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

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

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

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

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.

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.

Effects of an Antioxidant on the Shear Bond Strengths of Orthodontic Brackets After Conventional and Laser-Assisted Extra-Coronal Bleaching / Efecto de un antioxidante sobre la fuerza de unión de brackets de ortodoncia posterior al blanqueamiento convencional y asistido por láser

RESUMEN El objetivo del presente estudio fue evaluar los efectos de la aplicación de un antioxidante sobre las fuerzas de unión (SBS) de brackets de ortodoncia posterior al blanqueamiento con peróxido de hidrógeno (HP). Metodología: Cincuenta premolares recién extraídos se dividieron aleatoriamente en tres grupos. El Grupo 1 se trató con 40% de HP (n=20), el grupo 2 con 40% de HP y se activó con láser de Nd: YAG (n=20) y un grupo de control (Grupo 3) no recibió tratamiento (n=10). Después del blanqueamiento, los Grupos 1 y 2 se dividieron en dos subgrupos (Grupo 1a, Grupo 1b, Grupo 2a y Grupo 2b). Las muestras en los subgrupos 1a y 2a (n=10) no recibieron ninguna aplicación del antioxidante. Se aplicó una solución de ascorbato de sodio al 10% a las muestras en los Grupos 1b y 2b (n=10). Luego, los brackets se adherieron a las superficies de esmalte de todos los grupos experimentales. Las muestras se sometieron a pruebas de SBS y los datos analizados estadisticamente. Resultados: La fuerza de unión de los grupos 1 y 2 fue significativamente más baja que el grupo de control (p <0.001); sin embargo, no se observaron diferencias estadísticamente significativas en SBS entre los grupos 1 y 2 (p>0.001). Las muestras tratadas con antioxidantes de los grupos 1b y 2b fueron significativamente mayores que las de los grupos 1a y 2a (p <0,001). Conclusion: La aplicación de 40% HP tuvo un efecto negativo en la resistencia de unión de los brackets. El uso de antioxidante durante 15 minutos mejoró significativamente la SBS.

ABSTRACT Purpose: The purpose of this study was to evaluate the effects of the application of antioxidant on the shear bond strengths (SBS) of orthodontic brackets bonded to human enamel after extra-coronal bleaching with hydrogen peroxide (HP). Materials and methods: Fifty freshly extracted premolars were randomly divided into three groups. One group (Group 1) was bleached with 40% HP (n=20), another group (Group 2) was bleached with 40% HP and activated with an Nd: YAG laser (n=20), and a control group (Group 3) received no treatment (n=10). After the bleaching procedure, Groups 1 and 2 were further divided into two subgroups (Group 1a, Group 1b, Group 2a, and Group 2b). Specimens in Groups 1a and 2a (n=10) received no antioxidant application. A 10% sodium ascorbate solution was applied to specimens in Groups 1b and 2b (n=10). The brackets were then bonded with light-cure adhesive paste to the enamel surfaces of all experimental groups. Specimens were subjected to SBS tests for debonding. Results: The SBS of brackets bonded in Groups 1 and 2 were significantly lower than those of brackets bonded to the control group (p<0.001); however, no statistically significant differences in SBS were noted in Groups 1 and 2 (p>0.001). The antioxidant-treated SBS of brackets in Groups 1b and 2b were significantly higher than those of Groups 1a and 2a (p<0.001). Conclusions: The application of 40% HP had a negative effect on the bond strength. The use of antioxidant for 15 min resulted in the reversal of failed bond strength.

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.

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.

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.

Post-bleaching sensitivity in patients with sickle cell disease / Sensibilidade dentária pós-clareamento em pacientes com doença falciforme

Sickle cell disease (SCD) is a monogenic disease that affectsmillions of people worldwide. This study analyzed theeffectiveness of bleaching and tooth sensitivity after in-officebleaching in patients with SCD. Forty volunteers wererandomly assigned to four groups of 10 patients each (five withthe SCD and five healthy controls) and treated using in-officebleaching with 35% hydrogen peroxide and different lightactivation protocols. No statistically significant difference wasobserved with relation to presence of tooth sensitivity, with orwithout use of a source of light for peroxide activation, and allbleaching therapies were effective, regardless of the techniqueemployed and the presence/absence of sickle cell disease. Thedata showed that in-office dental bleaching is a viablealternative for improvement of oral esthetics for patients with SCD.

