Assessment of the regenerative potential of macro-porous chitosan-calcium simvastatin scaffolds on bone cells.

This study evaluated the bioactive potential of a macro-porous chitosan scaffold incorporated with calcium hydroxide (CH-Ca) and functionalized with bioactive doses of simvastatin (SV) for bone tissue regeneration. Initially, the bioactive dose of SV in osteoblastic cells (SAOS-2) was determined. For the direct contact experiment, SAOS-2 cells were plated on scaffolds to assess cell viability and osteogenic differentiation. The second assay was performed at a distance using extracts from scaffolds incubated in culture medium to assess the effect of conditioned medium on viability and osteogenic differentiation. The initial screening showed that 1 µM SV presented the best biostimulating effects, and this dose was selected for incorporation into the CH-Ca and pure chitosan (CH) scaffolds. The cells remained viable throughout the direct contact experiment, with the greatest cell density in the CH-Ca and CH-Ca-SV scaffolds because of their higher porosity. The CH-Ca-SV scaffold showed the most intense bio-stimulating effect in assays in the presence and absence of osteogenic medium, leading to an increased deposition of mineralized matrix. There was an increase in the viability of cells exposed to the extracts for CH-Ca, CH-SV, and CH-Ca-SV during the one-day period. There was an increase in ALP activity in the CH-Ca and CH-Ca-SV; however, the CH-Ca-SV scaffold resulted in an intense increase in the deposition of mineralized nodules, approximately 56.4% at 7 days and 117% at 14 days, compared with CH (control). In conclusion, functionalization of the CH-Ca scaffold with SV promoted an increase in bioactivity, presenting a promising option for bone tissue regeneration.

Assessment of the regenerative potential of macro-porous chitosan-calcium simvastatin scaffolds on bone cells

Abstract This study evaluated the bioactive potential of a macro-porous chitosan scaffold incorporated with calcium hydroxide (CH-Ca) and functionalized with bioactive doses of simvastatin (SV) for bone tissue regeneration. Initially, the bioactive dose of SV in osteoblastic cells (SAOS-2) was determined. For the direct contact experiment, SAOS-2 cells were plated on scaffolds to assess cell viability and osteogenic differentiation. The second assay was performed at a distance using extracts from scaffolds incubated in culture medium to assess the effect of conditioned medium on viability and osteogenic differentiation. The initial screening showed that 1 μM SV presented the best biostimulating effects, and this dose was selected for incorporation into the CH-Ca and pure chitosan (CH) scaffolds. The cells remained viable throughout the direct contact experiment, with the greatest cell density in the CH-Ca and CH-Ca-SV scaffolds because of their higher porosity. The CH-Ca-SV scaffold showed the most intense bio-stimulating effect in assays in the presence and absence of osteogenic medium, leading to an increased deposition of mineralized matrix. There was an increase in the viability of cells exposed to the extracts for CH-Ca, CH-SV, and CH-Ca-SV during the one-day period. There was an increase in ALP activity in the CH-Ca and CH-Ca-SV; however, the CH-Ca-SV scaffold resulted in an intense increase in the deposition of mineralized nodules, approximately 56.4% at 7 days and 117% at 14 days, compared with CH (control). In conclusion, functionalization of the CH-Ca scaffold with SV promoted an increase in bioactivity, presenting a promising option for bone tissue regeneration.

An organotypic model of oral mucosa cells for the biological assessment of 3D-printed resins for interim restorations.

STATEMENT OF PROBLEM: Three-dimensionally (3D) printed resins have become popular as a new class of materials for making interim restorations. However, little is known about how the fabrication parameters can influence biological compatibility with oral tissues. PURPOSE: The purpose of this in vitro study was to evaluate the effect of the postpolymerization time on the cytotoxicity of resins for printing interim restorations by using a 3D organotypic model of the oral mucosa. MATERIAL AND METHODS: Cylindrical specimens were prepared with conventional acrylic resin (AR), computer-aided design and computer-aided manufacture (CAD-CAM) resin (CC), composite resin (CR), and 2 resins for 3D printing (3DP) marketed as being biocompatible. The 3DPs were submitted to postpolymerization in an ultraviolet (UV) light chamber for 1, 10, or 20 minutes (90 W, 405 nm). Standard specimens of the materials were incubated for 1, 3, and 7 days in close contact with an organotypic model of keratinocytes (NOK-Si) in coculture with gingival fibroblasts (HGF) in a 3D collagen matrix, or directly with 3D HGF cultures. Then, the viability (Live/Dead n=2) and metabolism (Alamar Blue n=6) of the cells were assessed. Spectral scanning of the culture medium was performed to detect released components (n=6) and assessed statistically with ANOVA and the Tukey post hoc test (α=.05). RESULTS: Severe reduction of metabolism (>70%) and viability of keratinocytes occurred for 3DP resin postpolymerized for 1 minute in all periods of analysis in a time-dependent manner. The decrease in cell metabolism and viability was moderate for the 3D culture of HGFs in both experimental models, correlated with the intense presence of resin components in the culture medium. The resins postpolymerized for 10 and 20 minutes promoted a mild-moderate cytotoxic effect in the period of 1 day, similar to AR. However, recovery of cell viability occurred at the 7-day incubation period. The 3DP resins submitted to postpolymerization for 20 minutes showed a pattern similar to that of CR and CC at the end of the experiment. CONCLUSIONS: The cytotoxic potential of the tested 3DP resins on oral mucosa cells was influenced by postprinting processing, which seemed to have been related with the quantity of residual components leached.

