Antioxidants and biomarkers of oxidative damage in the saliva of patients with Down's syndrome.

BACKGROUND: The aim of this study was to investigate enzymatic and non-enzymatic antioxidant systems and levels of biomarker levels of oxidative damage in the saliva of patients with Down's syndrome (DS). METHODS: Saliva samples were collected from 30 patients with DS and control group (age: 14-24 years). Subsequently, the concentrations of superoxide dismutase, concentration of malondialdehyde, carbonylated proteins, uric acid, vitamin C and total protein, peroxidase activity and total antioxidant capacity were analyzed. RESULTS: Patients with DS presented significantly higher concentrations of superoxide dismutase, higher levels of malondialdehyde and salivary total protein content than controls (p<0.05). Conversely, no difference in carbonylated proteins or antioxidants (uric acid, vitamin C, peroxidase, and total antioxidant capacity) was observed between DS patients and controls (p>0.05). CONCLUSION: Patients with DS are more vulnerable to oxidative stress in saliva as indicated by the significant increase in malondialdehyde and superoxide dismutase concentrations found in this study.

Dentine microhardness after different methods for detection and removal of carious dentine tissue.

UNLABELLED: There are several methods for identifying carious dentinal tissue aiming to avoid removal of healthy dentinal tissue. OBJECTIVES: The purpose of this study was to test different methods for the detection of carious dentinal tissue regarding the amount of carious tissue removed and the remaining dentin microhardness after caries removal. MATERIAL AND METHODS: The dentin surfaces of 20 bovine teeth were exposed and half of the surface was protected with nail polish. Cariogenic challenge was performed by immersion in a demineralizing solution for 14 days. After transverse cross-section of the crown, the specimens were divided into four groups (n=10), according to the method used to identify and remove the carious tissue: "Papacárie", Caries-detector dye, DIAGNOdent and Tactile method. After caries removal, the cross-sectional surface was included in acrylic resin and polished. In a microhardness tester, the removed dentin thickness and the Vickers microhardness of the following regions were evaluated: remaining dentin after caries removal and superficial and deep healthy dentin. RESULTS: ANOVA and Tukey's test (α=0.05) were performed, except for DIAGNOdent, which did not detect the presence of caries. Results for removed dentin thickness were: "Papacárie" (424.7 ± 105.0; a), Caries-detector dye (370.5 ± 78.3; ab), Tactile method (322.8 ± 51.5; bc). Results for the remaining dentin microhardness were: "Papacárie" (42.2 ± 10.5; bc), Caries-detector dye (44.6 ± 11.8; abc), Tactile method (24.3 ± 9.0; d). CONCLUSIONS: DIAGNOdent did not detect the presence of carious tissue; Tactile method and "Papacárie" resulted in the least and the most dentinal thickness removal, respectively; Tactile method differed significantly from "Papacárie" and Caries-detector dye in terms of the remaining dentin microhardness, and Tactile method was the one which presented the lowest microhardness values.

Dentine microhardness after different methods for detection and removal of carious dentine tissue

There are several methods for identifying carious dentinal tissue aiming to avoid removal of healthy dentinal tissue. OBJECTIVES: The purpose of this study was to test different methods for the detection of carious dentinal tissue regarding the amount of carious tissue removed and the remaining dentin microhardness after caries removal. MATERIAL AND METHODS: The dentin surfaces of 20 bovine teeth were exposed and half of the surface was protected with nail polish. Cariogenic challenge was performed by immersion in a demineralizing solution for 14 days. After transverse cross-section of the crown, the specimens were divided into four groups (n=10), according to the method used to identify and remove the carious tissue: "Papacárie", Caries-detector dye, DIAGNOdent and Tactile method. After caries removal, the cross-sectional surface was included in acrylic resin and polished. In a microhardness tester, the removed dentin thickness and the Vickers microhardness of the following regions were evaluated: remaining dentin after caries removal and superficial and deep healthy dentin. RESULTS: ANOVA and Tukey's test (α=0.05) were performed, except for DIAGNOdent, which did not detect the presence of caries. Results for removed dentin thickness were: "Papacárie" (424.7±105.0; a), Caries-detector dye (370.5±78.3; ab), Tactile method (322.8±51.5; bc). Results for the remaining dentin microhardness were: "Papacárie" (42.2±10.5; bc), Caries-detector dye (44.6±11.8; abc), Tactile method (24.3±9.0; d). CONCLUSIONS: DIAGNOdent did not detect the presence of carious tissue; Tactile method and "Papacárie" resulted in the least and the most dentinal thickness removal, respectively; Tactile method differed significantly from "Papacárie" and Caries-detector dye in terms of the remaining dentin microhardness, and Tactile method was the one which presented the lowest microhardness values.

