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OBJECTIVE: Evaluate the effectiveness and color stability of bleaching techniques on blood-stained teeth. MATERIAL AND METHODS: The teeth were stained by blood and allocated to groups: walking bleach, inside/outside, and in-office bleaching. L*, a*, b*, C*, h° color coordinates were measured using a clinical spectrophotometer at baseline, weekly (T1-T2-T3), and at 1-week (T4), 6-months (T5), and 1-year (T6) follow-up evaluations. ΔEab* , ΔE00 , and ΔWID were calculated between sequential evaluation timepoints and between baseline and each evaluation timepoint. Color coordinates and WID differences in each timepoint and technique were analyzed by Wilcoxon Signed Rank, Kruskal-Wallis and Mann-Whitney U test, respectively. ΔEab* , ΔE00 , and ΔWID were interpreted by color visual thresholds. RESULTS: The techniques presented a significant increase in L* and WID and, a significant decrease in a* and b* until the completion of treatments. Statistical differences between the techniques for a*, b* and WID were observed from T1 until T3. All techniques demonstrated excellent effectiveness for ΔEab* , ΔE00 , and ΔWID between baseline and each evaluation and follow-up timepoints. However, at T6, it was possible to identify a rebound effect for all techniques. CONCLUSIONS: All bleaching techniques presented excellent effectiveness. The stability of the whitening produced was maintained for 6 months. CLINICAL SIGNIFICANCE: Effective whitening of blood-stained teeth was achieved using walking bleach (sodium perborate), inside/outside (hydrogen peroxide - 7.5%) and in-office techniques (hydrogen peroxide - 35%). The bleaching techniques were effective after the completion of the treatments. A slight rebound was observed at 1 year follow-up.

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O clareamento dentário se apresenta como uma forma simples, econômica e eficaz com a finalidade de valorizar e devolver a estética do sorriso do paciente. Há hoje diferentes técnicas para realização do clareamento, podendo ser interno, externo ou combinada. O objetivo deste relato de caso é demonstrar a eficácia do clareamento dentário através da técnica combinada (mediata e imediata) em dente não vital escurecido por consequência de trauma. O paciente, do sexo masculino, 47 anos, compareceu ao consultório odontológico com a queixa principal de incômodo e insatisfação com a cor do dente. Paciente relatou queda na infância, e início de escurecimento há 10 anos; relatou quadro de dor no dente referido há 5 anos e tratamento endodôntico no mesmo período. Ao exame intraoral, foi notado o escurecimento do dente citado. Foi realizado um plano de tratamento, informando ao paciente o planejamento e riscos. A técnica escolhida foi a técnica combinada mediata ("walking bleaching", clareamento endógeno utilizando perborato de sódio com glicerina) e a imediata (clareamento de consultório, interno e externo utilizando peróxido de hidrogênio a 35%). A combinação das técnicas demonstrou ser eficaz e foi capaz de restabelecer a estética do paciente com sucesso.

Tooth whitening is presented as a simple, economical, and effective way to enhance and restore the aesthetics of the patient's smile. Today, there are different techniques for performing whitening, which can be internal, external, or combined. The objective of this case report is to demonstrate the effectiveness of tooth whitening through the combined technique (mediate and immediate) in a non-vital tooth discolored as a result of trauma. The patient, male, 47 years old, came to the dental office with the main complaint of discomfort and dissatisfaction with the color of his teeth. The patient reported falls in childhood and onset of darkening 10 years ago; he reported pain in the tooth referred for 5 years and endodontic treatment in the same period. On intraoral examination, a darkening of the cited tooth was noted. A treatment plan was carried out, informing the patient about the planning and risks. The technique chosen was the combined mediate technique ("walking bleaching", internal bleaching using sodium perborate with glycerin) and the immediate one (in-office, internal and external bleaching using 35% hydrogen peroxide). The combination of techniques proved to be effective and was able to successfully restore the patient's esthetics.