Pro-inflammatory mediators expression by pulp cells following tooth whitening on restored enamel surface.

This paper aimed to assess the influence of adhesive restoration interface on the diffusion of hydrogen peroxide (H2O2), indirect toxicity, and pro-inflammatory mediators expression by odontoblast-like cells, after in-office tooth whitening. Dental cavities prepared in bovine enamel/dentin discs were adhesively restored and subjected or not to hydrolytic degradation (HD). A whitening gel with 35% H2O2 (WG) was applied for 45 min onto restored and non-restored specimens adapted to artificial pulp chambers giving rise to the groups: SD- intact discs (control); SD/HP- whitened intact discs; RT/HP- restored and whitened discs; and RT/HD/HP- restored and whitened discs subjected to HD. The extracts (culture medium + WG components diffused through enamel/dentin/restoration interface) were collected and applied to odontoblast-like MDPC-23 cells. The study evaluated the amount of H2O2 in the extracts, as well as the cell viability (CV), cell morphology (CM), and gene expression of inflammatory mediators (TNF-α and COX-2) by the pulp cells exposed to the extracts (ANOVA and Tukey tests; 5% significance). All whitened groups presented lower CV than SD (control; p<0.05). The highest CV reduction and gene expression of TNF-α and COX-2 was observed in the RT/HD/HP group in comparison with SD/HP and RT/HP (control; p<0.05). CM alterations occurred in all whitened groups. The intensity of these cell side effects was directly related with the amount of H2O2 in the extracts. We concluded that adhesive restoration of dental cavity increases the H2O2 diffusion after in-office whitening, enhancing the indirect toxicity of this therapy and trigger pro-inflammatory overexpression by MDPC-23 cells.

Pro-inflammatory mediators expression by pulp cells following tooth whitening on restored enamel surface

Abstract This paper aimed to assess the influence of adhesive restoration interface on the diffusion of hydrogen peroxide (H2O2), indirect toxicity, and pro-inflammatory mediators expression by odontoblast-like cells, after in-office tooth whitening. Dental cavities prepared in bovine enamel/dentin discs were adhesively restored and subjected or not to hydrolytic degradation (HD). A whitening gel with 35% H2O2 (WG) was applied for 45 min onto restored and non-restored specimens adapted to artificial pulp chambers giving rise to the groups: SD- intact discs (control); SD/HP- whitened intact discs; RT/HP- restored and whitened discs; and RT/HD/HP- restored and whitened discs subjected to HD. The extracts (culture medium + WG components diffused through enamel/dentin/restoration interface) were collected and applied to odontoblast-like MDPC-23 cells. The study evaluated the amount of H2O2 in the extracts, as well as the cell viability (CV), cell morphology (CM), and gene expression of inflammatory mediators (TNF-α and COX-2) by the pulp cells exposed to the extracts (ANOVA and Tukey tests; 5% significance). All whitened groups presented lower CV than SD (control; p<0.05). The highest CV reduction and gene expression of TNF-α and COX-2 was observed in the RT/HD/HP group in comparison with SD/HP and RT/HP (control; p<0.05). CM alterations occurred in all whitened groups. The intensity of these cell side effects was directly related with the amount of H2O2 in the extracts. We concluded that adhesive restoration of dental cavity increases the H2O2 diffusion after in-office whitening, enhancing the indirect toxicity of this therapy and trigger pro-inflammatory overexpression by MDPC-23 cells.

