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.

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.

Genotoxic potential of 10% and 16% Carbamide Peroxide in dental bleaching

Dental bleaching has become one of the most frequently requested esthetic treatments in dental offices. Despite the high clinical success observed with this procedure, some adverse effects have been reported, including a potential for developing premalignant lesions, root resorption and tooth sensitivity, especially when misused. The aim of this study was to evaluate the genotoxic response using a micronucleus (MN) assay, after the application of two concentrations of carbamide peroxide. Thirty-seven patients were divided into two groups and randomly received either a 10% carbamide peroxide (CP) (19) or a 16% carbamide peroxide (18) concentration for 21 days in individual dental trays. Gingival margin cells were collected immediately before the first use (baseline), and then 15 and 45 days after baseline. The cells were placed on a histological slide, stained by the Feulgen technique, and evaluated by an experienced blinded examiner. One thousand cells per slide were counted, and the MN rate was determined. The two groups were analyzed by the Wilcoxon rank-sum test and the Kruskal-Wallis equality-of-populations rank test. A slight increase in MN was observed for both groups, in comparison with the baseline, at 15 days. However, no difference was observed between the two groups (10% and 16%), at either 15 or 45 days (p = 0.90). When bleaching is not prolonged or not performed very frequently, bleaching agents containing carbamide peroxide alone will not cause mutagenic stress on gingival epithelial cells.

Bochechos com água oxigenada são carcinogênicos e indicados na internet: implicações ortodônticas e fundamentos / Mouthwash with hydrogen peroxide are carcinogenic and displayed on the internet: orthodontic implications and foundations

Em breve, teremos trabalhos sobre os efeitos do peróxido de hidrogênio na união dos braquetes aderidos ao esmalte, sobre os elásticos intermaxilares, os metais e cerâmicas dos próprios braquetes, na fixação da contenção e outras implicações práticas clínicas dos bochechos com água oxigenada, livremente indicados irresponsavelmente via internet, por pessoas despreparadas. Esses bochechos com água oxigenada pretensamente visam a antissepsia e a clareação dentária, estando “indicados” para uso diário e/ou semanal; no entanto, esses bochechos têm efeitos cocarcinogênicos na mucosa bucal e demais mucosas do trato gastrintestinal. Nesse artigo, procuraremos informar e dar fundamentos para que os profissionais da Odontologia e auxiliares possam embasar suas reflexões, opiniões e condutas relacionadas ao tema “uso indiscriminado e livre de peróxido de hidrogênio na boca sobre os dentes e mucosa bucal”.

Mineral Loss and Morphological Changes in Dental Enamel Induced by a 16% Carbamide Peroxide Bleaching Gel

The aim of this study was to compare the effect of a 16% carbamide peroxide (CP) gel and a 10% CP gel on mineralized enamel content and morphology. Enamel blocks from bovine incisors were subjected to a 14-day treatment (8 h/day) with 10% or 16% CP gels. Knoop microhardness was evaluated before bleaching and at 1, 7 or 14 days after this treatment (50 g/15 s). Mineral content (energy-dispersive x-ray spectroscopy), surface roughness and topography (atomic force microscopy) were evaluated at the 14-day period. Data were analyzed statistically by two-way ANOVA and Tukey's test (α=0.05). Significant microhardness reduction was observed at the 7 th and 14 th days for 10% CP gel, and for all bleaching times for 16% CP gel (p<0.05). At the 14-day period, a significant decrease in Ca and P content, increase on surface roughness (p<0.05) as well as on picks and valleys distance were observed when both bleaching gels were used. These enamel alterations were more intense for 16% CP gel. It was concluded that both CP-based gels promoted loss of mineral structure from enamel, resulting in a rough and porous surface. However, 16% CP gel caused the most intense adverse effects on enamel.

