impact on the efficacy of at-home bleaching? a systematic review

Abstract To answer the following focused question through a systematic review: "Are the risk and intensity of tooth sensitivity (TS) and bleaching efficacy different between adult patients who undergo at-home bleaching using trays with reservoirs and those who use trays without reservoirs?". A comprehensive search was performed in the MEDLINE via PubMed, Scopus, Web of Science, Latin American and Caribbean Health Sciences Literature database, Brazilian Library in Dentistry, Cochrane Library, and grey literature without restrictions. Abstracts from conferences; unpublished and ongoing trial registries, dissertations and theses (ProQuest Dissertations and Periódicos Capes Theses databases) were searched. Only randomized clinical trials (RCTs) were included. We used the Risk of Bias tool (RoB) from the Cochrane Collaboration for quality assessment. After the removal of duplicates, title and abstract screening and full-text examination, nine RCTs remained for qualitative analyses. The great majority of the studies did not report the method of randomization, allocation concealment, and examiner blinding during color assessment. From the nine studies, eight were at unclear risk of bias. In regard to color change, four studies reported no change and two reported improved color change with reservoirs. Only four studies recorded tooth sensitivity and they reported no significant differences. Only one study reported greater gingival irritation with reservoirs. Lack of data reporting prevented us from running a meta-analysis. Further well-designed RCT should be conducted to answer this research question. So far there is not evidence to support that reservoirs in bleaching trays improve color change. PROSPERO - CRD42016037628

Resumo Para responder a seguinte questão de pesquisa através de uma revisão sistemática: "O risco e a intensidade de sensibilidade dentária (SD) e eficácia de clareamento são diferentes entre pacientes adultos que realizam clareamento caseiro usando moldeiras com reservatórios e aqueles que usam moldeiras sem reservatórios?". Uma pesquisa abrangente foi realizada no MEDLINE via PubMed, Scopus, Web of Science, Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS), Biblioteca Cochrane e literatura cinzenta, sem restrições. Os resumos da conferência anual da Associação Internacional para Pesquisa Dental além de estudos registrados ou em andamento também foram pesquisados. Dissertações e Teses foram pesquisados utilizando o Capes Journal Dissertações e Teses ProQuest. Apenas ensaios clínicos randomizados (ECR) foram incluídos. Usamos a ferramenta Risk of Bias (RoB) da Cochrane para avaliação de qualidade. Após a remoção de duplicatas, triagem de título e resumo e exame de texto completo, nove ECRs permaneceram para análises qualitativas. A grande maioria dos estudos não relatou o método de randomização, ocultação de alocação e cegamento do examinador durante a avaliação de cores. Dos nove estudos, oito estavam sob risco claro de viés. Em relação à mudança de cor, quatro estudos não relataram nenhuma mudança e dois relataram melhora na mudança de cor com reservatórios. Apenas quatro estudos registraram a sensibilidade dentária e não relataram diferenças significativas. Apenas um estudo relatou maior irritação gengival com reservatórios. A falta de relatórios de dados nos impediu de executar uma meta-análise. Outros ECR bem desenhados devem ser conduzidos para responder a esta questão de pesquisa. Até agora não há evidências que sustentem que reservatórios em moldeiras de clareamento melhorem a mudança de cor. PROSPERO - CRD42016037628

Effect of dental bleaching on pulp oxygen saturation in maxillary central incisors - a randomized clinical trial

Abstract Objective To assess pulp oxygen saturation levels (SaO2) in maxillary central incisors after dental bleaching. Materials and Methods 80 participants (160 teeth) were randomly allocated to four groups: G1 In-office bleaching with two applications of 35% hydrogen peroxide (HP) (20 minutes), followed by at-home bleaching with 10% carbamide peroxide (CP) (2 hours/day for 16 days); G2 - Same protocol as G1, plus desensitizing toothpaste; G3 - In-office bleaching with 35% HP and one application of placebo gel (20 minutes), followed by at-home bleaching with 10% CP (2 hours/day for 16 days); and G4 - Same protocol as G3, plus desensitizing toothpaste. Pulp SaO2 levels were measured before (T0) and immediately after (T1) in-office bleaching; on the 5th (T2), 8th (T3), 12th (T4), and 16th days of at-home bleaching (T5); and on the 7th (T6) and 30th (T7) days. Mean (SD) pulp SaO2 levels were compared within groups by generalized estimating equations (GEE) and Student's t-test (P<0.05). Results Mean pulp SaO2 at T0 was 84.29% in G1, 84.38% in G2, 84.79% in G3, and 85.83% in G4. At T1, these values decreased to 81.96%, 82.06%, 82.19%, and 81.15% in G1, G2, G3, and G4 respectively, with significant difference in G4 (P<0.05). During home bleaching, pulp SaO2 levels varied in all groups, with 86.55%, 86.60%, 85.71%, and 87.15% means at T7 for G1, G2, G3, and G4, respectively; G2 presented significant difference (P<0.05). Conclusions Pulp SaO2 level in maxillary central incisors was similar at baseline, reducing immediately after in-office bleaching, regardless of using desensitizing toothpaste and increasing at 30 days after dental bleaching.