Resumo Este trabalho teve como objetivo avaliar a influência da interface de uma restauração adesiva na difusão do peróxido de hidrogênio (H2O2), toxicidade indireta e expressão de mediadores pró-inflamatórios por células odontoblastóides, após clareamento dental em consultório. Cavidades dentárias preparadas em discos de esmalte / dentina foram restauradas com adesivo e submetidas ou não à degradação hidrolítica (HD). Um gel clareador com 35% H2O2 (WG) foi aplicado por 45 min em discos restaurados e não restaurados adaptados às câmaras pulpares artificiais dando origem aos grupos: SD- discos intactos (controle); SD / HP - Discos intactos clareados; RT / HP - discos restaurados e clareados; e RT / HD / HP - discos restaurados, clareados e submetidos a HD. Os extratos (meio de cultura + componentes WG difundidos através da interface esmalte/dentina/restauração) foram coletados e aplicados em células odontoblastóides MDPC-23. Foi avaliada a quantidade de H2O2 nos extratos, bem como a viabilidade (CV), morfologia (CM) e expressão gênica de mediadores inflamatórios (TNF-α e COX-2) pelas células pulpares expostas aos extratos (ANOVA e testes de Tukey; 5% de significância). Todos os grupos clareados apresentaram menor CV do que SD (controle; p <0,05). A maior redução CV e expressão gênica de TNF-α e COX-2 foi observada no grupo RT / HD / HP em comparação com SD / HP e RT / HP (controle; p <0,05). Alterações na CM ocorreram em todos os grupos clareados. A intensidade desses efeitos celulares teve relação direta com a quantidade de H2O2 nos extratos. Concluímos que a presença de uma cavidade contendo restauração adesiva aumenta a difusão de H2O2 após o clareamento em consultório, o que, por sua vez, aumenta a toxicidade indireta dessa terapia e desencadeia a expressão de mediadores pró-inflamatórios pelas células pulpares MDPC-23.

Mineral-induced bubbling effect and biomineralization as strategies to create highly porous and bioactive scaffolds for dentin tissue engineering.

The objective of the study was to assess the biological and mechanical characteristics of chitosan-based scaffolds enriched by mineral phases and biomineralized in simulated body fluid (SBF) as a possible biomaterial for dentin regeneration. Thus, porous chitosan scaffolds were prepared by the mineral-induced bubbling-effect technique and subjected to biomineralization to create biomimetic scaffolds for dentin tissue engineering. Suspensions containing calcium hydroxide, nanohydroxyapatite, or ß-tricalcium phosphate were added to the chitosan (CH) solution and subjected to gradual freezing and freeze-drying to obtain CHCa, CHnHA, and CHßTCP porous scaffolds, respectively, by the bubbling effect. Then, scaffolds were incubated in SBF for 5 days at 37°C, under constant stirring, to promote calcium-phosphate (CaP) biomineralization. Scanning electron microscopy revealed increased pore size and porosity degree on mineral-containing scaffolds, with CHCa and CHnHA presenting as round, well-distributed, and with an interconnected pore network. Nevertheless, incubation in SBF disrupted the porous architecture, except for CHCaSBF , leading to the deposition of CaP coverage, confirmed by Fourier Transform Infrared Spectroscopy analyses. All mineral-containing and SBF-treated formulations presented controlled degradation profiles and released calcium throughout 28 days. When human dental pulp cells (HDPCs) were seeded onto scaffold structures, the porous and interconnected architecture of CHCa, CHnHA, and CHCaSBF allowed cells to infiltrate and spread throughout the scaffold structure, whereas in other formulations cells were dispersed or agglomerated. It was possible to determine a positive effect on cell proliferation and odontogenic differentiation for mineral-containing formulations, intensely improved by biomineralization. A significant increase in mineralized matrix deposition (by 8.4 to 18.9 times) was observed for CHCaSBF , CHnHASBF , and CHßTCPSBF in comparison with plain CH. The bioactive effect on odontoblastic marker expression (ALP activity and mineralized matrix) was also observed for HDPCs continuously cultivated with conditioned medium obtained from scaffolds. Therefore, biomineralization of chitosan scaffolds containing different mineral phases was responsible for increasing the capacity for mineralized matrix deposition by pulpal cells, with potential for use in dentin tissue engineering.

Influence of pain-relieving therapies on inflammation and the expression of proinflammatory neuropeptides after dental bleaching treatment.