O objetivo do presente estudo foi comparar o efeito de um gel com 16% de peróxido de carbamida (PC) sobre a estrutura mineral e morfologia do esmalte dental com os efeitos de um gel com 10% de PC. Blocos de esmalte provenientes de incisivos bovinos foram submetidos a 14 dias de tratamento (8 h/dia) com géis com 10 ou 16% de PC. A microdureza Knoop foi avaliada antes do clareamento e 1, 7 e 14 dias pós-tratamento (50 g/15 s). O conteúdo mineral (EDX), rugosidade de superfície e topografia (MFA) foram avaliados no período de 14 dias (ANOVA a dois critérios e teste de Tukey; α=0,05). Redução significante na microdureza foi observada nos períodos de 7 e 14 dias para o gel com 10% de PC, e em todos os períodos para o gel com 16% de PC (p<0,05). No período de 14 dias, uma diminuição significante no conteúdo de Ca e P, aumento na rugosidade de superfície (p<0,05), bem como na distância entre picos e vales foram observados para ambos os agentes clareadores usados. Estas alterações foram mais intensas para o gel com 16% de PC. Pôde-se concluir que ambos os géis à base de PC promoveram perda de estrutura mineral do esmalte, resultando em superfície mais rugosa e porosa. Porém, o gel com 16% de PC causou efeitos adversos mais intensos no esmalte dental.

Efeito do peróxido de carbamida e do flúor neutro sobre a superfície do esmalte / Effect of carbamide peroxide and neutral fluoride on enamel surface

This study evaluated the effect of a 10% carbamide peroxide gel on enamel surface and the remineralizing capacity of neutral fluoride applied either during or after bleaching treatment. Sixteen fragments were obtained from four extracted human teeth (incisors and molars) and assigned to four groups. Group I served as the control and groups II, III and IV underwent daily 8-hour carbamide peroxide bleaching treatment for 2 weeks. Additionally, group III was treated with 2% neutral fluoride gel for 4 minutes/day, and group IV received one single application of fluoride gel at the end of the 2-week bleaching treatment. Specimens were examined under scanning electron microscopy (SEM). Micrograph analysis showed that the bleaching gel caused changes to the enamel surface and that the application of neutral fluoride gel during or after treatment did not completely reverse the changes caused by bleaching. Carbamide peroxide increased enamel porosity. Application of neutral fluoride gel during or after the treatment did not produce any significant decrease in enamel porosity. Total enamel recovery seems to be more strongly associated with the buffering properties of saliva than with the use of different fluoride application protocols.

Este estudo avaliou o efeito de um gel de peróxido de carbamida a 10% sobre a superfície do esmalte e a capacidade de remineralização da aplicação de flúor neutro durante e após o tratamento de clareamento. Dezesseis fragmentos foram obtidos de quatro dentes humanos extraídos (incisivos e molares) e distribuídos em quatro grupos. O grupo I serviu como controle, e os grupos II, III e IV foram submetidos a 8 horas diárias de clareamento com peróxido de carbamida durante 2 semanas. O grupo III foi tratado com gel de flúor neutro a 2% por 4 minutos diariamente, e o grupo IV recebeu uma aplicação de flúor ao final de 2 semanas de tratamento clareador. Os espécimes foram examinados sob microscopia eletrônica de varredura (MEV). A análise das fotomicrografias mostrou que o gel clareador causou alterações na superfície do esmalte e que a aplicação do gel de flúor neutro durante ou após o tratamento clareador não reverteu completamente as alterações causadas pelo procedimento clareador. O peróxido de carbamida aumentou a porosidade do esmalte. A aplicação de gel de flúor neutro durante ou depois do tratamento não produziu um aumento significativo na porosidade do esmalte. A recuperação total do esmalte parece estar mais associada com a capacidade tampão da saliva do que com o uso de diferentes protocolos de aplicação de flúor.

In vitro analysis of morphology of human enamel submitted to excessive use of external bleaching agents / Análisis in vitro de la morfología del esmalte humano sometido a un uso excesivo de agentes blanqueadores externos

The aim of this study was to evaluate the effects of external bleaching agents on morphology of human enamel after excessive homemade dental bleaching. 20 intact human third molars were submitted to mesio-distal crosscut and embedded in polystyrene resin. The specimens were submitted to finish and a half of enamel surface of each specimen was covered with cosmetic varnish, meaning control group (G0). The specimens were randomly divided into four groups (n=10): G1 ­ 1 bleaching session by 16 percent carbamide peroxide; G2 ­ 3 bleaching sessions by 16 percent carbamide peroxide; G3 1 bleaching session by 22 percent carbamide peroxide; G4 3 bleaching sessions by 22 percent carbamide peroxide. Each session lasted 8 hours a day, during two weeks, with 45 days of interval between sessions. In this period, the specimens were kept in artificial saliva at 37°C. The specimens were observed by scanning electron microscopy and the results showed depression areas, irregularities, erosion, and enamel prisms exposition, which was more evident in G4. It can be concluded that the excess of bleaching produced many alterations on enamel surface, mainly when was used carbamide peroxide in higher concentration.