A doença falciforme (DF) é a doença monogênica e afetamilhões de pessoas em todo o mundo. Este estudo analisou aeficácia do clareamento e a presença de sensibilidadedentinária após clareamento dental em portadores de DF.Quarenta voluntários distribuídos aleatoriamente em quatrogrupos com diferentes fontes de luz foram submetidos à técnicade clareamento em consultório, utilizando peróxido dehidrogênio a 35%. Não foram encontradas diferenças estatisti -ca mente significativas em relação á presença de sensibilidade,com ou sem a utilização de uma fonte de luz para acelerar aativação do peróxido e todos os clareamentos foram efetivos,independentemente da técnica utilizada e da presença/ausênciade DF. Os dados mostraram que o clareamento dental em consultório, utilizando peróxido de hidrogênio a 35% é uma alternativa viável para melhoria da estética em pacientes com DF.

Effect of bleaching agents containing fluoride or calcium on enamel microhardness, roughness and permeability

To evaluate the effect of different in-office bleaching agents on the permeability, roughness and surface microhardness of human enamel. Methods: For evaluation of roughness and microhardness, 40 hemi-faces of 20 premolars were subjected to initial roughness (Ra parameter) and microhardness (VHN) measurements. Thirty-two premolar's crowns were used for permeability test. Then, all specimens were randomly divided into four groups: C - without bleaching (control), HP35 - bleaching with 35% hydrogen peroxide (HP), HPF38 - 38% HP+fluoride, HPC35 - 35% HP+calcium. Final roughness (FR) and microhardness (FM) measurements were evaluated. For permeability, the 32 crowns were immersed in 1% sodium hypochlorite (20 min) and silver nitrate solutions (2 h) and subjected to developing solution under fluorescent light (16 h). Three sections from the crowns were analyzed in light microscope (100x) to evaluate the scores of permeability: Score 0 - no tracer agent penetration; Score 1 - less than half the thickness of enamel penetration; Score 2 - tracer agent reaching half the enamel thickness; Score 3 - entire enamel depth penetration, without reaching dentin and Score 4 - tracer agent reaching dentin. For roughness and microhardness evaluation were used one-way ANOVA and Dunnet post-test for independent samples, and t test for paired samples. For permeability, the data were analyzed by Kruskal Wallis and Dunn tests. Results: A significantly higher permeability and surface roughness were observed in groups HP35, HPF38 and HPC35 compared to the C group, as well as decreased microhardness (p<0.05). Conclusions: All bleaching agents increased permeability and surface roughness, and decreased microhardness of human enamel; thus, the addition of fluoride or calcium was not beneficial...

Acción de los agentes blanqueadores sobre materiales de restauración / Action of bleaching agents on restorative materials

El propósito del trabajo será analizar comparativamente los diversos efectos que producen sobre las restauraciones dentales agentes blanqueadores.El objetivo será valorar los cambios que experimentan en la superficie los materiales de restauración, sometidos a la acción de un agente blanqueador. La metodología utilizada será visualización microscópica electrónica de barrido ambiental. Los resultados obtenidos tendrán transferencia relevante a Insti-tuciones formadoras de recursos humanos en Salud Bucal, al campo profesional odontológico y a empresas o fabricantes para el mejoramiento de su producto...