OBJECTIVES: To minimize the tooth sensitivity caused by in-office bleaching, many dentists use non-steroidal anti-inflammatory drugs and topical desensitizing gels containing potassium nitrate and sodium fluoride. This study aimed to evaluate the influence of these substances on inflammation and the expression of substance P and calcitonin gene-related peptide in pulp nerve fibers. MATERIALS AND METHODS: Seventy-two rats were divided into 6 groups as follows: GI, control; GII, only dental bleaching; GIII, only ibuprofen; GIV, ibuprofen administered 30 minutes before and after the bleaching treatment and every 12 hours until the analysis; GV, only topical application of a desensitizing agent; and GVI, topical application of a desensitizing agent before dental bleaching. Placebo gel was applied to the upper left jaw and the bleaching agent was applied to the upper right jaw in all groups. Subsequently, the groups were divided into 3 subgroups based on the time of analysis: 0, 24, and 48 hours after bleaching (n = 8). The rats were euthanized and the maxillae were processed and evaluated by histopathological and immunohistochemical analyses. The data were analyzed using the Kruskal-Wallis test, followed by the Dunn test (p < 0.05). RESULTS: In the bleaching groups, the inflammatory process and expression of neuropeptides decreased over time. The animals in which a desensitizing agent was applied showed better results within 24 hours. CONCLUSIONS: The use of a desensitizing agent had positive effects on inflammation and pain-related neuropeptide expression, minimizing the painful effects of dental bleaching treatment.

Evaluation of the color change and tooth sensitivity in treatments that associate violet LED with carbamide peroxide 10 %: A randomized clinical trial of a split-mouth design.

BACKGROUND: To evaluate the bleaching efficacy and post-operative sensitivity of 10 % carbamide peroxide (PC) with or without violet LED (VL). METHODS: Thirty patients were selected and were instructed to perform home bleaching treatment using PC 10 %, for 8 h daily, for 21 days. All patients underwent in-office irradiation of only one hemiarch with VL for 30 min, twice per week for three weeks, totaling six clinical sessions of irradiation. The treatment used for each hemiarch was determined randomly. The analyses were performed at the initial time and 7, 14, and 21 days after the start of treatment and 7 and 14 days after the end of the bleaching treatment. For color analysis, digital spectrophotometry was done using the Visual Analog Scale and cold detection was performed using the thermo-sensory analysis II (TSA II) equipment. The ANOVA-two way with repeated measures and the Tukey test (α = 0.05) were used for the color and cold sensitivity analysis. RESULTS: On analyzing the color change, it was observed that the hemiarch that was irradiated with VL presented the highest values compared with the side that did not receive irradiation. Regarding tooth sensitivity, there was no report of any patient experiencing discomfort during the bleaching protocol. Analysis of the dental thermal sensation threshold showed that the use of VL made the teeth more sensitive. CONCLUSIONS: It can be concluded that the VL provided a positive effect on color alteration when used in conjunction with 10 % PC. However, the use of this new protocol made the teeth more sensitive.

Adequação do meio bucal para restaurações estéticas: relato de caso / Suitability of the buccal medium for aesthetic restorations: case report

Para restabelecer a função e estética dos elementos dentários é importante realizar a adequação do meio bucal antes de procedimentos restauradores definitivos, visando reduzir fatores ou nichos que favorecem para o acúmulo de placa; controlando a colonização microbiana cariogênica e proporcionando ao paciente um controle mais efetivo de sua higiene bucal. Este trabalho tem como objetivo relatar um caso clínico em que foi realizado adequação do meio bucal para posterior realização de restaurações estéticas em dentes ântero-superiores acometidos pela doença carie dentária. Concluise que é de suma importância realizar a adequação do meio bucal, controle da dieta e motivação do paciente com sua higienização bucal antes de realizar procedimentos restauradores definitivos, para obter êxito no restabelecimento da função e da estética(AU)

To restore a function and aesthetics of the dental elements, it is important to make an adjustment of the buccal environment before restorative procedures are defined, the presence of factors or niches that favor plaque accumulation; controlling the cariogenic microbial colonization and providing a more effective control of its oral hygiene. The objective of this study was to conduct a clinical study in which women performed exercises for dental caries disease. It concludes that it is important to achieve a correct oral sense, diet control and motivation for oral hygiene before performing definitive restorative procedures, so that medical care is not restored to function and aesthetics(AU)

Clinical analysis of color change and tooth sensitivity to violet LED during bleaching treatment: A case series with split-mouth design.