El objetivo de este estudio fue evaluar los efectos en la morfología externa del esmalte humano al utilizar excesivamente agentes blanqueadores dentales de uso casero. Se cortaron 20 intactos terceros molares humanos en sentido mesiodistal, luego fueron sumergidas las porciones radiculares en resina de poliestireno. Las muestras fueron pulidas, cubriendo la mitad de la superficie del esmalte con barniz cosmético, representando así al grupo control (G0). Las muestras fueron distribuidas aleatoriamente en cuatro grupos (n=10): G1-Una sesión de blanqueamiento con peróxido de carbamida al 16 por ciento, G2. Tres sesiones de blanqueamiento con peróxido de carbamida al 16 por ciento, G3-Una sesión de blanqueamiento con peróxido de carbamida al 22 por ciento, G4- Tres sesiones de blanqueamiento con peróxido de carbamida al 22 por ciento. Cada sesión tuvo una duración de 8 horas diarias durante dos semanas con 45 días de intervalo entre sesiones. Durante ese periodo las muestras fueron mantenidas en saliva artificial a 37°C. Las muestras fueron observadas al microscopio electrónico de barrido, mostrando aéreas de depresión, irregularidades, erosiones y exposición de prismas del esmalte. Esto fue más evidente en G4. Se puede concluir que el exceso de blanqueamiento producido muchas alteraciones en la superficie del esmalte, sobre todo cuando se utilizó peróxido de carbamida en alta concentración.

Avaliação clínica da eficácia do clareamento dental pela técnica caseira utilizando moldeiras com e sem alívio / Clinical evaluation of home bleaching using trays constructed with or without reservoirs

O objetivo desse trabalho foi avaliar clinicamente a eficácia do clareamento dental com peróxido de carbamida a 16%, utilizando a técnica caseira com e sem alívio na moldeira, e analisar a hipersensibilidade dentinária provocada pelo procedimento clareador. Esse estudo randomizado, duplo-cego e com desenho experimental de boca dividida avaliou onze pacientes, sendo os dentes 11 e 21 avaliados previamente por dois examinadores calibrados (Kappa 0,75). A hemi-arcada direita recebeu alívio no modelo de gesso para a confecção da moldeira, enquanto a esquerda não recebeu. O clareamento foi realizado durante 2 semanas, 6 horas por dia. Logo após esse período, os dentes 11 e 21 foram reavaliados pelos mesmos examinadores e os pacientes foram questionados sobre a hipersensibilidade. Os dados foram analisados pelo teste exato de Fisher (p>0,05) e mostraram que não houve diferença significativa no clareamento entre as técnicas com e sem alívio. Todos os pacientes relataram hipersensibilidade dentinária durante o clareamento. Concluiu-se que a técnica caseira foi eficaz no clareamento dental, independentemente da presença do alívio na moldeira. O clareamento provocou hipersensibilidade dentinária em todos os casos.

The aim of this study was to evaluate the clinical performance of 16% carbamide peroxide home vital bleaching, using trays constructed with or without reservoirs, and analyze thepostoperative hypersensitivity. This was a randomized, double-blind and split-mouth study. Two examinators evaluated 11 and 21 teeth from eleven patients (Kappa 0,75). Right side of upper stone models received reservoirs before trays were constructed, left side didn’t. Home bleaching was performed through two weeks, 6 hours-day. After this time, 11 and 21 teeth was evaluatedagain by the same examinators. Patients were asked about ostoperative hypersensitivity. Data were statistically analyzed by Fisher’s exact test (p>0,05), and didn’t show any statistically significant difference between trays with or without reservoirs. All patients related postoperative hypersensitivity during bleaching time. Home bleaching technique was effective on dental bleaching, with or without reservoirs on the trays. Home bleaching promoted postoperative hypersensitivityin all cases.