In vivo study of the action of a topical anti-inflammatory drug in rat teeth submitted to dental bleaching

Abstract Bleaching gel containing hydrogen peroxide (H2O2) cause damages in pulp tissue. This study investigated the action of a topical anti-inflammatory, the Otosporin®, in rats' bleached teeth with the null hypothesis of which the Otosporin® is no able to minimize the pulp inflammation that bleaching gel generates. The rat's molars were divided into groups: BLE: bleached (35% H2O2 concentration /single application of 30 min); BLE-O: bleached followed by Otosporin® (10 min); and control: placebo gel. In the second day after dental bleaching, the rats were killed, and the jaws were processed for hematoxylin-eosin and immunohistochemistry analysis for tumor necrosis factor alpha (TNF-α), interleukin (IL)-6 and IL-17. The data collected were subjected to Kruskal-Wallis and Dunn statistical tests with at a 5% level of significance (p<0.05). The BLE group had moderate to strong inflammation in the occlusal third of the coronary pulp, with necrotic areas; and BLE-O, mild inflammation (p<0.05). There was a significant difference in the occlusal and middle thirds of the coronary pulp between the BLE with BLE-O and control groups (p<0.05). There was no difference in the cervical third (p>0.05). The BLE group had a high immunoexpression of TNF-α than BLE-O and control groups (p<0.05), with moderate and mild immunoexpression, respectively. Regarding IL-6 and IL-17, the BLE group had higher immunoexpression than control (p<0.05); the BLE-O was similar to the control (p>0.05). The topical anti-inflammatory Otosporin® can reduce pulp inflammation after dental bleaching in the rat teeth.

Resumo O gel clareador à base de peróxido de hidrogênio (H2O2) causa danos ao tecido pulpar. Este estudo investigou a ação de um anti-inflamatório tópico, o Otosporin®, nos dentes de ratos clareados com a hipótese nula de que o Otosporin® não é capaz de minimizar a inflamação da polpa gerada pelo gel clareador. Os molares dos ratos foram divididos em grupos: ClA: clareado (H2O2 a 35% / aplicação única de 30 min); CLA-O: clareado seguido do Otosporin® (10 min); e controle: gel placebo. No segundo dia após a clareação dentária, os ratos foram mortos e suas maxilas foram processadas para análise de hematoxilina-eosina e imunohistoquímica para o fator de necrose tumoral alfa (TNF-a), interleucina (IL)-6 e IL-17. Os dados coletados foram submetidos aos testes estatísticos de Kruskal-Wallis e Dunn com um nível de significância de 5% (p<0,05). O grupo CLA apresentou inflamação moderada à severa no terço oclusal da polpa coronária, com áreas necróticas; e CLA-O, inflamação leve (p<0,05). Houve diferença significativa nos terços oclusal e médio da polpa coronária entre o grupo CLA com os grupos CLA-O e controle (p<0,05). Não houve diferença no terço cervical (p>0,05). O grupo CLA apresentou maior imunoexpressão para TNF-a comparado aos grupos CLA-O e controle (p<0,05), com imunoexpressão moderada e leve, respectivamente. Em relação a IL-6 e IL-17, o grupo CLA apresentou maior imunoexpressão comparado ao controle (p<0,05); o CLA-O foi semelhante ao controle (p>0,05). O anti-inflamatório tópico Otosporin® pode reduzir a inflamação pulpar após clareação em dentes de ratos.

Effect of mangosteen peel extract as an antioxidant agent on the shear bond strength of orthodontic brackets bonded to bleached teeth