Dimensional alterations and solubility of new endodontic sealers.

This study evaluated the dimensional alterations and the solubility of two experimental endodontic sealers based on Copaifera multijuga oil-resin (Biosealer) and castor oil bean cement (Poliquil), maintained in different storage solutions. Twenty specimens (3 mm diameter and 2 mm height) of each sealer were assigned to 2 groups (n=10) according to the storage solution: simulated tissue fluid (STF) or distilled water (DW). The specimens were stored in these solutions during 90 days, being removed every 30 days for weighting. The solutions were renewed every 15 days. The results were subjected to statistical analysis by Dunn's and Mann-Whitney tests (a=0.05). The solubility of Poliquil was higher in STF (38.4 ± 36.0) than in DW (28.4 ± 15.0), while Biosealer showed higher solubility in DW (34.61 ± 6.0) than in STF (18.59 ± 8.0). The storage solution influenced the behavior of sealers in relation to the weight variation (p=0.0001). Poliquil presented higher variation of weight independent of the solution (p=0.239). Biosealer also presented higher variation of weight regardless of the solution (p=0.0001). The solubility of Biosealer was different from that of Poliquil, but both sealers showed low solubility in STF. Under the tested conditions, neither of the materials were according to the ADA'S specification.

Peroxide penetration from the pulp chamber to the external root surface after internal bleaching.

PURPOSE: To quantify the amount of peroxide penetration from the pulp chamber to the external surface of teeth during the walking bleaching technique. METHODS: Seventy-two bovine lateral incisors were randomly divided over five experimental groups and one control (n = 12 per group): (1) 35% hydrogen peroxide (HP); (2) 35% carbamide peroxide (CP); (3) sodium perborate (SP); (4) (HP+SP); (5) (CP+SP) and (6) Control (CG), deionized water. All groups were treated according to the walking bleach technique. After 7 days at 37 degrees C in an acetate buffer solution, 100 microl violet leukocrystal coloring and 50 microl peroxidase was added, producing a blue stain that could be measured in a spectrophotometer and then converted into peroxide microg/ml. RESULTS: G5 exhibited the greatest penetration, while G2 and G3 produced the lowest values. All bleaching agents penetrated from the pulp chamber to the external root surface. There was a direct correlation between the presence of oxidative agents and penetration potential. Sodium perborate in distilled water was less oxidative and appeared to be the least aggressive bleaching agent.

Transdentinal protective role of sodium ascorbate against the cytopathic effects of H2O2 released from bleaching agents.

OBJECTIVES: The objectives of this study were to evaluate the transdentinal cytotoxicity of 10% and 16% carbamide peroxide gel (CP), as well as the ability of the antioxidant, 10% sodium ascorbate (SA), to protect the odontoblasts in culture. STUDY DESIGN: Human dentin discs of 0.5-mm thickness were obtained and were placed into artificial pulp chambers. MDPC-23 odontoblastlike cells were seeded on pulp surface of the discs and the following groups were established: G1-No Treatment (control), G2-10% SA/6hs, G3-10%/CP6hs, G4-10%SA/6hs+10%CP/6hs, G5-16%CP/6hs, and G6-10%SA/6hs+16%CP/6hs. The cell viability was measured by the MTT assay. RESULTS: In groups where 16% CP was used, decreased cell viability was observed. Conversely, the application of 10% SA on the dentin discs, before the use of the CP, reduced the cytotoxic effects of these products on cells. CONCLUSIONS: The 16% CP cause a significant decrease in MDPC-23 cell viability and 10% SA was able to partially prevent the toxic effects of CP.