BACKGROUND: The aim of this study was to analyze bleaching treatment performed with different products, with or without the use of Violet LED. METHODS: The color and dental sensitivity of six patients were evaluated as follows: (1)at-home bleaching with 10% Carbamide Peroxide (CP); (2)in-office bleaching with 17.5% Hydrogen Peroxide (HP), and (3)treatment with a placebo gel. All patients, including patients receiving at-home bleaching, received irradiation with violet LED in the office. The right hemiarch was protect with silicone. The color was evaluated using Vita Easyshade digital spectrophotometer and the Vita scale on teeth 13-23. Visual analog scale sensitivity analysis was performed per hemiarch, while the thermal sensation threshold was performed on teeth 11, 13, 21 and 23. RESULTS: Regarding the color change (ΔE) it can be observed that treatment 1, in which 10%CP was used, presented the highest values, followed by treatment 2, in which 17.5%HP was used. Regarding sensitivity, only patients who received 17.5%HP showed moderate sensitivity, and there was no difference between the arches. The analysis of dental thermal sensation threshold showed that there was more dental sensitization between 7 and 14 days and that the use of violet LED made the teeth more sensitive. CONCLUSIONS: It was concluded that violet LED enhanced the bleaching effect when used with 10%PC gels, and a discreet effect was seen when used either in conjunction with 17.5%PH or alone. Violet LED had no effect on pain sensation, but increased the detection threshold of thermal changes in the teeth that were irradiated.

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.

Análise da eficácia clareadora e dos efeitos adversos provocados pelo uso da luz violeta no clareamento dental / Analysis of the bleaching efficacy and adverse effects caused by the use of violet light in dental bleaching

Pesquisadores tem proposto um clareamento dentário apenas com a irradiação da Luz violeta (VIO), sem a necessidade do gel clareador. Portanto foi o objetivo deste trabalho avaliar in vitro e in vivo este novo tratamento associado com diferentes concentrações de peróxido de hidrogênio (PH) quanto a sua eficácia clareadora e os possíveis efeitos adversos. Para o estudo in vitro, foram selecionados 567 (n=67) dentes e distribuídos em 9 grupos: Sem Gel(SG)-Sem Luz(SL), PH17,5%-SL, PH35%-SL, SGLED/Laser(LED), PH17,5%-LED, PH35%-LED, SG-VIO, PH17,5%-VIO e PH35%-VIO. A aplicação dos géis seguiu as recomendações do fabricante. O LED foi irradiada 3 vezes de 3 minutos, a VIO foi irradiada 3 vezes de 7 minutos. Após os procedimentos clareadores, foram realizadas as análises de alteração cromática superficial e intensidade de fluorescência (n=10), considerando 5 tempos de análise (T0-inicial, T1- 1º sessão, T2-2º sessão, T3-3º sessão, T4-14 dias após), alteração de cor em profundidade (n=15), condutância hidráulica (n=10), difusão do PH (n=10), viabilidade celular (n=8) e a variação da temperatura intrapulpar (n=10). Os dados foram submetidos à testes estatísticos adequados para cada tipo de análise. A VIO quando utilizado isoladamente proporcionou alterações cromáticas superficiais e em profundidade, mas seu efeito foi estatisticamente menor do que o proporcionado pelo gel clareador. Na fluorescência, o T1 e T3 do PH35%-SL foram diferentes. A difusão do PH e a permeabilidade dentária, os grupos PH35% apresentou os maiores valores, sendo potencializado quando associado com LED/Laser. No metabolismo celular, os grupos PH35% apresentaram os menores valores, e a VIO isolado aumentou a temperatura intrapulpar e diminuição da viabilidade celular. Para a parte in vivo do estudo, inicialmente foram selecionados 6 pacientes e distribuídos em 3 tratamentos para o estudo piloto (n=2): Peróxido de Carbamida (PC) 10%+VIO, VIO e PH17,5%+VIO. Somente o lado direito associou a irradiação com a VIO com gel clareador, enquanto que o lado esquerdo recebeu apenas a aplicação do gel clareador. Foram realizadas 9 sessões clínicas, sendo que em cada sessão, foram realizadas 20 irradiações de 1 minuto com intervalo de 30 segundos. Os pacientes que receberam PC10%+VIO apresentaram maior diferença entre as hemi-arcadas, com resultados positivos para o lado que recebeu a associação com a luz, porém constatou-se maior sensibilidade dentária nesta associação. No segundo estudo, foi selecionado o tratamento com a maior diferença observada no estudo piloto (PC10%+VIO). Então foram selecionados 20 pacientes, e a seleção das hemi-arcadas e tratamentos foram realizados por sorteio. O gel clareador foi aplicado por 8 horas diárias pelo paciente e o mesmo retornou ao consultório 2 vezes/semana durante 3 semanas para irradiação com a VIO por 30 minutos em cada sessão clínica. Os dados foram submetidos à testes estatísticos ANOVA 2 fatores com medidas repetidas e observou-se que o hemi-arco que recebeu a associação apresentou resultados favoráveis na alteração de cor, porém houve um aumento da sensibilidade dentário, mesmo após o término do tratamento (14 dias após). Conclui-se que o uso da VIO com géis menos concentrados apresentam eficácia satisfatória, porém deve-se ser utilizado com cautela para não causar efeitos colaterais(AU)

