Influence of intrapulpal pressure simulation on the bond strength of adhesive systems to dentin

The purpose of this study was to evaluate the influence of intrapulpal pressure simulation on the bonding effectiveness of etch & rinse and self-etch adhesives to dentin. Eighty sound human molars were distributed into eight groups, according to the permeability level of each sample, measured by an apparatus to assess hydraulic conductance (Lp). Thus, a similar mean permeability was achieved in each group. Three etch & rinse adhesives (Prime & Bond NT - PB, Single Bond -SB, and Excite - EX) and one self-etch system (Clearfil SE Bond - SE) were employed, varying the presence or absence of an intrapulpal pressure (IPP) simulation of 15 cmH2O. After adhesive and restorative procedures were carried out, the samples were stored in distilled water for 24 hours at 37°C, and taken for tensile bond strength (TBS) testing. Fracture analysis was performed using a light microscope at 40 X magnification. The data, obtained in MPa, were then submitted to the Kruskal-Wallis test ( a = 0.05). The results revealed that the TBS of SB and EX was significantly reduced under IPP simulation, differing from the TBS of PB and SE. Moreover, SE obtained the highest bond strength values in the presence of IPP. It could be concluded that IPP simulation can influence the bond strength of certain adhesive systems to dentin and should be considered when in vitro studies are conducted

Microleakage in class V cavities restored with esthetic materials, using different restorative techniques

Este trabalho teve como objetivo avaliar, in vitro, a infiltração marginal em restaurações de classe V, executadas com resina composta (RC), cimento de ionômero de vidro resino-modificado (CIVRM) e compômeros, por meio de diferentes técnicas restauradoras, e submetidas à ciclagem mecânica e térmica. Trinta e seis molares humanos íntegros receberam 72 preparos de classe V nas faces vestibular e lingual. A margem oclusal foi localizada em esmalte; a margem gengival, em dentina. Os dentes foram divididos em nove grupos de oito espécimes cada. As cavidades foram restauradas de acordo com as diferentes técnicas. Nos grupos 1, 2, 4 e 5, não foi feito condicionamento ácido. Após 24 horas em água a 37°C, as amostras sofreram ciclagem mecânica e térmica, imersão em rodamina B e secção no sentido vestíbulo-lingual. O grau de penetração variou de zero (infiltração) a 3 (infiltração máxima). O teste Kruskal-Wallis revelou diferenças estatísticas significantes entre as técnicas restauradoras (p < 0,05). Sem o condicionamento ácido, os compômeros apresentaram a maior infiltração nas duas margens, oclusal e gengival. A RC, na margem gengival, exibiu menor infiltração que os compômeros e o CIVRM. A retenção adicional e o condicionamento ácido + adesivo foram ambos capazes de reduzir a infiltração nas margens gengival e oclusal das restaurações de compômeros.The purpose of this study was to compare the microleakage of class V cavities restored with composite resin (CR), resin-modified glass ionomer cement (RMGIC) and polyacid-modified resin composite (PAMRC), using different clinical procedures. Thirty-six noncarious human molars were used in this study. A class V cavity, measuring approximately 3 mm x 4 mm x 2 mm, was prepared in each tooth in both buccal and lingual aspects, with a diamond bur (number 1,093) at high speed, with coolant water spray. The occlusal margin was located on enamel and the gingival margin was located on dentin. The teeth were divided into 9 groups with 8 specimens each. The cavities were restored according to different techniques. The specimens from groups 1, 2, 4 and 5 did not receive acid etching. The samples were stored in water at 37°C for 24 hours, subjected to occlusal load, thermocycled and immersed in rhodamine B. The restorations were then washed and sectioned in buccolingual direction. The depth of dye penetration was scored from zero (no leakage) to 3 (maximum leakage). The Kruskal-Wallis test revealed statistically significant differences between the materials (p < 0.05). PAMRC used without acid etching showed the greatest score of leakage in both margins. In the gingival margin, CR showed scores of leakage lower than those of PAMRC and RMGIC. Additional retentions and acid etching were able to decrease microleakage in PAMRC restorations in both gingival and occlusal margins