Dimensional alterations and solubility of new endodontic sealers

This study evaluated the dimensional alterations and the solubility of two experimental endodontic sealers based on Copaifera multijuga oil-resin (Biosealer) and castor oil bean cement (Poliquil), maintained in different storage solutions. Twenty specimens (3 mm diameter and 2 mm height) of each sealer were assigned to 2 groups (n=10) according to the storage solution: simulated tissue fluid (STF) or distilled water (DW). The specimens were stored in these solutions during 90 days, being removed every 30 days for weighting. The solutions were renewed every 15 days. The results were subjected to statistical analysis by Dunn's and Mann-Whitney tests (a=0.05). The solubility of Poliquil was higher in STF (38.4 ± 36.0) than in DW (28.4 ± 15.0), while Biosealer showed higher solubility in DW (34.61 ± 6.0) than in STF (18.59 ± 8.0). The storage solution influenced the behavior of sealers in relation to the weight variation (p=0.0001). Poliquil presented higher variation of weight independent of the solution (p=0.239). Biosealer also presented higher variation of weight regardless of the solution (p=0.0001). The solubility of Biosealer was different from that of Poliquil, but both sealers showed low solubility in STF. Under the tested conditions, neither of the materials were according to the ADA'S specification.

O presente estudo avaliou a alteração dimensional e solubilidade de 2 cimentos experimentais (à base de resina do óleo de Copaíba - Biosealer e cimento do polímero da mamona - Poliquil), mantidos em diferentes meios de armazenamento. Foram confeccionados 20 espécimes de cada cimento com 3 mm de diâmetro e 2 mm de altura os quais foram divididos em 2 grupos (n=10) de acordo com o meio de armazenamento (fluido tissular simulado ou água destilada). Os espécimes foram atidos nas soluções durante 90 dias, sendo removidos a cada 30 dias para pesagem das amostras, no entanto as soluções foram trocadas a cada 15 dias. Os resultados foram submetidos aos testes de Dunn (5 por cento) e Mann-Whitney. Os meios de armazenamento causaram influência no comportamento dos cimentos em relação ao peso (p=0,0001). Poliquil apresentou alta variação de peso independente da solução (p=0,239). Biosealer também apresentou alta variação de peso independente da solução (p=0,0001). A solubilidade do Biosealer foi diferente do Poliquil, entretanto, ambos cimentos mostraram baixa solubilidade no fluido tissular simulado. Nas condições do experimento, nenhum cimento está de acordo com a especificação da ADA.

Smear layer removal by auxiliary chemical substances in biomechanical preparation: a scanning electron microscope study.

The aim of this study was to assess, by scanning electron microscopy analysis, the cleaning ability of irrigants and auxiliary chemical substances in biomechanical preparation. Thirty-two single-rooted human teeth were subjected to standardized root canal instrumentation with different irrigants (n = 8): group 1, 2.5% NaOCl + 17% ethylenediaminetetraacetic acid (EDTA); group 2, 2% chlorhexidine gel + 17% EDTA; group 3, Canal Plus + 2.5% NaOCl; group 4, saline + 17% EDTA. After instrumentation, the teeth were prepared for scanning electron microscopy analysis (2000x) to evaluate the cleaning of cervical, middle, and apical thirds. The area analyzed was quantified according to the percentage of open tubules, and data were statistically analyzed by analysis of variance and Tukey tests (P = .05). The results showed statistically significant difference with higher quantity of open tubules in groups 1 and 3. In all groups, the cleaning obtained on the cervical third was better than that obtained on the middle and apical thirds, with statistically significant difference in the chlorhexidine group. Irrigation with Canal Plus in combination with NaOCl and NaOCl followed by EDTA produced greater cleaning of the root canal walls.

The effect of endodontic materials on the optical density of dyes used in marginal leakage studies.

The aim of this study was to determine the effect of the exposure of different endodontic materials to different dye solutions by evaluating the optical density of the dye solutions. Seventy-five plastic tubes were filled with one of the following materials: AH Plus, Sealapex, Portland cement, MTA (Angelus and Pro Root) and fifteen control plastic tubes were not. Each specimen of material and control was immersed in a container with 1 ml of each dye solution. A 0.1 ml-dye solution aliquote was removed before immersion and after 12, 24, 48 and 72 hours of each specimen immersion to record its optical density (OD) in a spectrophotometer. Statistical analysis was performed with ANOVA and Tukey tests (5%). No significant difference was found among any of the solution OD values for AH Plus cement. Portland cement promoted different OD values after 12 hours of immersion. MTA-Angelus cement presented different OD values only for 2% rhodamine B and the MTA-Pro Root cement presented different OD values in all 2% rhodamine B samples. Sealapex cement promoted a reduction in the India Ink OD values. Dye evaluation through OD seems to be an interesting method to select the best dye solution to use in a given marginal leakage study.