Abstract Introduction: The number of patients who seek orthodontic treatment that may have a history of tooth bleaching is increasing over the time. Bleaching may influence the decrease of the bond strength of orthodontic brackets. Objective: To determine and prove the effect of mangosteen peel (MP) extract to reverse the reduced shear bond strength (SBS) of orthodontic brackets after bleaching. Methods: A total of 150 maxillary first premolar teeth were randomly divided into 6 experimental groups as follow (n=25): negative-control (N: no bleaching), positive-control (P: bleaching + no treatment), and the treatment groups (bleaching + 10% sodium ascorbate (SA), 10% (MP-10), 20% (MP-20) and 40% (MP-40) MP extract gel). After treatment, the brackets were bonded with the resin-modified glass ionomer cement, SBS testing was performed using universal testing machine, and the adhesive remnant index (ARI) was examined using stereoscopic microscope after debonding. The SBS data were analyzed by analysis of variance (Anova) and the Tukey test. For the ARI, the Kruskal-Wallis test was performed. Result: There was significant SBS difference (p< 0.001) between various groups. The group without bleaching showed significantly higher SBS (8.19 ± 2.26 MPa) compared to others, while SBS in the group treated with 40% MP gel was significantly higher (7.93 ± 1.92 MPa) than other groups treated with antioxidants. The failure of orthodontic brackets bonded after bleaching and treatment using MP extract occurred at the enamel-adhesive interface. Conclusion: The application of MP extract as an antioxidant after bleaching was effective in reversing the reduced shear bond strength of orthodontic brackets after bleaching.

Resumo Introdução: o número de pacientes que procuram o tratamento ortodôntico e têm histórico de clareamento dentário tem aumentado. O clareamento pode levar à diminuição da resistência adesiva dos braquetes ortodônticos. Objetivos: comprovar a efetividade do extrato de casca de mangostão (CM) em reverter a diminuição da resistência ao cisalhamento de braquetes ortodônticos colados após o clareamento. Métodos: 150 primeiros pré-molares superiores foram aleatoriamente divididos em seis grupos experimentais (n= 25): controle negativo (grupo N, sem clareamento), controle positivo (grupo P, clareamento + sem tratamento) e os grupos com tratamento (clareamento + ascorbato de sódio a 10% [grupo AS], gel de extrato de CM a 10% [grupo CM-10], a 20% [grupo CM-20] e a 40% [grupo CM-40]). Após o tratamento, os braquetes foram colados com cimento de ionômero de vidro modificado por resina e, depois, fez-se o teste de resistência ao cisalhamento (SBS) em uma máquina universal de ensaios. Após a descolagem dos braquetes, verificou-se o índice de adesivo remanescente (ARI), com o uso de um microscópio estereoscópico. Os dados da SBS foram submetidos a uma análise de variância (ANOVA) e ao teste de Tukey. Para o ARI, foi utilizado o teste de Kruskal-Wallis. Resultados: houve diferença significativa na SBS (p< 0,001) entre os diferentes grupos. O grupo sem clareamento mostrou resistência ao cisalhamento significativamente maior (8,19 ± 2,26 MPa) do que os outros grupos, enquanto a resistência ao cisalhamento do grupo tratado com o gel de extrato de CM a 40% foi significativamente maior (7,93 ± 1,92 MPa) do que nos outros grupos tratados com antioxidantes. A falha na colagem dos braquetes ortodônticos após o clareamento e tratamento com o extrato de CM ocorreu na interface adesivo/esmalte. Conclusão: a aplicação do extrato de CM como agente antioxidante foi efetiva em reverter a diminuição, que ocorre após o clareamento dentário, na resistência ao cisalhamento da colagem de braquetes ortodônticos.

Análise de citotoxicidade, desmineralização e potencial clareador de géis clareadores experimentais, baseado em peróxido de carbamida 15% adicionados de nano-hidróxiapatita / Analysis of cytotoxicity, demineralization and bleaching potential of experimental bleaching gels, based on 15% carbamide peroxide added with nanohydroxyapatite