Over-the-counter whitening agents: a concise review

Tooth discoloration is commonly found in the dental clinic and tooth bleaching has been considered the preferred esthetic alternative, being more conservative, safe and with predictable results. Supervised home-use of 10 percent Carbamide Peroxide (CP) bleaching with custom-trays is the most common bleaching procedure dispensed by dentists to their patients. The good results obtained with this technique stimulated the flourishing of new products and techniques. Over-the-counter (OTC) bleaching products appeared as a low-cost alternative to bleach discolored teeth without dentist supervision. Different OTC products are available in supermarkets, drug stores or on the Internet, including rinses, paint-on brushes, toothpastes, chewing guns, dental floss, and whitening strips. There is lack of clinical evidence regarding the safety and effectiveness of these products, being most of the studies supported by the manufacturers'. Basically, toothpastes, chewing gums, and dental floss are removal agents of superficial stains. Rinses and paint-on brushes with low levels of hydrogen peroxide have some whitening effect, but without clinical relevance. Strips present similar esthetic results and side-effects, compared to bleaching with 10 percent CP using trays; however, the studies have financial support from the manufacturers and were based on short term evaluations. Legislation varies widely in different countries regarding OTC dental bleaching. Concerns have appeared due to the potential abusive use of these self-medication agents, especially in young patients, with potential harmful results. Dentists should be acquainted with this kind of products to be able to inform their patients. In conclusion, there is a need for independent clinical trials to provide sufficient evidence regarding the use of OTC bleaching products.

Effect of 10 percent carbamide peroxide bleaching on sound and artificial enamel carious lesions

This study evaluated the effect of 10 percent carbamide peroxide (CP) bleaching on Knoop surface microhardness (KHN) and morphology of sound enamel and enamel with early artificial caries lesions (CL) after pH-cycling model (pHcm). Human dental enamel blocks were randomly divided into 6 groups (n=10): 1 - sound enamel bleached (S) with CP (Rembrandt/Den-Mat); 2 - S and submitted to pHcm; 3 - CL bleached with CP; 4 - CL stored in artificial saliva and submitted to pHcm; 5 - CL treated with placebo gel and submitted to pHcm; 6 - CL bleached with CP and submitted to pHcm. Enamel blocks with known initial KHN values were demineralized (groups 3 to 6) and submitted to 12 day pHcm (groups 2, 4, 5 and 6). After demineralization and treatments, KHN was determined and the specimens were examined using scanning electron microscopy (SEM). Data were analyzed statistically by ANOVA and Tukey's test at 5 percent significance level. The results showed that among CL groups (3 to 6) only the group 3 presented remineralization after treatments. S groups (1 and 2) showed higher KHN and presented less formation of porosities on enamel surface than CL groups after treatments. In conclusion, bleaching procedures on enamel with CL did not exacerbate the demineralization, but should be indicated with caution.

Este estudo analisou o efeito do peróxido de carbamida a 10 por cento (PC) na microdureza Knoop de superfície (KHN) e morfologia do esmalte hígido e com lesões iniciais de cárie artificial (EC), após modelo de ciclagem de pH (cpH). Blocos de esmalte dental humano foram divididos aleatoriamente em 6 grupos (n=10): 1- esmalte hígido clareado (EHC) com PC (Rembrandt/Den-Mat); 2- EHC e submetido a cpH; 3- EC clareado com PC; 4- EC armazenado em saliva artificial e submetido a cpH; 5- EC tratado com gel placebo e submetido a cpH; 6- EC clareado com PC e submetido a cpH. Blocos de esmalte com a KHN conhecida eram desmineralizados (grupos 3 a 6) e submetidos a cpH (grupos 2, 4, 5 e 6). KHN foi determinada após a desmineralização e os tratamentos. Os espécimes foram examinados através de Microscopia Eletrônica de Varredura (MEV). Os dados foram analisados através de ANOVA e teste de Tukey (p<0,05). Os resultados indicaram que entre os grupos com EC (3 a 6) somente o grupo 3 apresentou remineralização após os tratamentos. Os grupos EHC (1 e 2) mostraram maior KHN e menor formação porosidades quando comparados aos grupos EC após os tratamentos. Os procedimentos clareadores no esmalte com lesão de cárie não exacerbaram a desmineralização, entretanto precisam ser indicados com cautela.

Comparação da superfície do esmalte antes e após clareamento com dois diferentes agentes: estudo clínico / Comparision of enamel surface before and after bleaching with twodifferent agents: clinical study

O objetivo deste estudo foi comparar a superfície do esmalte antes e após clareamento com dois diferentes agentes. Vinte pacientes foram selecionados e divididos em dois grupos: Grupo 1 - tratados através da técnica de clareamento vital caseiro utilizando peróxido de carbamida a10% (Whiteness Perfect) e Grupo 2 - tratados através da técnica vital de consultório utilizando peróxido de hidrogênio a 35% (Whiteness HP). Réplicas em resina epóxi dos incisivos centrais de todos os pacientes foram obtidas antes, imediatamente após e trinta dias depois da conclusão dos tratamentos. Todas as réplicas foram fotografadas em microscópio eletrônico de varredura e um examinador experiente e cego as classificou nos seguintes escores: 1- superfície sem alteração 2-superfície com alteração. O estudo demonstrou que a realização do clareamento com os dois diferentes agentes causa efeitos sobre a superfície do esmalte, mas que esses são parcialmente revertidos em 30 dias.