The effect of endodontic materials on the optical density of dyes used in marginal leakage studies

The aim of this study was to determine the effect of the exposure of different endodontic materials to different dye solutions by evaluating the optical density of the dye solutions. Seventy-five plastic tubes were filled with one of the following materials: AH Plus, Sealapex, Portland cement, MTA (Angelus and Pro Root) and fifteen control plastic tubes were not. Each specimen of material and control was immersed in a container with 1 ml of each dye solution. A 0.1 ml-dye solution aliquote was removed before immersion and after 12, 24, 48 and 72 hours of each specimen immersion to record its optical density (OD) in a spectrophotometer. Statistical analysis was performed with ANOVA and Tukey tests (5 percent). No significant difference was found among any of the solution OD values for AH Plus cement. Portland cement promoted different OD values after 12 hours of immersion. MTA-Angelus cement presented different OD values only for 2 percent rhodamine B and the MTA-Pro Root cement presented different OD values in all 2 percent rhodamine B samples. Sealapex cement promoted a reduction in the India Ink OD values. Dye evaluation through OD seems to be an interesting method to select the best dye solution to use in a given marginal leakage study.

Avaliação do contato de dois materiais retrobturadores na densidade óptica decorantes tamponados e não tamponados / Evaluation of the contact of two retrofilling materials on optical density of buffered and unbuffered dyes

O objetivo deste trabalho foi avaliar a densidade óptica das soluções corantes azul de metileno 2% tamponada e nãotamponada, rodamina B 2% tamponada e não tamponada, antes e após a imersão de dois materiais retrobturadores por diferentes períodos de tempo. As soluções corantes, sem a imersão dos espécimes, foram analisadas nos períodos de 0,12, 24, 48 e 72 horas. Foram preparados oitenta espécimes de cimento Sealer 26 e oitenta de cimento de Portland, os quais foram imersos em 0,7 ml de cada uma das soluções corantes e avaliados nos períodos de tempo de 12, 24, 48 e 72 horas. A densidade óptica foi avaliada em espectrofotômetro ajustado em 596nm para o azul de metileno e 566nmpara a rodamina B. Os dados obtidos foram analisados através dos testes ANOVA (3 fatores) e Tukey 5%. Os resultados mostraram que houve diferença estatisticamente significativa nos valores da densidade óptica do azul de metileno 2% tamponado após a imersão do Sealer 26 nos períodos de 24, 48 e 72 horas em relação ao tempo de 12 horas. Houve diferença estatisticamente significativa nos valores da densidade óptica da rodamina B 2% tamponada após a imersão do cimento de Portland nos períodos de 12, 24 e 48 horas em relação ao tempo de 72 horas. Pôde-se verificar que as soluções corantes não tamponadas apresentaram valores menores de densidade óptica. Dentre as soluções corantes analisadas,a rodamina B 2% tamponada apresentou comportamento mais estável quanto aos valores de densidade ópticaaté o período de avaliação de 48 horas.

Vehicle influence on calcium hydroxide pastes diffusion in human and bovine teeth.

The purpose of this study was to compare the pH and calcium ion liberation after use of calcium hydroxide pastes with different paste vehicles in human or bovine teeth. Ninety-two single-rooted human and bovine roots were used. The roots were instrumented and an external cavity preparation was performed. The roots were divided in to human and bovine groups. Each group was subdivided into four subgroups (SB) according to the vehicle:SB1, detergent; SB2, saline; SB3, polyethylenoglycol + camphorated paramonochlorophenol (Calen PMCC) and SB4, polyethylenoglycol + furacyn paramonochlorophenol (FPMC). Specimens were immersed into saline solution at 37 degrees C and after 7 and 14 days pH and calcium ion measurements were made. The results were analyzed by anova and Tukey tests (P < 0.05). There was no statistical difference between bovine and human teeth in the pH analysis (P < 0.05), but bovine teeth provided larger calcium ion liberation than human teeth. Calen PMCC was statistically more effective for pH increase and calcium ion liberation in all analyses, followed by FPMC and saline. Detergent showed the lowest pH alterations and calcium ion liberation. The period of 14 days showed more calcium ionic liberation than the 7-day period.