O clareamento dental é considerado um procedimento muito seguro, de efeito rápido e agradável, tornando-se um dos procedimentos mais realizados na odontologia. Contudo, o mesmo apresenta alguns efeitos colaterais, sendo o principal deles a sensibilidade dental, que pode ser causada pela citotoxidade, pela desmineralização, pela geração de espécies reativas do oxigênio na polpa dental e pela degradação da região interprismática facilitando o estimulo nos túbulos dentinários. Diante disso, a presente pesquisa avaliou a desmineralização, a citotoxidade e o potencial clareador de géis clareadores experimentais baseados em peróxido de carbamida (PC) 15%, adicionados de 5% e 10% de nano partículas de hidroxiapatita (n-Hap). Para a avaliação cromática foram utilizados 36 incisivos bovinos divididos em 3 grupos: Grupo1 PC 15%, Grupo 2 PC 15% adicionado 5% nHap e grupo 3 PC 15% com 10% n-Hap, mensurando a cor antes e depois do procedimento terapêutico clareador com auxilio de um espectrofotômetro. As coordenadas do CIELAB foram analisadas para verificação da diferença de cor (ΔE) obtida entre os grupos e dentro do próprio grupo (L*) e, após a analise estatística, foi verificado que todos os géis foram capazes de clarear e não houve diferenças entre os grupos. A citotoxidade foi verificada através da absorbância das células viáveis após o tratamento com o MTT e 1:800 das preparações de agente clareador e gel contendo 5% e 10% de n-Hap aplicadas sobre células L929. Nesse caso os grupos foram desiguais estatisticamente, apresentando o PC 15% como o mais tóxico, seguido do PC 15% adicionado de 10% de n-Hap e o melhor resultado foi obtido pelo gel acrecido de 5% de n-Hap. A análise do conteúdo mineral foi realizada pela fluorescência de raios X por dispersão de energia, onde foi necessário o uso de 15 dentes bovinos, que tiveram seus terços médios seccionados, embutidos em resina epóxi e planificados, e foram dividos em grupos de 5 CPs. Cada CP foi aferido em 8 pontos diferentes antes e depois, nos mesmos pontos da terapia clareadora. Foi então verificado que os géis experimentais apresentaram menor perda de Ca e P. No entanto, não houve diferenças estatísticas entre os grupos 2 e 3. Diante das limitações do presente estudo in vitro é possível concluir que os géis experimentais contendo n-Hap foram eficazes em reduzir a citotoxidade e desmineralização sem perder a eficácia da terapia clareadora

Dental whitening is considered a very safe, quick and pleasant procedure, making it one of the most accomplished procedures in dentistry. However, it has some side effects, the main one being sensibility, which can be caused by cytotoxicity, demineralization, oxygen arrival in the dental pulp and the degradation of the interprismatic region facilitating the stimulation in the dentin tubes. Therefore, the present study evaluated the demineralization, cytotoxicity and bleaching potential of 15% carbamide peroxide-based (PC) based bleaching gels added with 5% and 10% nano-hydroxyapatite (n-Hap) particles. For the chromatic evaluation, 36 bovine incisors were divided into 3 groups: Group 1 PC 15%, Group 2 PC 15% added 5% nHap and group 3 PC 15% with 10% n-Hap, measuring the color before and after the the CIELAB coordinates were analyzed to verify the color difference (Δe) obtained between the groups and within the group (L *). After the statistical analysis it was verified that all the gels were able to lighten and there were no differences between the groups. Cytotoxicity was verified by optical density of viable cells after treatment with MTT and 1: 800 of the bleach and gel preparations containing 5% and 10% nHap applied in L929 cells. In this case, the groups were statistically unequal, presenting 15% PC as the most toxic, followed by PC 15% added with 10% n-Hap and the best result was obtained by the 5% n-Hap increased gel. The mineral content analysis was performed by X-ray Fluorescence by energy dispersion, where it was necessary to use 15 bovine teeth, which had their middle sections sectioned, embedded in epoxy resin and planned, and were divided into groups of 5 CPs, each CP was measured at 8 different points before and after, at the same points of the bleaching therapy, then it was verified that the experimental gels presented a lower loss of Ca and P, however there were no statistical differences between groups 2 and 3. On the face of the limitations of the present in vitro study, it is possible to conclude that the experimental gels were effective in reducing the cytotoxicity and demineralization without losing the effectiveness of the bleaching therapy.

In-office tooth bleaching with 38% hydrogen peroxide promotes moderate/severe pulp inflammation and production of ll-1ß, TNF-ß, GPX, FGF-2 and osteocalcin in rats

Abstract Objectives: To study the intensity of inflammatory infiltrate and production of interleukin-1β (ll-1β), tumor necrosis factor-β (TNF-β), fibroblast growth factor-2 (FGF-2), glutathione peroxidase (GPX), and osteocalcin in response to in-office tooth bleaching in rats. Material and Methods: Twenty male Wistar rats were randomized into four groups (n=5) according to the received treatment (tooth bleaching or no treatment - control) and the period of euthanasia after treatment (24 h or 10 days). We performed tooth bleaching using a 38% hydrogen peroxide gel on maxillary and mandibular incisors. After euthanasia, incisors (20 per group) were processed for histological analysis, immunohistochemistry staining of ll-1β, TNF-β, FGF-2 and GPX and osteocalcin by immunofluorescence. We analyzed data using the Mann-Whitney and Kruskal-Wallis/Dunn tests (p<0.05). Results: The bleached groups presented statistically significant differences regarding the pulp inflammation stage compared with the control groups. Bleached teeth showed moderate/severe inflammatory infiltrate and control groups presented absent inflammatory cells or a negligible number of mononuclear cells (p<0.001) at two times (24 h and 10 days). There was strong staining for ll-1β, TNF-β, and GPX in bleached groups at 24 h and strong staining for ll-1β, TNF-β, GPX and FGF-2 at 10 days. After 10 days of tooth bleaching, the bleached group showed a statistically superior amount of osteocalcin than the other groups (p<0.01). Conclusions: Tooth bleaching with 38% hydrogen peroxide causes severe pulp inflammation, but characteristics of tissue repair after 10 days.