Researchers have proposed tooth whitening only with the irradiation of violet light (VIO), without the need for whitening gel. Therefore, the objective of this study was to evaluate in vitro and in vivo this new treatment associated with different concentrations of hydrogen peroxide (PH) for its bleaching efficacy and possible adverse effects. For the in vitro study, 567 (n = 67) teeth were selected and divided into 9 groups: No Gel (SG) -Without Light (SL), PH17.5% -SL, PH35% - SL, SG-LED / Laser (LED), PH17.5% -LED, PH35% -LED, SG-VIO, PH17.5% - VIO, and PH35% -VIO. The application of the gels followed the manufacturer's recommendations. The LED was applied 3 times 3 minutes, the VIO was applied 3 times 7 minutes. After the bleaching procedures, superficial chromatic alteration and fluorescence intensity analyzes were performed (n = 10), considering 5 analysis times (initial T0, T1-1st session, T2-2nd session, T3-3th session, T4- 14 days later), depth color change (n = 15), hydraulic conductance (n = 10), PH diffusion (n = 10), cell viability (n = 8) and intrapulp temperature variation (n = 10). Data were submitted to appropriate statistical tests for each type of analysis. VIO when used alone provided superficial and deep color changes, but its effect was statistically smaller than that provided by the whitening gel. In fluorescence, the T1 and T3 of PH35% -SL were different. PH diffusion and dental permeability, the PH35% groups presented the highest values, being potentiated when associated with LED / Laser. In cell metabolism, the PH35% groups presented the lowest values, and the isolated VIO increased intrapulp temperature and decreased cell viability. For the in vivo part of the study, 6 patients were initially selected and assigned to 3 treatments for the pilot study (n = 2): 10% Carbamide Peroxide (PC) + IVI, IVI and PH17.5% + IVI. Only the right side associated the irradiation with VIO with whitening gel, while the left side received only the application of the whitening gel. Nine clinical sessions were held, and in each session, 20 1-minute irradiations were performed at 30-second intervals. Patients receiving PC10% + VIO presented greater difference between hemi-arches, with positive results for the side that received the association with light, but it was found greater tooth sensitivity in this association. In the second study, the treatment with the largest difference observed in the pilot study (PC10% + VIO) was selected. Then, 20 patients were selected, and the selection of hemi-arches and treatments were performed by lot. The whitening gel was applied for 8 hours daily by the patient and he returned to the office 2 times / week for 3 weeks for IV irradiation for 30 minutes in each clinical session. Data were submitted to repeated-measures 2-way ANOVA statistical tests and it was observed that the hemi-arch that received the association showed favorable results in color change, but there was an increase in tooth sensitivity even after the end of treatment (14 days after). It is concluded that the use of IVC with less concentrated gels is satisfactory, but should be used with caution not to cause side effects(AU)

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.

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

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. 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. 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. 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.

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.

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.

Effect of Dental Pigmentation Intensity on the Transenamel and Transdentinal Penetration of Hydrogen Peroxide.

Abastract This study aimed to evaluate the transenamel and transdentinal penetration of hydrogen peroxide (H202) applied to bovine teeth pigmented with black tea at different intensities. The following groups were formed DW: immersion in distilled water; BT100: immersion in an infusion of 1.6 g of black tea per 100 mL distilled water; BT10: immersion in an infusion of 1.6 g black tea per 10 mL distilled water. All groups were immersed for 6 days. To quantify the penetration of H202, the specimens were placed in artificial pulp chambers (APCs) and subjected to bleaching treatment with 38% H2O2 once per week for 3 weeks. After bleaching treatment, the acetate buffer solution of APCs with peroxidase enzyme was evaluated in a reflection spectrophotometer. The transenamel and transdentinal penetration of H2O2 and the L* values obtained at T1, T2 and T3 were subjected to Kruskal-Wallis and Friedman statistical tests. At T1, the H2O2 diffusion in DW was higher than that in BT100 and BT10. At the other evaluation times, the penetration values in BT100 and BT10 increased and remained similar. The L* values increased significantly in all groups at T1. At T2, the L* values were higher in DW, while the values in BT100 and BT10 were similar to each other. At the end of the experiment, BT10 showed the lowest L* values. The pigmentation level did not affect the penetration of H2O2 through the enamel and dentin and the bleaching agent effectively changed the color of the teeth.