Dental bleaching agents with calcium and their effects on enamel microhardness and morphology

Aim: To evaluate enamel microhardness and morphology after bleaching with hydrogen peroxide containing calcium in different concentrations. Methods: One hundred specimens of human teeth were ground and polished and had the initial microhardness evaluated. The specimens were randomly assigned into five groups (n=20): Group 1 - Control group (no treatment); Group 2 - Home Peroxide 6% (without calcium); Group 3 - Home Peroxide 7.5% (without calcium); Group 4 - White Class 6% (with calcium); Group 5 - White Class 7.5% (with calcium). For each group, the bleaching was performed according to the manufacturer's specifications. The specimens were bleached once a day for 5 days and subjected to pH cycling. Microhardness and scanning electron microscopy (SEM) analysis were performed before and after bleaching. Results: The results showed that groups submitted to bleaching treatment presented hardness loss compared to the control group. The group of 7.5% hydrogen peroxide with calcium showed a lower percentage of hardness loss in relation to other groups. Conclusion: Calcium in association with a higher hydrogen peroxide concentration may decrease microhardness changes on enamel.

Influência do perborato de sódio na desadaptação marginal de tampões cervicais confeccionados com diferentes materiais / Influence of sodium perborate on marginal misfit in cervical barrier made by different materials

Frente aos efeitos deletérios da reabsorção cervical externa, é de grande importância a confecção do tampão cervical quando do clareamento de dentes despolpados. Objetivo: este estudo avaliou a influência do perborato de sódio (PS) e o número de aplicações na desadaptação marginal do tampão cervical. Metodologia: Vinte e quatro pré-molares inferiores foram divididos em três grupos (n=8), de acordo com o material utilizado na confecção do tampão: Cimento de Ionômero de Vidro (CIV), Bioplic (BP) e Agregado de Trióxido Mineral branco (MTA B). Após a aplicação dos materiais, os espécimes foram aplainados e registrados por uma câmera fotográfica acoplada ao Esteromicroscópio. O PS diluído em soro fisiológico foi acomodado sobre os tampões e em seguida selados por 15 dias. Em seguida, o PS foi removido e novas imagens realizadas no Estereomicroscópio. Este ciclo foi repetido, determinando três períodos de avaliação. A desadaptação marginal foi calculada por meio do Software Image J, e os dados submetidos ao teste estatístico de Kruskal-wallis com post-hoc de Dunn para comparação intergrupos (α menor ou igual a 0,05), e teste de Friedman para comparação intragrupos (α menor ou igual a 0,05). Resultados: Verificou-se um aumento significativo na desadaptação marginal do BP e CIV entre os períodos controle e 2ª sessão. Na comparação intergrupos, o MTA B apresentou maior desadaptação quando comparado ao BP em todos os períodos. Conclusão: o PS foi capaz de aumentar a desadaptação marginal de dois materiais após 30 dias, e o MTA B seria o material menos indicado para confecção do tampão cervical...

Due to the deleterious effects of the external cervical resorption, it is extremely important the use of an appropriate cervical barrier in non-vital bleaching. Objective: this study evaluated the influence of sodium perborate (SP) and the number of its application on cervical barrier marginal misfit. Methods: twenty- four human premolars were divided into 3 groups (n=8) according to the material used in manufacture of barrier: Glass Ionomer cement (GIC), Bioplic (BP) and white Mineral Trioxide aggregate (W MTA). After the application of the materials, specimens were planed and registered with a camera mounted in a stereomicroscope. SP diluted in saline was accommodated on the barrier and then sealed for 15 days. Afterwards SP was removed and images were again obtained with stereomicroscope. This cycle was repeated once more, determine three periods of evaluation. Marginal misfit was obtained through Image J software, and the data was subjected to two-way analysis of variance, followed by Tukey post-hoc test (α or less 0,05). Results: there was a significant increase in the marginal misfit of BP and CIV between periods control and 2nd session. In the intergroup comparison, the MTA B showed larger marginal misfit when compared to BP in all periods. Conclusion: the PS was able to increase marginal misfit of 2 materials after 30 days, and the MTA B would be less suitable for making the cervical barrier...