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.

Effects of experimental bleaching agents on the mineral content of sound and demineralized enamels

Abstract High concentrations of hydrogen peroxide can cause adverse effects on composition and structure of teeth. However, the addition of calcium and fluoride in bleaching agents may reduce enamel demineralization. Objective: To evaluate chemical changes of sound and demineralized enamels submitted to high concentrations of hydrogen peroxide containing fluoride (F) or calcium (Ca). Material and Methods: Enamel blocks of bovine incisors with standard dimensions were obtained and half of them were submitted to pH-cycling to promote initial enamel caries lesions. Sound and demineralized enamel samples were divided into (n=10): (C) Control (no whitening treatment); (HP) 35% hydrogen peroxide; and two experimental groups: (HPF) 35% HP+0.2% F and (HPC) 35% HP+0.2% Ca. Experimental groups were submitted to two in-office bleaching sessions and agents were applied 3 times for 15 min to each session. The control group was kept in remineralizing solution at 37°C during the bleaching treatment. The surface mineral content of sound and demineralized enamels was determined through Fourier Transform Raman spectroscopy (FT-Raman), Energy dispersive Micro X-ray fluorescence spectroscopy (μ-EDXRF); and the subsurface, through cross-sectional microhardness (CSMH). In addition, polarized light microscopy (PLM) images of enamel subsurface were observed. Results: According to three-way (FT-Raman and μ-EDXRF analyses) or two-way analysis of variance (ANOVA) (CSMH) and Tukey test (α=5%), the calcium or fluoride added to high-concentrated bleaching agents increased phosphate and carbonate concentrations on sound and demineralized enamels (p<0.05). However, HPC and HPF were unable to completely reverse the subsurface mineral loss promoted by bleaching on sound and demineralized enamels. The calcium/ phosphate (Ca/P) ratio of sound enamel decreased after HP treatment (p<0.001). Conclusion: Even though experimental bleaching agents with Ca or F reduced mineral loss for both sound and demineralized enamel surfaces, these agents were unable to reverse the enamel subsurface demineralization.

Influence of skin cold sensation threshold in the occurrence of dental sensitivity during dental bleaching: a placebo controlled clinical trial

Abstract Objective This study verified the occurrence of dental sensitivity in patients submitted to a 35% hydrogen peroxide based product (Whiteness HP Maxx 35% - FGM), skin cold sensation threshold (SCST) and its influence on dental sensitivity. Material and Methods Sixty volunteers were divided into 4 groups (n = 15), according to SCST (low: GI and GIII, and high: GII and IV) and bleaching treatment (hydrogen peroxide: GI and GII, and placebo: GIII and GIV). SCST was determined in the inner forearm for 6 different times using a neurosensory analyzer, the TSA II (Medoc Advanced Medical Systems, Ramat Yishai, Northern District, Israel). Dental sensitivity measurements were performed 10 different times using a thermal stimulus and an intraoral device attached to TSA II, positioned in the buccal surface of the upper right central incisor. Spontaneous dental sensitivity was also determined using the Visual Analogue Scale (VAS). Data were submitted to Student's t-test and Pearson's Correlation Test (α=0.05). SCST remained the same during bleaching treatment. Results Distinct responses of dental sensitivity were found in patients with low and high SCST during the first and third bleaching session (p≤0.05). The teeth submitted to the bleaching treatment became more sensitive to cold than those treated with placebo. Moreover, data obtained with TSA and VAS presented moderate correlation. Conclusions Bleaching treatment increased dental sensitivity and skin cold sensation threshold might represent a determining factor in this occurrence, since low and high SCST patients had different responses to the thermal stimulus in the teeth.