Effect of Dental Pigmentation Intensity on the Transenamel and Transdentinal Penetration of Hydrogen Peroxide

Abastract This study aimed to evaluate the transenamel and transdentinal penetration of hydrogen peroxide (H202) applied to bovine teeth pigmented with black tea at different intensities. The following groups were formed DW: immersion in distilled water; BT100: immersion in an infusion of 1.6 g of black tea per 100 mL distilled water; BT10: immersion in an infusion of 1.6 g black tea per 10 mL distilled water. All groups were immersed for 6 days. To quantify the penetration of H202, the specimens were placed in artificial pulp chambers (APCs) and subjected to bleaching treatment with 38% H2O2 once per week for 3 weeks. After bleaching treatment, the acetate buffer solution of APCs with peroxidase enzyme was evaluated in a reflection spectrophotometer. The transenamel and transdentinal penetration of H2O2 and the L* values obtained at T1, T2 and T3 were subjected to Kruskal-Wallis and Friedman statistical tests. At T1, the H2O2 diffusion in DW was higher than that in BT100 and BT10. At the other evaluation times, the penetration values in BT100 and BT10 increased and remained similar. The L* values increased significantly in all groups at T1. At T2, the L* values were higher in DW, while the values in BT100 and BT10 were similar to each other. At the end of the experiment, BT10 showed the lowest L* values. The pigmentation level did not affect the penetration of H2O2 through the enamel and dentin and the bleaching agent effectively changed the color of the teeth.

Resumo Este estudo teve como objetivo avaliar a penetração trans-amelodentinária do peróxido de hidrogênio (H2O2) aplicados em dentes bovinos pigmentados com chá preto em diferentes intensidades. Divisão dos grupos: AD em água destilada; CP100 em uma infusão de 1,6 g de chá preto para 100 mL de água destilada; CP10 em uma infusão de 1,6 g de chá preto para 10 mL de água destilada. Todos os grupos foram imersos por 6 dias. Para quantificar a penetração de H2O2, as amostras foram colocadas em câmaras pulpares artificiais (CPAs) e submetidas a um tratamento clareador com PH a 38%, uma vez por semana durante 3 semanas. Após o tratamento clareador, a solução tampão de acetato das CPAs com a enzima da peroxidase, foi avaliada num espectrofotômetro de reflexão. A penetração trans-amelodentinária de PH e os valores de L* obtidos em T1, T2 e T3 foram submetidos ao teste estatístico de Kruskal-Wallis e Friedman. Em T1, a difusão de H2O2 no AD foi mais elevada do que em CP100 e CP10. Nos outros tempos de avaliação, os valores de penetração no CP100 e CP10 aumentaram e permaneceram semelhantes. Os valores L* aumentaram significativamente em todos os grupos no T1. No T2, os valores L* foram maiores no AD e os valores em CP100 e CP10 foram semelhantes entre si. No último tempo, o CP10 apresentou os menores valores de L*. Diferentes níveis de pigmentação não afetaram a penetração de H2O2 através do esmalte e dentina e o agente de clareador foi eficaz na alteração cromática.

Penetration Capacity, Color Alteration and Biological Response of Two In-office Bleaching Protocols.

Hydrogen peroxide (H2O2) penetrates into the dental hard tissues causing color alteration but also alterations in pulpal tissues. Hard-tissue penetration, color alteration and the pulp response alterations were evaluated for two in-office bleaching protocols with H2O2. For trans-enamel/dentin penetration and color alteration, discs of bovine teeth were attached to an artificial pulp chamber and bleached according to the groups: BLU (20% H2O2 - 1x50 min, Whiteness HP Blue); MAX (35% H2O2 - 3x15 min, Whiteness HP Maxx); Control (1x50 min, placebo). Trans-enamel/dentin penetration was quantified based on the reaction of H2O2 with leucocrystal violet and the color analyzed by CIELab System. Twenty Wistar rats were divided into two groups (BLU and MAX) and their maxillary right molars were treated according to the same protocols of the in vitro study; the maxillary left molars were used as controls. After 2 days, the animals were killed and their maxillae were examined by light microscopy. The inflammation of pulp tissue was scored according to the inflammatory infiltrate (1, absent; 2, mild; 3, moderate; 4, severe/necrosis). Data were analyzed by statistical tests (α=0.05). MAX showed higher trans-enamel/dentinal penetration of H2O2 (p<0.05). The color alteration was similar for both groups (p>0.05), and different when compared to Control group (p<0.05). MAX showed severe inflammation in the upper thirds of the coronal pulp, and BLU showed moderate inflammation (p<0.05). In-office bleaching protocols using lower concentrations of hydrogen peroxide should be preferred due to their reduced trans-enamel/dentinal penetration since they cause less pulp damage and provide same bleaching efficiency.