In-office bleaching effects on the pulp flow and tooth sensitivity – case series

Laser Doppler flowmetry (LDF) is a noninvasive method capable of evaluating variations in pulp blood flow (PBF) and pulp vitality. This method has thus far not been used to assess changes in blood flow after in-office bleaching. The aim of this case series report was to measure changes in PBF by LDF in the upper central incisor of three patients submitted to in-office bleaching. The buccal surfaces of the upper arch were bleached with a single session of 35% hydrogen peroxide gel with three 15-min applications. The color was recorded using a value-oriented Vita shade guide before in-office bleaching and one week after the procedure. The tooth sensitivity (TS) in a verbal scale was reported, and PBF was assessed by LDF before, immediately, and one week after the bleaching session. The lower arch was submitted to dental bleaching but not used for data assessment. A whitening degree of 3 to 4 shade guide units was detected. All participants experienced moderate to considerable TS after the procedure. The PBF readings reduced 20% to 40% immediately after bleaching. One week post-bleaching, TS and PBF were shown to be equal to baseline values. A reversible decrease of PBF was detected immediately after bleaching, which recovered to the baseline values or showed a slight increase sooner than one week post-bleaching. The LDF method allows detection of pulp blood changes in teeth submitted to in-office bleaching, but further studies are still required.

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.

Avaliação da temperatura dental in vitro em procedimentos de clareamento dental de consultório / Evaluation of the dental temperature in vitro in tooth whitening procedures at the dental office

Este trabalho teve por objetivo avaliar a variação de temperatura na face vestibular e intra câmara pulpar gerada por diferentes protocolos de clareamento em consultório. Um canino superior humano foi seccionado abaixo da junção amelocementária e teve o interior de sua câmara pulpar ampliado para receber uma pasta condutora térmica e o sensor do termômetro digital termopar tipo K. A aferição da temperatura na face vestibular foi realizada com termômetro digital infravermelho com Mira Laser. Os protocolos de clareamento no dente selecionado foram distribuídos em doze grupos experimentais, variando-se a luz de ativação: luz híbrida LED e laser diodo (UltraBlue© IV–DMC), luz halógena (Spectrum Curing Light©, Dentsply Caulk) e ultravioleta (Zoom! Lamp© – Discus Dental), e os tratamentos: sem gel clareador, Lase Peroxide© (DMC), Whiteness HP Maxx© (FGM) e Whiteness HP© (FGM). Os resultados foram submetidos … análise de variância a 2 critérios (ANOVA) e teste de tukey (p≤0,05). As maiores elevações de temperatura (5øC) no interior da câmara pulpar foram observadas nos grupos ativados com a lâmpada ultravioleta sem a utilização de gel e comWhiteness HP Maxx. A luz híbrida apresentou menor aumento de temperatura (de 1,7 a 2øC). Em relação à temperatura externa, a Zoom! Lamp também induziu o maior aumento, estatisticamente significante em relação aos demais. Tanto o gel clareador quanto a ativação por luz foram relevantes para o aumento de temperatura no interior da câmara pulpar. Na face vestibular o aumento de temperatura deu-se pela ativação por luz, independente do gel utilizado.

This study aimed to evaluate the temperature variation in the vestibular surface of teeth and inside their pulp chamber generated by different protocols in office whitening. A human upper canine was sectioned below the enamel-cement junction and had the interior of its chamber enlarged to receive a thermally conductive paste and the sensor of type K digital thermometer. The temperature measurement was performed on the vestibular surface with infrared digital thermometer with laser-sights. The protocols in tooth whitening selected were distributed in twelve experimental groups, varying the light activation: light hybrid LED and laser diode (UltraBlue IV© - DMC), halogen light (Spectrum Curing Light©, Dentsply Caulk) and ultraviolet (Zoom! Lamp© - Discus Dental), and treatments: no bleaching gel, Lase Peroxide© (DMC), Whiteness HP Maxx© (FGM), and Whiteness HP© (FGM). Results were subjected to variance analysis 2 way (ANOVA) and Tukey test (p≤0.05). The highest elevations of temperature (5øC) inside the pulp chamber were observed in the groups activated with ultraviolet light without the use of gel and Whiteness HP Maxx©. The light hybrid showed a smaller increase in temperature (from 1.7 to 2øC). On the facial surface, the Zoom! Lamp also induced the largest increase statistically significant in relation to others. Both the bleaching gel and light activation were relevant to the temperature increase inside the pulp chamber. In vestibular surface temperature increase occurred by light activation, regardless the used gel.