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Objetivo: O objetivo deste estudo foi avaliar as alterações químicas e morfológicas em esmalte, dentina e cemento após clareamento interno utilizando microscopia eletrônica de varredura e espectrometria de energia dispersiva. Materiais e Métodos: Setenta e dois incisivos bovinos foram preparados, cortados e clareados por 7 dias com os seguintes agentes clareadores: PH: gel de peróxido de hidrogênio 35%; PH + PS: gel de peróxido de hidrogênio 35% + perborato de sódio; PC: gel de peróxido de carbamida 37%; PC + PS: gel de peróxido de carbamida 37% + perborato de sódio; PS: perborato de sódio + água; e Controle: água deionizada. Os espécimes foram seccionados e preparados para análise em microscopia eletrônica de varredura e análise dos níveis de cálcio, fósforo, oxigênio e carbono usando espectrometria de energia dispersiva. Resultados: Foi observada uma redução significante nos níveis de cálcio em esmalte após clareamento com PC + PS e PC (p < 0,05). Os níveis de carbono (parte orgânica) foram alterados em esmalte. Uma redução significante nos níveis de cálcio foi encontrada na dentina nos grupos PH + PS, PC e PC + PS. Os níveis de fósforo aumentaram após o uso de PS (p < 0,05) e PC (p < 0,05). Níveis de carbono mostraram pequena variação e a maior quantidade foi encontrada nos grupos PC e PC + PS (p < 0,05), nos outros grupos não houve alteração. Uma redução significante nos níveis de cálcio foram encontradas no cemento no grupo PC + PS (p < 0,05). Conclusão: Alterações em esmalte, dentina e cemento ocorreram após o clareamento e essas alterações foram menos significantes quando utilizado perborato de sódio e água

Objective: The aim of this study was to evaluate the morphological and chemical alterations in enamel, dentin and cementum after internal bleaching using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). Material and Methods: Seventy-two bovine incisor teeth were prepared, cut and bleached for 7 days as follows: HP: 35% hydrogen peroxide gel; HP+SP: 35% hydrogen peroxide gel + sodium perborate; CP: 37% carbamide peroxide gel; CP+SP: 37% carbamide peroxide gel + sodium perborate; SP: sodium perborate + water; and control: deionized water. The specimens were sectioned and prepared for morphological analysis under SEM and analysis of calcium, phosphorus, oxygen and carbon levels using EDS. Results: A significant reduction was found in the calcium levels in enamel after treatment with CP + SP and CP (p < 0.05). Carbon (organic part) was hardly altered in enamel. A significant reduction in the calcium levels was found in dentin in Groups HP+SP, CP and CP+SP. Phosphorus levels increased after SP+H20 (p < 0.05) and CP (p < 0.05). Carbon levels showed little variation and the largest amount was found in Groups CP and CP+SP (p < 0.05); in the other groups there was no alteration. A significant reduction in the calcium levels was found in the cementum in Group CP+SP (p < 0.05). Conclusion: Alterations in the enamel, dentin and cementum compositions occurred after bleaching and these alterations showed to be less significant with sodium perborate and water.

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AIM: To assess the discolouration of teeth with closed and open apices after placement of triple antibiotic paste (TAP, ciprofloxacin, metronidazole and minocycline) in the pulp chamber and whether discolouration could be reversed by internal bleaching procedures. METHODOLOGY: Twenty extracted human mandibular premolars were divided into 2 groups (n = 10): teeth with closed apices (CA) and teeth with open apices (OA). After conventional access, the TAP was sealed in the pulp chamber for 3 weeks. The paste was removed by a rinse with sodium hypochlorite (NaOCl) and a mixture of sodium perborate and distilled water was sealed in the pulp chamber for 1, 2 and 3 weeks. The shade was measured by a spectrophotometer at six time periods: baseline (T0), after 3 weeks of placement of TAP (T1), after removal of TAP with a NaOCl rinse (T2) and after 1 (T3), 2 (T4) and 3 (T5) weeks of internal bleaching with sodium perborate paste. Data were collected based on the CIELAB-CIE1976 (L*a*b*) system and analysed using t-tests and anova. RESULTS: A significant decrease in the mean values of L* (lightness) was observed after treatment with TAP (T1, P < 0.05). Considerable increases in these values after bleaching with sodium perborate (T3 < T4 < T5) were found in both groups. The only significant difference in the intergroup analysis was between T1 and T2, in which ΔE values in the OA group were higher (P = 0.04). CONCLUSIONS: TAP discoloured the tooth structure, but discolouration could be reversed with sodium perborate paste. In general, teeth with closed and open apices had the same rates of discolouration and bleaching.