Importância do tempo de espera pós-tratamento clareador no selamento marginal de restaurações classe V em resina composta

The aim of this study was to evaluate changes in mineral content of bleached enamel and the infl uence of post-bleaching time interval on the marginal seal of class V composite restorations. Forty bovine incisors were restored using Magic Bond adhesive and Fill NT Premium composite according to the manufacturer’s instructions. The teeth were randomly divided into 4 experimental groups (n = 10): G1, not bleached (control); G2, bleached and immediately restored; G3, bleached and restored after 7 days; G4, bleached and restored after 14 days. The mineral content was evaluated by QLF (quantitative light-induced fl uorescence). The microleakeage scores were analyzed by 3 calibrated examiners. There was no statistical difference between the groups regarding change of the bleached mineral substrate (repeated measures ANOVA, p = 0.2130) and the microleakage scores (Friedman, p = 0.2551). It was concluded that the bleaching protocol used is safe because it does not cause mineral changes in the bleached enamel, and that the post-bleaching time interval observed before performing adhesive procedures did not affect the marginal seal of composite resin restorations.O objetivo deste estudo foi avaliar o conteúdo mineral do esmalte submetido ao clareamento dental e a influência do tempo de espera após o tratamento clareador no selamento marginal de restaurações classe V em resina composta. Neste estudo, a variável de resposta selamento marginal foi avaliada por metodologia de microinfiltração, segundo o fator de variação tempo de espera para o procedimento restaurador, imediatamente após, e 7 e 14 dias após o tratamento clareador. O conteúdo mineral foi avaliado pelo método QLF (quantitative light-induced fluorescence). As unidades experimentais foram compostas por 40 coroas de incisivos bovinos que foram distribuídas entre os 4 grupos experimentais (n = 10): G1, dentes bovinos não clareados (controle); G2, dentes clareados e imediatamente restaurados; G3, dentes clareados e restaurados após 7 dias; G4, dentes clareados e restaurados após 14 dias. Os escores de infi ltração foram analisados por 3 examinadores previamente calibrados. Não foi observada diferença estatística entre os grupos com relação à alteração mineral do substrato clareado (ANOVA para mensurações repetidas, p = 0,2130) e ao grau de microinfiltração marginal (Friedman, p = 0,2551). Pôde-se concluir que o protocolo clareador utilizado é seguro por não acarretar alterações minerais do esmalte clareado, e que o tempo de espera para a realização de procedimentos adesivos não interferiu no selamento marginal de restaurações em resina composta

