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

Hábitos tabágicos : conhecimentos e consumo dos adolescentes

Enquadramento: No adolescente ocorrem metamorfoses físicas, psicológicas, comportamentais e sociais, sentindo-se mais autónomo, integrado e independente. Reproduzindo o mundo dos adultos, espelha no grupo de pares hábitos de consumo de substâncias psicoativas, mormente o tabaco, amplamente aceite como a causa principal de morbilidade e de mortalidade evitável no mundo, com consequências diretas e indiretas na saúde, a curto e longo prazo. Objetivos: Identificar as variáveis sociodemográficas e de contexto familiar; estimar o impacto das variáveis de contexto escolar e estilos de vida; analisar a relação entre as variáveis psicológicas (autoestima, autoconceito); identificar as atitudes que influem os conhecimentos e o consumo de tabaco. Métodos: Estudo quantitativo, descritivo, correlacional, analítico e transversal, numa amostra de 971 adolescentes, aplicou-se o questionário sociodemográfico, de contexto escolar e estilos de vida; a Escala de Autoestima de Rosenberg (Romano, Negreiro & Martins, 2007); o Inventário Clínico de Autoconceito (Vaz Serra, 1984) e a Escala do Consumo de Tabaco (Precioso, 2007). Resultados: Os 971 inquiridos são adolescentes entre os 14 e 21 anos, 43.4% têm idade inferior a 17 anos, são maioritariamente rapazes (50.8%), residem predominantemente em meio rural (66.4%) e coabitam com os pais (77.3%). Cerca de 39.0% frequentam o 10.º ano, revelam bom autoconceito (45.3%) e elevada autoestima (47.4%). A maioria (62.0%) é ou já foi consumidora de tabaco (63.0% raparigas vs 60.6% rapazes); fumaram o primeiro cigarro, em média, aos 13,8 anos, sendo os rapazes mais precoces (≤ 13 anos) que as raparigas ( ≥15 anos). O primeiro cigarro foi obtido na escola (35.5% raparigas vs rapazes 39.1%), principal local de oferta (56.8%) e a compra ocorreu na tabacaria ou no café (60.0%). Dos inquiridos, 17,7% (13.0% raparigas vs 22.0% rapazes) são fumadores diários, consumindo até sete cigarros (60.9% rapazes vs 58.3% raparigas). Como razão principal para fumar o primeiro cigarro, 74.3% apontam “Querer saber como era”. Conclusão: O tabagismo é um fenómeno complexo e globalizante com repercussões tanto na saúde individual dos fumadores como na saúde pública, pelo que permanece a urgência de implementação de políticas de educação para a saúde, com ações de sensibilização, prevenção e promoção de mudanças comportamentais e atitudinais, preditoras de estilos de vida saudável.ABSTRACT Framework: During adolescence, the teenager suffers metamorphosis at a physical, psychological, behavioral and social level, therefore feeling more autonomous, integrated and independent. While mimicking adult behavior among its peers, he/she tends to engage in the consumption of psychoactive substances, namely tobacco, widely accepted as the leading cause of morbidity as well as mortality avoidable worldwide, with both direct and indirect consequences in short and long term health. Goals: Identify the sociodemographic and familiar context variables; assess the impact of the school context and lifestyle variables; analyze the relation between the psychological variables (self-esteem, self-concept) and identify the attitudes, which influences the knowledge as well as the tobacco consumption. Methods: Quantitative, correlational, analytical and transversal study, within a sample of 971 adolescents was applied the sociodemographic questionnaire of school context and lifestyle; Self-Esteem Rosenberg Scale (Romano, Negreiro & Martins, 2007); Self-Concept Clinical Inventory (Vaz Serra, 1984) and the Tobacco Consumption Scale (Precioso, 2007). Results: The 971 inquired were adolescents from 14 to 21 years old, 43.3% were under 17 years old, mainly males (50.8%), living in the countryside (66.4%) with their parents (77.3%). About 39.0% are in the 10th grade, reveal good self-concept (45.3%) and high selfesteem (47.4%). The majority (62.0%) is or has been a tobacco consumer (63.0% girls vs 60.6% boys); they smoked their first cigarette with an average age of 13.8 years old, whilst male are more premature (≤13 years old) than female (≥15 years old). Their first smoke was in school (35.5% girls vs 39.1% boys), which is the main place of offering (56.8%) and they buy them in tobacco or coffee shops (60.0%) From the surveyed, 17.7% (13.0% girls vs 22.0% boys) are daily smokers, some smoking up to 7 cigarettes per day. The main reason to smoke their first cigarette is “Wishing to know how it felt like” (74.3%). Conclusion: Smoking is both a complex and global phenomenon with repercussions not only in individual health, but also in public health. The urgency to implement politics for health education, through awareness raising actions, prevention and promotion of behavioral changes as well as attitude, predictive of a healthy lifestyle

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.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°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

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: "Papacarie", 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 (alpha=0.05) were performed, except for DIAGNOdent, which did not detect the presence of caries. Results for removed dentin thickness were: "Papacarie" (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: "Papacarie" (42.2 +/- 10.5; bc), Caries-detector dye (44.6 +/- 11.8; bc), Tactile method (24.3 +/- 9.0; d). Conclusions: DIAGNOdent did not detect the presence of carious tissue; Tactile method and "Papacarie" resulted in the least and the most dentinal thickness removal, respectively; Tactile method differed significantly from "Papacarie" and Caries-detector dye in terms of the remaining dentin microhardness, and Tactile method was the one which presented the lowest microhardness values

Transdentinal protective role of sodium ascorbate against the cytopathic effects of H(2)O(2) released from bleaching agents

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.1044e70e7

Penetration of 38% hydrogen peroxide into the pulp chamber in bovine and human teeth submitted to office bleach technique

This study evaluated the pulp chamber penetration of peroxide bleaching agent in human and bovine teeth after office bleach technique. All the teeth were sectioned 3 mm apical of the cement-enamel junction and were divided into 2 groups, A (70 third human molars) and B (70 bovine lateral incisors), that were subdivided into A1 and B1 restored by using composite resin, A2 and B2 by using glass ionomer cement, and A3 and B3 by using resin-modified glass ionomer cement; A4, A5, B4, and B5 were not restored. Acetate buffer was placed in the pulp chamber, and the bleaching agent was applied for 40 minutes as follows: A1-A4 and B1-B4, 38% hydrogen peroxide exposure and A5 and B5, immersion into distilled water. The buffer solution was transferred to a glass tube in which leuco crystal violet and horseradish peroxidase were added, producing a blue solution. The optical density of the blue solution was determined by spectrophotometer and converted into microgram equivalents of hydrogen peroxide. Data were submitted to analysis of variance and Dunnett, Kruskal-Wallis, and Tukey tests (5%). A higher level of hydrogen peroxide penetrated into the pulp chamber in resin-modified glass ionomer cements in bovine (0.79 +/- 0.61 mu g) and human (2.27 +/- 0.41 mu g) groups. The bleaching agent penetration into the pulp chamber was higher in human teeth for any experimental situation. The penetration of the hydrogen peroxide depends on restorative materials, and under the conditions of this study human teeth are more susceptible to penetration of bleaching agent into the pulp chamber than bovine teeth

Transdentinal Protective Role Of Sodium Ascorbate Against The Cytopathic Effects Of H2o2 Released From Bleaching Agents.

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. 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. 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. 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.109e70-