In vitro evaluation of apical sealing in root apex treated with demineralization agents and retrofiled with mineral trioxide aggregate through marginal dye leakage

O objetivo deste estudo foi avaliar o selamento de ápices radiculares tratados com diferentes agentes desmineralizantes e retrobturados com agregado de trióxido mineral (MTA), mediante infiltração marginal por corante. Cinqüenta e seis dentes unirradiculares humanos extraídos foram instrumentados, obturados e seccionados apicalmente. Os preparos cavitários apicais foram confeccionados com pontas ultra-sônicas e os agentes desmineralizantes foram aplicados previamente à retrobturação com Pro Root MTA. Os espécimes foram divididos aleatoriamente em 4 grupos (n=14): grupo 1 (sem agente desmineralizante); grupo 2 (ácido fosfórico 35% durante 15 s); grupo 3 (solução de EDTA 17%, pH 7, durante 3 min); grupo 4 (gel de EDTA 24%, pH 7, durante 4 min). A extensão da infiltração de corante (rodamina B 2% a 37°C, por 24 h) foi avaliada em milímetros utilizando-se um estereomicroscópio. Os resultados foram analisados estatisticamente por meio de análise de variância a um critério e do teste Tukey com nível de significância de 5%. Dentre os grupos experimentais, a menor extensão de infiltração do corante foi verificada no grupo 1 (1,89 mm), seguido pelos grupos 2 (2,18 mm), 4 (2,54 mm) e 3 (2,64 mm). Não houve diferenças estatisticamente significante (p>0.05) na infiltração marginal pelo corante entre os grupos 1, 2 e 4 e os grupos 2, 3 e 4. Com base nos resultados obtidos, pode-se concluir que a aplicação de agentes desmineralizantes não pode ser recomendada quando da utilização do MTA em cirurgias parendodônticas.

In vitro evaluation of apical sealing in root apex treated with demineralization agents and retrofiled with mineral trioxide aggregate through marginal dye leakage.

The purpose of this study was to evaluate the apical seal in root apex treated with different demineralization agents and retrofilled with mineral trioxide aggregate (MTA) using marginal dye leakage. Fifty-six, human single-rooted teeth were instrumented, filled, resected and had retrofilling cavities prepared with ultrasonic tips. Demineralizing agents were applied before the apical cavities were retrofilled with Pro Root MTA. The specimens were assigned to 4 groups (n=14), as follows: group 1 (no demineralizing agent); group 2 (35% phosphoric acid, for 15 s); group 3 (17% EDTA solution, pH 7, for 3 min); and group 4 (24% EDTA gel, pH 7, for 4 min). The extension of dye (2% rhodamine B, at 37 degrees C, for 24 h) penetration was measured in millimeters using a stereomicroscope. Results were statistically analyzed by ANOVA and Tukey's test at 5% significance level. Among the experimental groups, the least extension of dye penetration was observed in group 1 (1.89 mm), followed by groups 2 (2.18 mm), 4 (2.54 mm) and 3 (2.64 mm). No statistically significant differences (p<0.05) were found in marginal microleakage among groups 1, 2 and 4 and groups 2, 3 and 4. Based on the results obtained in this study, it may be concluded that the application of demineralizing agents cannot be recommended when MTA is used in periradicular surgeries.

Avaliação do pH e liberação de íons cálcio, na utilização intracanal de pastas à base de hidróxido de cálcio / Diffusion of hydroxyl ion and calcium ion through the dentin, from calcium hydroxide intracanal pastes

O propósito deste trabalho foi o de avaliar in vitro as alterações do pH e liberação de íons cálcio, após a utilização intracanal, de pastas de hidróxido de cálcio com diferentes veículos. Nesse estudo foram utilizados 46 dentes unirradiculados bovinos, que tiveram suas coroas removidas, após isso realizou-se o preparo biomecânico 1 mm aquém do forame com irrigação de hipoclorito de sódio 2,5 por cento, seguido de irrigação final com EDTA. No terço médio de cada espécime na superfície radicular externa, foi realizado um preparo com 4 mm de comprimento X 2 mm de largura e 1 mm de profundidade. Os canais foram preenchidos com pastas de hidróxido de cálcio e para isso foram divididos em grupos de acordo com o veículo utilizado, G1: detergente; G2: solução salina; G3: polietilenoglicol 400 + paramonoclorofenol furacinado (PMCF). As raízes foram impermeabilizadas externamente, exceto na área da cavidade, imersas individualmente em frascos contendo 4ml de solução salina fisiológica e, mantidas à 37°C. As mensurações de pH e liberação de cálcio foram feitas aos sete e 14 dias. O Calen PMCC foi estatisticamente superior em todas as análises, seguido pelo PMCF e solução salina, que se equivaleram e por último o detergente que foi estatisticamente inferior aos demais grupos. O período de 14 dias mostrou maior aumento na liberação iônica