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

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

Influência do peróxido e do uso de diferentes substâncias de combate à dor na inflamação e na expressão de neuropeptídeos pró-inflamatórios após o tratamento clareador

O objetivo do presente estudo foi avaliar a influência da hidrocortison e do acetaminofeno na inflamação e na expressão de neuropeptídeos por meio da análise histopatológica e imunoistoquímica. Para tanto, 63 ratos foram divididos em 3 lotes de estudo (n=21) de acordo com a terapia de combate à dor: LI- controle, LII- administração tópica de hidrocortisona por 10 minutos, depois do tratamento clareador e LIII- administração via oral de acetaminofeno 30 minutos antes do tratamento clareador com peróxido de hidrogênio a 35% e depois de 12 em 12 horas. Em todos os grupos de estudo, na maxila esquerda foi realizado o tratamento clareador placebo e a maxila direita recebeu a 3 aplicações de 15 minutos de um gel clareador a base de peróxido de hidrogênio a 35%, totalizando 45 minutos de contato do gel clareador com substrato dentário. Os momentos de eutanásia dos animais foram imediatamente após, 24 e 48 horas após o tratamento clareador. Posteriormente à eutanásia dos animais, as peças foram processadas e o primeiro molar de cada maxila foi analisado histopatologicamente quanto ao grau de inflamação e por análise de imunoistoquímica para verificarmos a presença dos neuropeptídeos SP e CGRP. Os dados obtidos foram submetidos ao teste estatístico não paramétrico Kruskal Wallis seguido do teste de Dunn para comparações individuais, sendo observado na análise histopatológica total desorganização celular, extensas áreas de necrose nos grupos clareados, e o grupo que recebeu tratamento com otosporim apresentou melhores resultados. Na análise imuno-histoquimica, obteve imunomarcação positiva em todos os grupos, inclusive controle, porém nos grupos clareados a imunomarcação foi mais forte, sendo que o grupo que recebeu tratamento com otosporim apresentou os melhores resultados. Conclui-se que o uso da hidrocortisona após tratamento clareador minimiza os efeitos colaterais deste procedimento estético.The aim of this study was to evaluate the influence of hydrocortisone and acetaminofen substances in inflammation and neuropeptide expression by histopathologic and immunohistochemical analysis. For this, 63 rats were divided into 3 batches of study (n = 21) according to combat pain therapy: Li control LII- topical administration of Otosporin® for 10 minutes after the bleaching treatment and administration route LIIIoral Tylenol® 30 minutes before the bleaching with hydrogen peroxide at 35% and then 12 for 12 hours. In all study groups in left maxilla was performed treatment whitener placebo and right jaw received three applications of 15 minutes a whitening gel 35% hydrogen peroxide base, totaling 45 minutes of contact of the whitening gel dental substrate. The times of the animals were euthanized immediately after 24 and 48 hours after the bleaching treatment. After the euthanasia of animals, the pieces were processed and the first molar of each jaw was analyzed histologically the degree of inflammation and analysis of immunohistochemistry to verify the presence of the neuropeptides SP and CGRP. The data were submitted to statistical nonparametric Kruskal Wallis test followed by Dunn's test for individual comparisons, being observed on histopathologic total cellular disorganization analysis, extensive areas of necrosis in whitened groups, and the group that received treatment with Otosporin® showed better results. In immunohistochemical analysis, obtained positive immunostaining in all groups, including control, but the whitened immunostaining groups was stronger, and the group that received treatment with Otosporin® showed the best results. We conclude that the use of Otosporin® after bleaching treatment minimizes the side effects of this cosmetic procedure.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Pulp response of rats submitted to bleaching and the use of different anti-inflammatory drugs.

This study aimed to evaluate neuropeptide expression after bleaching treatment using histopathological and immunohistochemical analyses and the effects of hydrocortisone and acetaminophen on pulp inflammation, sine dental bleaching and inflammation first occur, and only then, the treatmentt. Sixty-three rats were divided into three groups (n = 21) according to the pain-relieving therapy used: I-control; II-topical application of Otosporin for 10 min after the bleaching treatment; III-oral administration of paracetamol 30 min before whitening and then every 12h. In all the study groups, placebo gel was applied to the left upper jaw (control) and a 35% H2O2-based whitening gel was applied to the right upper jaw for 45 min. Seven animals from each group were euthanized at different time points: 0h after treatment, 24h, and 48h. After euthanasia, the first molar on each side was analyzed by histology and immunohistochemistry to assess the degree of inflammation and verify the presence of the neuropeptides, substance P (SP) and calcitonin gene-related peptide (CGRP). The data were analyzed using the statistical nonparametric Kruskal-Wallis test followed by Dunn's test for individual comparisons. Extensive areas of necrosis were observed in the groups that received bleaching treatment only, whereas reduced damage were obtained in the group treated with Otosporin. The immunohistochemical analysis showed positive immunolabeling in all groups, including the control, but this was stronger in the groups that received bleaching treatment. The best results were obtained in the group that received treatment with Otosporin. The use of Otosporin after dental bleaching minimized the side effects of this treatment