Preemptive use of etodolac on tooth sensitivity after in-office bleaching: a randomized clinical trial

Abstract Purpose: This study determined the effectiveness of the preemptive administration of etodolac on risk and intensity of tooth sensitivity and the bleaching effect caused by in-office bleaching using 35% hydrogen peroxide. Material and methods: Fifty patients were selected for this tripleblind, randomized, crossover, and placebo-controlled clinical trial. Etodolac (400 mg) or placebo was administrated in a single-dose 1 hour prior to the bleaching procedure. The whitening treatment with 35% hydrogen peroxide was carried out in two sessions with a 7-day interval. Tooth sensitivity was assessed before, during, and 24 hours after the procedure using the analog visual scale and the verbal rating scale. Color alteration was assessed by a bleach guide scale, 7 days after each session. Relative risk of sensitivity was calculated and adjusted by session, while overall risk was compared by the McNemar's test. Data on the sensitivity level of both scales and color shade were subjected to Friedman, Wilcoxon, and Mann-Whitney tests, respectively (α=0.05). Results: The preemptive administration of etodolac did not affect the risk of tooth sensitivity and the level of sensitivity reported, regardless of the time of evaluation and scale used. The sequence of treatment allocation did not affect bleaching effectiveness, while the second session resulted in additional color modification. The preemptive administration of etodolac in a single dose 1 hour prior to in-office tooth bleaching did not alter tooth color, and the risk and intensity of tooth sensitivity reported by patients. Conclusion: A single-dose preemptive administration of 400 mg of etodolac did not affect either risk of tooth sensitivity or level of sensitivity reported by patients, during or after the in-office tooth bleaching procedure.

Neurosensory analysis of tooth sensitivity during at-home dental bleaching: a randomized clinical trial

Abstract Objective The objective of this study was to evaluate dental sensitivity using visual analogue scale, a Computerized Visual Analogue Scale (CoVAS) and a neurosensory analyzer (TSA II) during at-home bleaching with 10% carbamide peroxide, with and without potassium oxalate. Materials and Methods Power Bleaching 10% containing potassium oxalate was used on one maxillary hemi-arch of the 25 volunteers, and Opalescence 10% was used on the opposite hemi-arch. Bleaching agents were used daily for 3 weeks. Analysis was performed before treatment, 24 hours later, 7, 14, and 21 days after the start of the treatment, and 7 days after its conclusion. The spontaneous tooth sensitivity was evaluated using the visual analogue scale and the sensitivity caused by a continuous 0°C stimulus was analyzed using CoVAS. The cold sensation threshold was also analyzed using the TSA II. The temperatures obtained were statistically analyzed using ANOVA and Tukey's test (α=5%). Results The data obtained with the other methods were also analyzed. 24 hours, 7 and 14 days before the beginning of the treatment, over 20% of the teeth presented spontaneous sensitivity, the normal condition was restored after the end of the treatment. Regarding the cold sensation temperatures, both products sensitized the teeth (p<0.05) and no differences were detected between the products in each period (p>0.05). In addition, when they were compared using CoVAS, Power Bleaching caused the highest levels of sensitivity in all study periods, with the exception of the 14th day of treatment. Conclusion We concluded that the bleaching treatment sensitized the teeth and the product with potassium oxalate was not able to modulate tooth sensitivity.

Randomized clinical trial of the effect of NovaMin and CPP-ACPF in combination with dental bleaching

Abstract Objective This randomized, controlled, double-blind clinical study evaluated the effect of calcium sodium phosphosilicate (NovaMin) and casein phosphopeptide-amorphous calcium phosphate with fluoride (CPP-ACPF) on the prevention of post-operative sensitivity and on the effects of clinical bleaching treatment. Material and Methods Sixty volunteers were selected according to inclusion and exclusion criteria and were randomly assigned into three groups (n=20): CG (control group) patients, who were treated with 35% hydrogen peroxide; NOVAG (NovaMin group) patients, who were treated with 35% hydrogen peroxide followed by the application of NovaMin; and CPPG (CPP group) patients, who were treated with 35% hydrogen peroxide followed by the application of CPP-ACPF. Both bioactive agents were applied for five minutes. An evaporative stimulus associated with a modified visual scale was used to analyze sensitivity 24 hours after each bleaching session. The color evaluation was performed on the maxillary central incisors using a spectrophotometer. Associations between the intervention group, bleaching session, and reported sensitivity were tested using Chi-square partitioning. Results Color change values (ΔE) were analyzed using analysis of variance (ANOVA). The significance level used for both tests was 5%. In the intragroup assessment, the Friedman test showed that only the CPP-ACPF group showed no statistically significant difference (p<0.05) between baseline and first bleaching session. In the intergroup assessment, the Kruskal-Wallis test showed that the CPPG had less postoperative sensitivity after the first session, when compared to the other groups (p<0.05). Color change analysis (ΔE) showed a significant difference between the means obtained in the different bleaching sessions in all groups (p<0.05). Conclusions This study showed that the combination of CPP-ACPF with 35% hydrogen peroxide significantly reduced post-operative sensitivity in the first session, compared with the other evaluated treatments. The association of CPP-ACPF and NovaMin did not affect the color change induced by tooth bleaching.