The purpose of this study was to compare of enamel surface before and after bleaching with two different agents. Twenty subjects were selected and divided in two groups: Group 1- treated with the night guard vital bleaching using 10% carbamide peroxide (Whiteness Perfect) and Group2- treated with the in-offi ce technique using 35% hydrogen peroxide (Whiteness HP). Epoxi resin replicas obtained from the maxillary central incisors, before, immediately after and thirty days after the bleaching procedure. All replicas were hotography in scanning electron microscopy andexamined for one expert and blind examiner taken in scores: 1- surface without alteration 2- surface with alteration. This study demonstrated that bleaching treatment using both agents causes effect on namel surface, but these are partially reverted in thirty days.

[Evaluation of the effect of 16% carbamide peroxide gel [Nite White] on mercury release from Iranian and foreign spherical and admixed amalgams by cold vapor atomic absorption method]

Nowadays, esthetic dentistry has become an important part of modern dentistry. Bleaching is considered as a conservative, safe and effective way for treatment of discolored teeth. Although bleaching is commonly used on anterior teeth, the bleaching gel may come into contact with patient's former amalgam restorations and result in corrosive effects, dissolution of amalgam phases and increasing release of mercury. Mercury released from dental amalgam during mouthguard bleaching can be absorbed and increase the total mercury body burden. The aim of this study was to determine the amount of mercury released from Iranian and foreign brands of amalgams with spherical and admixed particles, polished and unpolished, after 16% carbamide peroxide gel application. This experimental in vitro study was performed on 256 Iranian and foreign amalgam samples with spherical and admixed particles. The provided samples were put in distilled water and classified according to the type of amalgam, shape of particles and quality of surface polishing. The test samples were placed in Nite White 16% carbamide peroxide gel and control samples were put in phosphate buffer [Ph=6.5] for 14 and 28 hours. The amount of released mercury was calculated using AVA-440 Mercury Analysis System [Thermo Jarrell Ash model SH/229] with cold-vapor atomic absorption. Data were analyzed using t-test, four way and three way ANOVA tests with P<0.05 as the level of significance. 16% Nite White carbamide peroxide gel caused a significant increase in amount of mercury released from amalgams in all groups [P<0.05]. Mercury release from Iranian amalgam was higher than that from the foreign brands [P<0.05]. There was no significant difference in mercury released from spherical and admixed amalgams [P>0.05]. The amount of mercury released from Iranian and foreign amalgams was time dependent [P<0.05]. Furthermore, the amount of mercury released from unpolished amalgams was higher than polished ones [P<0.05]. the present study indicated that exposure of amalgam to 16% Nite White carbamide peroxide gel causes a significant increase in mercury release from the amalgam which is significantly influenced by the brand, exposure time and surface, polishing

Avaliação clínica da efetividade do peróxido de carbamida em diferentes concentrações para clareamento de dentes vitalizados naturalmente escurecidos / Clinical evaluation of the effectiveness of different concentrations of carbamide peroxide used on vital bleaching teeth

A técnica supervisionada de clareamento dental representa uma alternativa para reversão química do escurecimento dentário, sendo realizada com a aplicação, sobre os dentes, do peróxido de carbamida, em concentrações variadas, com o auxílio de moldeiras personalizadas. Este trabalho avaliou clinicamente a efetividade e segurança de uso do peróxido de carbamida em duas concentrações, quando aplicados com moldeiras individualizadas confeccionadas com ou sem alívio na face vestibular. Foram selecionados 26 pacientes, que se submeteram ao clareamento dental com peróxido de carbamida a 16% (arco suprior) e a 10% (arco inferior). As moldeiras foram confeccionadas com alívio apenas nos hemi-arcos esquerdos (superior e inferior) e os pacientes foram divididos aleatoriamente em dois subgrupos, onde o primeiro realizou o tratamento por 02 horas/dia e o segundo por 04 horas/dia. Os resultados do estudo evidenciaram que não houve diferenças significativas, após 14 dias de tratamento clareador, entre os grupos estudados. Entretanto, foi possível observar que a concentração de 16% empregada por horas/dia foi responsável por uma maior incidência de sensibilidade trans-operatória, assim como de leve irritação gengival. Concluindo-se que: as concentrações de peróxido de carbamida 10% e 165 foram efetivadas para o clareamento de dentes naturalmente escurecidos quando usadas, por um período de 14 dias, em moldeiras com ou sem alívio vestibular; e que quanto maior a concentração e o tempo de exposição ao agente clareador maior a possibilidade dentária trans-operatória e irritação gengival.