Penetration Capacity, Color Alteration and Biological Response of Two In-office Bleaching Protocols

Abstract Hydrogen peroxide (H2O2) penetrates into the dental hard tissues causing color alteration but also alterations in pulpal tissues. Hard-tissue penetration, color alteration and the pulp response alterations were evaluated for two in-office bleaching protocols with H2O2. For trans-enamel/dentin penetration and color alteration, discs of bovine teeth were attached to an artificial pulp chamber and bleached according to the groups: BLU (20% H2O2 - 1x50 min, Whiteness HP Blue); MAX (35% H2O2 - 3x15 min, Whiteness HP Maxx); Control (1x50 min, placebo). Trans-enamel/dentin penetration was quantified based on the reaction of H2O2 with leucocrystal violet and the color analyzed by CIELab System. Twenty Wistar rats were divided into two groups (BLU and MAX) and their maxillary right molars were treated according to the same protocols of the in vitro study; the maxillary left molars were used as controls. After 2 days, the animals were killed and their maxillae were examined by light microscopy. The inflammation of pulp tissue was scored according to the inflammatory infiltrate (1, absent; 2, mild; 3, moderate; 4, severe/necrosis). Data were analyzed by statistical tests (α=0.05). MAX showed higher trans-enamel/dentinal penetration of H2O2 (p<0.05). The color alteration was similar for both groups (p>0.05), and different when compared to Control group (p<0.05). MAX showed severe inflammation in the upper thirds of the coronal pulp, and BLU showed moderate inflammation (p<0.05). In-office bleaching protocols using lower concentrations of hydrogen peroxide should be preferred due to their reduced trans-enamel/dentinal penetration since they cause less pulp damage and provide same bleaching efficiency.

Resumo O peróxido de hidrogênio (H2O2) é capaz de penetrar pelos tecidos dentários, alterando a coloração destes, e causar danos a polpa. Este estudo avaliou a penetração por esmalte e dentina, a alteração de cor e a reposta tecidual pulpar, provocadas pelo uso de duas concentrações de H2O2 em protocolos de clareação dentária de consultório. Discos de dentes bovinos em câmaras pulpares artificiais receberam géis clareadores para avaliação da penetração por esmalte e dentina e da alteração de cor, formando os grupos: BLU (H2O2 20% - 1x50 min, Whiteness HP Blue); MAX (H2O2 35% - 3x15 min, Whiteness HP Maxx); e Controle (gel placebo - 1x50 min). A penetração por esmalte e dentina foi quantificada baseada na reação do H2O2 com o corante violeta leucocristal, e a alteração de cor foi analisada pelo sistema CIELab. Vinte ratos Wistar foram divididos em dois grupos (BLU e MAX), e tiveram os molares direito superiores tratados com os mesmos protocolos do estudo in vitro; os molares superiores do lado esquerdo serviram de controle. Após 2 dias, os animais foram eutanasiados e as maxilas examinadas por microscopia de luz. Foram atribuídos escores ao infiltrado inflamatório (1, ausente; 2, leve; 3, moderado; 4 severo ou necrose). Os dados foram submetidos a testes estatísticos (=0,05). O grupo MAX apresentou maior penetração de H2O2 por esmalte e dentina (p<0,05). A alteração de cor foi semelhante nos grupos clareados (p>0,05), mas diferente quando comparados grupos clareados com controle (p<0,05). MAX apresentou inflamação severa nos terços superiores da polpa coronária, e BLU apresentou inflamação moderada (p<0,05). Assim, protocolo para procedimento clareador de consultório utilizando baixas concentrações de H2O2 deve ser de escolha na clínica, por reduzir a penetração por esmalte e dentina, causando menos danos à polpa, e proporcionar mesma eficiência clareadora.