Efeitos de protocolos excessivos associados a produtos clareadores caseiros sobre a microestrutura, a composição e as propriedades físicas do esmalte dentário humano / Effects of excessive protocols associated with home bleaching products on the microstructure, composition and physical properties of human tooth enamel

As técnicas clareadoras são consideradas seguras, simples e não invasivas. Assim, ganharam popularidade entre profissionais e pacientes. No entanto, o livre acesso do gel à estrutura dentária e o contato direto com a superfície do esmalte levantam dúvidas sobre seus reais impactos. Novas preocupações surgiram com os chamados produtos de bancada e a possibilidade de auto-aplicação, inclusive com consumo exagerado e/ou sem orientação e acompanhamento. Sendo assim, buscou-se avaliar, os efeitos de produtos clareadores caseiros sobre microestrutura, rugosidade, composição, nanodureza e módulo de elasticidade do esmalte dentário humano, em protocolos de uso normal ou excessivo. Amostras obtidas de 10 terceiros molares foram divididas em 4 grupos: grupo I ­ armazenamento em saliva artificial, grupo II ­ utilização de peróxido de carbamida (PC) 10%, grupo III ­ utilização de peróxido de hidrogênio (H2O2) 10%, grupo IV ­ utilização de tiras clareadoras (H2O2 10%). Cada dente forneceu quatro fragmentos de esmalte para cada um dos grupos. Foram realizadas aplicações diárias de acordo com a recomendação dos fabricantes, e foi adotada simulação de escovação duas vezes ao dia com escova elétrica. Todas as amostras foram armazenadas em saliva artificial e passaram por análises antes do início da terapia, após 4 e 8 semanas de intervenção. A escolha por técnicas não-destrutivas permitiu que cada amostra fosse seu próprio controle. Desse modo, a microscopia confocal por varredura a laser e microscopia de força atômica avaliaram alterações na microestrutura da superfície e foram coletados dados de rugosidade (Sa e Sq) para análise estatística. Os espécimes passaram por testes de nanoindentação para avaliação de nanodureza e módulo de elasticidade. Essas informações foram correlacionadas com as alterações de composição por microespectroscopia Raman. O clareamento com PC não apresentou alterações significativas nas amostras de esmalte, seguindo o padrão de comportamento daquelas escovadas e armazenadas em saliva artificial, tendo se mostrado segura. No entanto, os grupos que passaram por intervenção com H2O2 (III e IV) apresentaram modificações significativas em suas propriedades após 4 e 8 semanas de utilização. A alteração na superfície com aparência mais exposta foi associada a maior detecção de proteínas após as primeiras 4 semanas de utilização, especialmente para o grupo III. Após 8 semanas, a superfície apareceu mais suave, com perda do padrão prismático e queda no conteúdo orgânico, sugerindo uma perda de camadas superficiais desorganizadas. Do mesmo modo, o aumento dos valores de dureza e módulo de elasticidade para essas amostras pareceu derivar do efeito remineralizador da saliva e do papel positivo das proteínas mais expostas nas propriedades mecânicas permitindo maior deslizamento dos cristais e acomodação frente às cargas. Conclui-se que o uso de géis a base de H2O2 deve ser cauteloso, seguindo as recomendações profissionais e que são necessários testes in situ e in vivo para confirmar as tendências observadas.

The bleaching techniques are considered safe, simple and non-invasive and thus have gained popularity among professionals and patients. However, the free access of the gel to dental structures and the direct contact with the surface of the enamel, during the whole treatment raises doubts, about its possible impacts. Concerns were also raised about the emergence of so-called over-the-counter products and the possibility of self-application that could lead to excessive consumption and / or lack of guidance and monitoring. The aim of this study was to evaluate the effects of home bleaching products on the microstructure, roughness, composition, nanohardness and elastic modulus of human dental enamel in protocols of normal or excessive use. Samples were obtained from 10 third molars and divided into 4 groups: group I - storage in artificial saliva, group II - treatment with 10% carbamide peroxide, group III - treatment with 10% hydrogen peroxide, group IV - treatment with whitening strips (10% hydrogen peroxide). Each tooth provided four enamel fragments for treatment in each one of the groups. Daily applications were performed according to the manufacturers' recommendations, and a brushing simulation was used twice a day with an electric brush. All samples were stored in artificial saliva at the treatment intervals and were analyzed before the start of therapy, after 4 and 8 weeks of intervention. The choice by non-destructive techniques allowed each sample to be its own control. Qualitative analyzes of microstructure alteration were carried out using confocal laser scanning microscopy and atomic force microscopy. Roughness data (Sa and Sq) were also obtained for statistical analysis. Nanoindentation tests were used to determine changes in the nanohardness and elastic modulus. All of this information was correlated with composition changes by Raman micro-spectroscopy. Carbamide peroxide bleaching showed no significant changes in enamel samples, following the behavior pattern of those brushed and stored in artificial saliva, and therefore considered safe. However, the groups treated with hydrogen peroxide (III and IV) showed significant modifications in their properties after 4 and 8 weeks of treatment. The change in surface with more exposed appearance was associated with greater protein detection after the first month of treatment, especially for group III. After 8 weeks, the surface appeared smoother, with reduction of prismatic pattern and drop in organic content, suggesting a loss of disorganized mineral surface layers. Likewise, the increase in hardness and elastic modulus values for these samples seems to derive from the remineralizing effect of saliva and the positive role of the most exposed proteins in the mechanical properties, allowing greater slip of the crystals and accommodation with the loads. These changes may not reach clinically perceptible patterns but reinforce the importance of dentists' supervision and monitoring, since in-vivo the patient may be exposed to other challenges that may worsen the impacts. It is concluded that the use of hydrogen peroxide gels in bleaching therapies should be under professional supervision and that in situ and in vivo tests are required to confirm the observed trends.