Home tooth bleaching represents an alternative to chemical reversal of natural teeth darkening, through the application of the carbamida peroxide in varied concentrations and with the help of customed trays. This work evaluated clinically the effectiveness and safety of two different concentrations of carbamide peroxide, when applied with individualized trays made with or without relief on the labial surface. Twenty-six patients were selected and submitted to tooth bleaching with 16% carbamide peroxide (superior dental arch) and 10% (inferior dental arch). The relief of the trays was applied exclusively in the semi-arches. The patients were randomly divided into two subgroups: the first subgroup was exposed to two hours daily, and the other one four hours daily. There was no significant evidence of differences between the studied groups after 14 days of bleaching treatment. However, it was possible to observe that the concentration of 16% employed for 04 hours/day was responsible for a higher incidence of trans-operative sensitivity, as well as mild gingival irritation. In conclusion, the concentrations of carbamide peroxide 10% and 16% were effective for the bleaching of naturally darkened teeth when used for a period of 14 days in trays with or withoutlabial relief; and the greater the concentration and time of exposure to the whitening agent, the greater the possibility of trans-operative sensitivity and gingival irritation.

Peroxide bleaching agent effects on enamel surface microhardness, roughness and morphology

O objetivo deste estudo foi avaliar a rugosidade, microdureza e morfologia superficial do esmalte dental humano tratado com seis agentes clareadores (antes e depois do tratamento). Amostras de esmalte dental humano foram obtidas de terceiros molares e aleatoriamente distribuídas em sete grupos (n = 11): controle, Whiteness Perfect - peróxido de carbamida a 10% (PC 10%), Colgate Platinum - PC 10%, Day White 2Z - peróxido de hidrogênio a 7,5% (PH 7,5%), Whiteness Super - PC 37%, Opalescence Quick - PC 35% e Whiteness HP - PH 35%. Os agentes clareadores foram aplicados de acordo com as instruções dos fabricantes. O grupo controle permaneceu sem tratamento e armazenado em saliva artificial. O teste de microdureza foi realizado com o indentador Knoop, e a rugosidade superficial foi verificada através do rugosímetro. Observações morfológicas foram realizadas através de microscopia eletrônica de varredura (MEV). Os resultados foram estatisticamente analisados com ANOVA (dois fatores) e teste Tukey (5%) e revelaram uma redução significante nos valores de microdureza e um aumento significante da rugosidade de superfície após o clareamento. Alterações na morfologia do esmalte após o clareamento foram observadas através de MEV. Concluiu-se que os agentes clareadores podem alterar a microdureza, rugosidade e morfologia superficial do esmalte dental.

Evaluación del blanqueamiento dentario de piezas teñidas con tetraciclina utilizando peróxido de carbamida al 10 por ciento con carbopol a largo plazo / A long-term evaluation of bleaching tetracycline-stained teeth using 10 per cent carbamide peroxide with carbopol

Las tinciones de los dientes por tetraciclina corresponden a una patología de tinción dentaria intrínseca adquirida, difícil de tratar por métodos no conservadores. El objeto de este estudio fue la aplicación de un blanqueamiento extendido con peróxido de carbamida al 10 por ciento con carbopol (Opalescence) con una cubeta individual de blanqueamiento nocturno por 4 horas diarias por 16 semanas, para verificar diferencias y la eficacia de este tratamiento en controles a las 8 y 16 semanas. Se seleccionaron 4 pacientes con sus dientes anterosuperiores teñidos con el antibiótico (24 dientes en total) que cumplieran requisitos específicos de salud y que aceptaran realizarse un tratamiento extendido sólo del maxilar superior. Se realizaron controles clínicos y fotográficos a las 2, 4, 8, 12 y 16 semanas. Para la muestra en cuestión, no se encontraron diferencias significativas en la cantidad de grises (o valor) entre los controles 0 y 8 semanas (mayor blanqueamiento dentario). Asimismo, se encontró un mayor grado de blanqueamiento entre 0 y 16 semanas y entre 8 y 16 semanas de control. El 100 por ciento de los pacientes presentó sensibilidad en los primeros controles no se evidenciaron cambios en el sabor e irritación gingival. Se concluye que el blanqueamiento extendido de dientes teñidos por tetraciclina logra un éxito para la muestra revisada, pero se requieren mayores estudios acerca de la regresión de las tinciones en el tiempo