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Introdução e objetivo: Buscou-se quantificar, indiretamente, a liberaçãode oxigênio após a reação química intracoronária, por deslocamentoaxial de fluido em capilares de vidro, adaptados em coroas dentárias.Material e métodos: Coroas bovinas foram acessadas, e foi executadoo tampão cervical e posicionado um capilar de vidro na face externavestibular, contendo um veículo oleoso. Na sequência, foram preparadasquatro associações de clareadores e colocadas em seu interior: G1? perborato de sódio e peróxido de hidrogênio a 3%; G2 ? perborato de sódio e água; G3 ? associação de percarbonato de sódio e peróxidode hidrogênio a 3%; G4 ? associação de percarbonato de sódio eágua destilada. Após serem mantidas por 24 horas, quantificou-se odeslocamento axial do fluido, interpretado como liberação de oxigêniopela reação química. Resultados: Os resultados mostraram umatendência das associações com o peróxido de hidrogênio em promovermaior liberação de oxigênio. Entretanto não houve diferença entre operborato de sódio e o percarbonato de sódio (p > 0,05). Conclusão:Os grupos experimentais não demonstraram diferenças entre si duranteas 24 horas de reação química.

Objective: To indirectly quantify the release of oxygen after intracoronarychemical reaction, by axial displacement of fluid in glass capillariesarranged in dental crowns. Material and methods: Bovine crownswere accessed, the cervical plug was executed and a glass capillarywas placed in the vestibular external face, containing an oily vehicle.Following that, four associations of bleaching were prepared and placedin its interior: G1 ? sodium perborate and hydrogen peroxide 3%; G2? sodium perborate and water, G3 ? sodium percarbonate and hydrogenperoxide 3%; G4 ? sodium percarbonate and distilled water. After beingkept for 24 hours, the axial displacement of the fluid was quantifiedand interpreted as the release of oxygen by the chemical reaction.Results: The results showed a trend of the associations with hydrogenperoxide to promote the release of more oxygen. However, there wasno difference between sodium perborate and sodium percarbonate(p > 0.05). Conclusion: The experimental groups showed no differencesbetween them during the 24 hours of chemical reaction.

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Objective: To evaluate the efficacy of 16% carbamide peroxide gel (CP16%), tetrahydrate sodium perborate (SP) and mixture (CP16% + SP), in walking bleaching of non-vital discolored teeth. Materials and methods: Sixty single-rooted human premolars with intact crowns were used and initial color was assessed using Vita shade guide and standardized photos. The teeth were stained using rabbit fresh blood for 18 days and photos of discolored teeth and color evaluation were performed. The teeth were divided into 4 groups (n= 15), according to bleaching agent used: G1) CP16% gel; G2) CP16% gel + SP; G3) SP + distilled water; G4: control.The bleaching agents were replaced twice at 7-day intervals for 21 days. All teeth were evaluated by two endodontists at days 0, 7, 14 and 21 and the color changes were assessed using Vita shade guide and standardized photos. The results were analyzed byKruskal-Wallis and Dunn’s tests (p=0.05). Results: The experimental groups presented statistically similar bleaching results (p>0.05) at the end of 7, 14 and 21 days. These groups presented significantly higher bleaching efficacy than control group (G4) (p<0.05). The mixture CP16% + SP promoted return of original color in 100% of teeth at the end of 21 days. Conclusion: It was concluded that three bleaching agents were effective in bleaching of stained teeth with blood products, especially at the end of 21 days.

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