Avaliação da intensidade de contaminação de pontas de seringa tríplice

Effective infection control procedures to prevent cross-contamination in the dental office include care with air/water syringes. The authors had the purpose to verify the bacterial contamination of air/water syringes used in patients seen at the Restorative Dental Clinic, School of Dentistry, University of São Paulo, Brazil. Fifty disposable tips (Riskcontrol, Injecta Prod. Odontológicos) were analysed: 10, immediately after the package was opened; 10, after a single use followed by disinfection with 70% alcohol for one minute; 30, after a single use without any posterior disinfection. The samples were transported to the laboratory and, under aseptic condition, rolled and compressed on a Tryptic Soy Agar surface with 5% of defibrillated sheep blood. After a 96-hour incubation, the reading was carried out with the help of a lens. According to the manufacture&#146;s information, the disposable tips were sterilized. In all of the tips used in patients, an uncountable amount of cfu (colony formation units) was found, revealing great contamination. In the disposable tips disinfected after being used, there was small bacterial growth, but that was incompatible with cross-contamination prevention. Therefore, we conclude that disposable air/water syringes tips must have a single use.O controle de infecção cruzada em consultórios odontológicos inclui cuidados especiais com as seringas tríplices. Os autores pesquisaram a intensidade de contaminação pela microbiota bucal, de pontas de seringas tríplices usadas no atendimento a pacientes de Dentística Restauradora. Cinqüenta pontas descartáveis (Riskcontrol, Injecta Prod. Odontológicos) foram avaliadas: 10, imediatamente após a abertura da embalagem; 30, após o uso em pacientes; e 10, após o uso e a desinfecção com álcool etílico 70% P/V, friccionado por um minuto. Em câmara de fluxo laminar, as pontas foram "roladas" sobre a superfície de Tryptic Soy Agar, suplementado com 5% de sangue desfibrinado de carneiro. Após 96 horas de incubação anaeróbia, foi feita a avaliação da quantidade de unidades formadoras de colônias (ufc) desenvolvidas. Confirmando a informação do fabricante, as pontas estavam estéreis quando retiradas da embalagem. Em todas as pontas usadas em pacientes, observou-se um número incontável de ufc (maior que 300), revelando intensa contaminação. Nas pontas usadas e desinfetadas com álcool etílico 70% P/V, verificou-se apreciável redução na contagem de colônias (1 a 100 ufc), mas incompatível com a segurança biológica. Os resultados sugerem, como condição ideal, o uso de pontas descartáveis nas seringas tríplices

Avaliação da intensidade de contaminação de pontas de seringa tríplice Evaluation of the bacterial contamination of air/water syringes tips

O controle de infecção cruzada em consultórios odontológicos inclui cuidados especiais com as seringas tríplices. Os autores pesquisaram a intensidade de contaminação pela microbiota bucal, de pontas de seringas tríplices usadas no atendimento a pacientes de Dentística Restauradora. Cinqüenta pontas descartáveis (Riskcontrol, Injecta Prod. Odontológicos) foram avaliadas: 10, imediatamente após a abertura da embalagem; 30, após o uso em pacientes; e 10, após o uso e a desinfecção com álcool etílico 70% P/V, friccionado por um minuto. Em câmara de fluxo laminar, as pontas foram "roladas" sobre a superfície de Tryptic Soy Agar, suplementado com 5% de sangue desfibrinado de carneiro. Após 96 horas de incubação anaeróbia, foi feita a avaliação da quantidade de unidades formadoras de colônias (ufc) desenvolvidas. Confirmando a informação do fabricante, as pontas estavam estéreis quando retiradas da embalagem. Em todas as pontas usadas em pacientes, observou-se um número incontável de ufc (maior que 300), revelando intensa contaminação. Nas pontas usadas e desinfetadas com álcool etílico 70% P/V, verificou-se apreciável redução na contagem de colônias (1 a 100 ufc), mas incompatível com a segurança biológica. Os resultados sugerem, como condição ideal, o uso de pontas descartáveis nas seringas tríplices.<br>Effective infection control procedures to prevent cross-contamination in the dental office include care with air/water syringes. The authors had the purpose to verify the bacterial contamination of air/water syringes used in patients seen at the Restorative Dental Clinic, School of Dentistry, University of São Paulo, Brazil. Fifty disposable tips (Riskcontrol, Injecta Prod. Odontológicos) were analysed: 10, immediately after the package was opened; 10, after a single use followed by disinfection with 70% alcohol for one minute; 30, after a single use without any posterior disinfection. The samples were transported to the laboratory and, under aseptic condition, rolled and compressed on a Tryptic Soy Agar surface with 5% of defibrillated sheep blood. After a 96-hour incubation, the reading was carried out with the help of a lens. According to the manufacture&#146;s information, the disposable tips were sterilized. In all of the tips used in patients, an uncountable amount of cfu (colony formation units) was found, revealing great contamination. In the disposable tips disinfected after being used, there was small bacterial growth, but that was incompatible with cross-contamination prevention. Therefore, we conclude that disposable air/water syringes tips must have a single use