Effects of some bleaching systems on the surface roughness of esthetic restorative materials

Home bleaching agents should not be used randomly when composite resin restorations are present. The patient must also realize that restorations frequently must be replaced to ensure proper shade matching if bleaching is successful. Finally, if posterior composite resin restorations are present, the patient should be instructed to be careful to confine the bleaching gel to the anterior segment of the tray

Efeito do flúor na eficácia do clareamento caseiro / Effects of fluoride in the efficacy of nightguard vital bleaching

O peróxido de carbamida a 10 por cento é amplamente utilizado para tratamento de dentes manchados. Um de seus efeitos adversos mais relatados é a presença de sensibilidade térmica; e para diminuí-la têm sido utilizados os fluoretos. No entanto, näo se sabe se o uso destes fluoretos prejudicaria o efeito clareador do peróxido de carbamida. Assim o objetivo deste estudo foi avaliar se a aplicaçäo de flúor conjuntamente com o peróxido de carbamida teria algum efeito deletério na cor final dos dentes clareados. Dez incisivos centrais superiores, recém extraídos por problemas periodontais, foram seccionados na regiäo do terço cervical da coroa através de um disco diamantado. A seguir o remanescente coronário foi novamente dividido em duas partes. A cor inicial de cada fragmento foi mensurada com o auxílio de um espectofotômetro utilizando a escala CIELab. Todos os fragmentos foram clareados por 8 horas diárias com peróxido de carbamida a 10 por cento (Opalescence-Ultradent) durante duas semanas. Após cada sessäo de 8 horas de clareamento os fragmentos do grupo 1 foram imersos em água destilada a 37ºC, enquanto que os fragmentos do grupo 2 sofreram aplicaçäo tópica de flúor neutro incolor 1,23 por cento, por quatro minutos antes de serem também imersos em água destilada (37ºC). Após este período de duas semanas, a cor final de cada fragmento foi mensurada novamente em um espectofotômetro da mesma forma que a cor inicial. Os dados foram submetidos à análise de variância em nível de 95 por cento de confiança. Os resultados do DE, que expressa a variaçäo de cor, foram os seguintes: grupo 1: 10,72 ñ 4,38; grupo 2: 13,30 ñ 4,56. O valor do DE de 3,3 é citado como sendo o valor clinicamente perceptível. Dessa forma é lícito concluir que: 1) o tratamento clareador com e sem aplicaçäo de flúor foi efetivo no clareamento dos dentes; 2) o uso do flúor concomitantemente ao tratamento clareador näo prejudicou a eficácia do clareamento caseiro

Estudo in vitro das alterações do esmalte dentário submetido à ação de um agente clareador / In vitro study of dental enamel alterations after exposing to a bleaching agent

O termo "clareamento dental" é citado desde 1898 na literatura odontológica, sendo que vários materiais já foram utilizados com este fim. Objetivando-se estudar in vitro os efeitos do agente clareador caseiro, peróxido de carbamida a 10 por cento, sobre o esmalte dentário humano, realizou-se uma análise em microscopia de luz polarizada a partir de 22 pré-molares extraídos. Tais dentes foram divididos em dois grupos de igual número, reservando-se dois para controle. O primeiro grupo foi submetido a três semanas de exposição ao agente clareador, sendo 21 períodos de 12 horas, intercalados por 12 horas de imersão em soro fisiológico. O segundo grupo foi exposto a 42 períodos de 12 horas, durante 6 semanas. Os resultados não mostraram alterações morfológicas do esmalte no primeiro grupo (três semanas), com aspecto bastante semelhante ao do grupo de controle. Entretanto, o segundo grupo (seis semanas), mostrou o esmalte alterado quando examinado à luz polarizada, exibindo aspectos atípicos e sugestivos de alterações estruturais