Demineralization and hydrogen peroxide penetration in teeth with incipient lesions

The aim of this study was to evaluate the demineralization and hydrogen peroxide (HP) penetration in teeth with incipient lesions submitted to bleaching treatment. For analysis of HP penetration, sound and demineralized enamel/dentin discs were placed in artificial pulp chambers containing acetate buffer solution. After bleaching treatment, this solution was subjected for analysis of optical density by spectrophotometry and the disc surfaces were analyzed with scanning electron microscopy (SEM) and polarized light microscopy (PLM). The remaining discs were subjected for cross-sectional hardness analysis at different depths. Data were analyzed by repeated measures ANOVA and PLSD Fisher test (a=0.05). It was observed that previously demineralized teeth showed greater HP penetration (p<0.05). The bleaching treatment caused changes to a depth of 20 µm in sound enamel and up to 90 µm in demineralized enamel. SEM and PLM images revealed that the bleaching treatment caused superficial changes that were considerably more accentuated in previously demineralized teeth. It may be concluded that the enamel mineralization level influences HP penetration and the bleaching agent contributed to increase the demineralization depth.O objetivo deste estudo foi avaliar a desmineralização e a penetração do peróxido de hidrogênio (HP) em dentes com lesões incipientes submetidos ao tratamento clareador. Para analisar a penetração do peróxido de hidrogênio, discos de esmalte/dentina hígidos e desmineralizados foram posicionados em câmaras pulpares artificiais contendo solução tampão de acetato. Após o tratamento clareador, esta solução foi submetida à análise da densidade óptica no espectrofotômetro e as superfícies dos discos foram analisadas por meio de microscopia eletrônica de varredura (MEV) e microscopia de luz polarizada (MLP). Os discos restantes foram submetidos à análise de microdureza transversal em diferentes profundidades. Os dados foram submetidos aos testes ANOVA e teste PLSD Fisher (α= 5%). Observou-se que os dentes previamente desmineralizados mostraram maior penetração de HP (p<0,05). O tratamento clareador causou alterações em uma profundidade de 20 μm em esmalte hígido e até 90 μm em esmalte desmineralizado. As imagens obtidas em PLM e MEV mostraram que o tratamento clareador promove alterações superficiais no esmalte, sendo mais pronunciadas em dentes previamente desmineralizados. Foi concluído que o nível de mineralização do esmalte influencia a penetração do PH e que o agente clareador contribuiu para o aumento da profundidade de desmineralização.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Color alteration, hydrogen peroxide diffusion, and cytotoxicity caused by in-office bleaching protocols

Objectives This study evaluated the color alteration, cytotoxicity, and hydrogen peroxide (HP) diffusion associated with different in-office bleaching protocols. Materials and methods Bovine enamel/dentin disks were subjected to three bleaching sessions with 35 % HP (three 15-min applications), 35 % HP (one 45-min application), or 20 % HP (one 45-min application). The control group was not bleached. Before bleaching, the disks were adapted to artificial pulp chambers positioned in compartments containing 1 ml of acetate buffer or medium, so that the dentin remained in contact with these substances. Immediately after bleaching, the HP that diffused through the disks was stabilized by acetate buffer and was quantified (two-way repeated measures ANOVA/Fisher’s protected least significant difference (PLSD) test; α=5 %). Cells of mouse dental papilla cell-23 (MDPC-23) were incubated in this culture media for 1 h, followed by analysis of cellular metabolism (methyl tetrazolium assay) (one-way ANOVA/Tukey test; α=5 %) and morphology (scanning electron microscopy). The specimen color alteration (ΔE) was analyzed by reflection spectrophotometry (two-way repeated measures ANOVA/Fisher’s PLSD test; α=5 %). Results All protocols showed equal effectiveness at the end of the treatment. HP diffusion was significantly higher in the groups bleached with 35 % HP. Reapplication of 35 % HP resulted in increased diffusion only in the first session; however, the decrease in cell metabolism was similar for all studied protocols. Conclusion Despite greater peroxide diffusion in the groups treated with 35 % HP, all protocols showed the same effectiveness and were cytotoxic to MDPC-23 cells. Clinical relevance Bleaching protocols using high HP concentrations should be avoided because they exert aggressive actions on odontoblast-like cells.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

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

<div><p>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.</p></div