Os pricipais efeitos colaterais do clareamento dentário: como amenizá-los / Tooth whitening: main T collateral effects and how to smooth them

Introdução: em busca de uma perfeita harmonia na forma e nas cores dos dentes, a dentística desenvolveu diversas alternativas para a melhoria da estética dentária, sendo que para o tratamento das alterações cromáticas, o procedimento mais utilizado atualmente é o clareamento dental. Objetivo: realizar uma revisão de literatura a cerca dos possíveis efeitos colaterais advindos das técnicas de clareamento dental e como minimizá-los. Material e Métodos: revisão de literatura por meio de busca bibliográfica nas bases de pesquisa online: PubMED, Medline, Lilacs, Scielo e Scopus, através do rastreio de artigos relevantes publicados entre o período de 2010 a 2016. Resultados: dentre os efeitos colaterais apresentados pelo clareamento dental, a sensibilidade durante e após o clareamento tem sido um dos efeitos adversos mais apontados na literatura, fato que pode ser resultado do aumento da permeabilidade do esmalte, com uma possível difusão do peróxido até a polpa, os tratamentos mais eficazes no controle da sensibilidade são: nitrato de potássio a 5%, fluoreto de sódio neutro a 2%, a terapia a laser e o uso de analgésicos e anti-inflamatórios. O gel clareador deve ser removido totalmente ao final do clareamento, porém se alguma quantidade do mesmo é deixada para trás, o paciente pode eventual deglutir, o que pode levar a irritação na mucosa gastrointestinal, dessa forma é importante que seja evitado o excesso de produto e de aplicações, atentando com a remoção cuidadosa dos excessos, para evitar sua ingestão e contato com tecidos moles. Conclusão: independentemente da técnica de clareamento a ser utilizada é necessária a supervisão e acompanhamento de um cirurgião-dentista, pois com o seu criterioso diagnóstico e adequado tratamento é que os resultados satisfatórios serão alcançados e os efeitos colaterais evitados e/ou minimizados. (AU)

Introduction: in order to achieve a perfect harmony in the shape and colors of the teeth, the dentistry has developed several alternatives for the improvement of dental aesthetics, and for the treatment of chromatic alterations, the most commonly used procedure is tooth whitening. Objective: to carry out a literature review about the possible side effects of dental bleaching techniques and how to minimize them. Material and Methods: a review of the literature was carried out through a bibliographic search in the following online databases: PubMED, Medline, Lilacs, Scielo and Scopus, through the screening of relevant articles published between 2010 and 2016. Results: among the side effects of tooth whitening, sensitivity during and after bleaching has been one of the most commonly reported adverse effects in the literature, a fact that may be a result of increased permeability of the enamel, with a possible diffusion of the peroxide to the pulp. The most effective treatments for sensitivity control are: 5% potassium nitrate, 2% neutral sodium fluoride, laser therapy and the use of analgesics and anti-inflammatories. The bleaching gel should be removed completely at the end of bleaching, but if any amount is left behind, the patient may eventually swallow, which may lead to irritation in the gastrointestinal mucosa, so it is important to avoid excess product And applications, with the careful removal of excess, to avoid its ingestion and contact with soft tissues. Conclusion: regardless of the technique of whitening to be used, it is necessary the supervision and follow-up of a dental surgeon, because with his careful diagnosis and appropriate treatment, satisfactory results will be achieved and the side effects avoided and/or minimized. (AU)