Microinfiltração em restaurações de amálgama e seus métodos de avaliação / Microleakage in amalgam restorations and methods of evaluation

A ocorrência de microinfiltração em restaurações de amálgama tem sido considerada a principal causa para o desenvolvimento de lesões cariosas adjacentes às restaurações. Porém, percebe-se que não há padronização metodológica capaz de proporcionar uma interpretação segura e comparativa entre os estudos. O presente trabalho revisa a bibliografia e discute as metodologias utilizadas nos trabalhos de microinfiltração, questionando suas reais implicações.

Effects of a 10% carbamide peroxide bleaching agent on roughness and microhardness of packable composite resins.

PURPOSE: Bleaching agents containing 10% carbamide peroxide may be applied to the surface of preexisting packable resin-based composite restorations. The aim of this in vitro study was to evaluate the effect of a 10% carbamide peroxide bleaching agent (Review, SS White, Rio de Janeiro, Brazil) on surface roughness and microhardness of three packable resin-based composites (Fill Magic condensable, Vigodent, Rio de Janeiro, Brazil; Alert, Jeneric Pentron, Wallingford, CT, USA; Definite, Degussa, Hanau, Germany). MATERIALS AND METHODS: For the control (no bleaching) and experimental (bleaching treatment) groups, 12 specimens of each material were prepared in cylindrical acrylic molds. The experimental specimens were exposed to the bleaching agent for 6 hours a day for 3 weeks. During the remaining time (18 h), they were stored in artificial saliva. The control specimens remained immersed in artificial saliva throughout the experiment. Surface roughness and microhardness measurements were performed on the top surface of each specimen. RESULTS: Analysis of variance and the Tukey test showed no significant differences in roughness among the packable composites evaluated (p = .18), but those submitted to the treatment with a 10% carbamide peroxide bleaching agent displayed significantly higher mean surface roughness than did the corresponding control group for each material. For the microhardness tests, there were significant differences among materials (p < .0001). Alert showed the highest microhardness values followed by Definite and Fill Magic condensable. CONCLUSIONS: Ten percent carbamide peroxide bleaching agents may change the surface roughness of packable composites, but they do not alter their microhardness. CLINICAL SIGNIFICANCE: Under the conditions of this study, a 3-week bleaching regimen with 10% carbamide peroxide agents affected the roughness of packable composites. Nevertheless, the surface microhardness was not affected, although there were differences among the materials evaluated inherent to their composition.

Microleakage study of three adhesive systems

O objetivo deste estudo foi avaliar a eficácia de 3 sistemas adesivos hidrófilos na redução da microinfiltração de restaurações classe II. Foram selecionados 60 dentes molares humanos. Foi realizado em cada dente dois preparos classe II do tipo "slot vertical" nas superfícies mesial e distal, com margem cervical em dentina. As 120 cavidades foram sorteadas aleatoriamente em 3 grupos (n = 40), de acordo com o sistema adesivo testado G1: OptiBondo SOLO® (Kerr); G2: Amalgambond Plus® (Parkell); G3: Etch & Prime 3.0® (Degussa). As cavidades foram restauradas com resina composta Z 100 (3M/ESPE). As amostras foram termocicladas 2000 vezes (5 ± 1ºC e 55 ± 1ºC), durante 1 min em cada banho. Após a termociclagem, os dentes foram imersos em uma solução de azul de metileno a 2%, pH 7,0, durante 4 h, seccionados e observados em microscópio ótico MEIJI 2000 (35X). A avaliação foi realizada utilizando-se escores (0-4) e os resultados expressos através da soma das ordens. G1: 1994.00; G2: 2294.00; G3: 2972.00. Os 3 grupos foram significativamente diferentes. Os resultados indicaram que o sistema adesivo auto-condiconante Etch & Prime 3.0 foi menos efetivo no controle da microinfiltração marginal. Já o sistema adesivo OptiBond SOLO foi o mais efetivo no controle da microinfiltração quando comparado com o Amalgambond Plus e o Etch & Prime 3.0.

Microleakage study of three adhesive systems.

The purpose of this in vitro study was to evaluate the efficacy of three hydrophilic dentin adhesive systems to reduce class II restoration microleakage. A total of 60 human molar teeth were used in which two box cavities were made on the distal and mesial surfaces, with a cervical margin in dentin. These cavities were randomly divided into 3 groups (n = 40 each), according to adhesive system tested: G1: OptiBond SOLO; G2: Amalgambond Plus; G3: Etch & Prime 3.0. The cavities were restored with the composite resin Z-100. The groups were thermocycled 2000 times (5 +/- 1 degrees C and 55 +/- 1 degrees C) with a dwell time of 1 min. The teeth were then immersed in 2% methylene blue, pH 7.0, for 4 h, sectioned and observed with a stereomicroscope MEIJI 2000 (35X). The evaluation was made using scores (0-4) and the results were expressed through the sum of the ranks. G1 = 1994.00; G2 = 2294.00; G3 = 2972.00. The three groups were significantly different. The self-etching adhesive system Etch & Prime 3.0 was less effective in preventing microleakage. The OptiBond SOLO adhesive was the most effective in reducing microleakage in dentin margins when compared with Amalgambond Plus and Etch & Prime 3.0.

Avaliação da intensidade luminosa produzida por unidades fotoativadoras e grau de satisfação dos profissionais em empregá-las / Evaluation of light intensity of curing units and the satisfaction of the professionals with their photocuring units

O objetivo deste trabalho foi avaliar a intensidade luminosa emitida por unidades fotoativadoras das cidades de Cuiabá e Várzea Grande, MT, assim como o grau de satisfação dos profissionais com relação aos seus aparelhos fotoativadores. Foram avaliadas 403 unidades fotoativadoras, que apresentaram intensidade luminosa entre 0mW/cm² e 1000mW/cm² (0-233mW/cm² - 28,53%; 234-400mW/cm² - 37,71%; e 401-1000mW/cm² - 32,75%). A grande maioria dos profissionais participantes da pesquisa mostrou-se satisfeita com o desempenho de seus aparelhos

Microleakage of adhesively bonded cervical amalgam restorations.

PURPOSE: To evaluate dye penetration in adhesively bonded cervical amalgam restorations. MATERIALS AND METHODS: The specimens were randomly divided into four groups and the adhesives Prime & Bond 2.1, Prime & Bond 2.1 Dual Cure, Scotchbond Multi Purpose Plus and Amalgambond Plus were tested. After being restored and polished, the teeth were thermocycled 1,000 times at temperatures varying between 5 degrees C +/- 2 degrees C and 55 degrees C +/- 2 degrees C. Statistical analysis was carried out using the Kruskal-Wallis test and multiple comparisons. RESULTS: Scotchbond Multi-Purpose Plus demonstrated lower levels of microleakage in enamel and dentin. The dual adhesives were more effective than the "one bottle" adhesive.

Restauraçöes de amálgama adesivo: uma proposta eficaz na reconstruçäo de dentes extensamente destruídos / Adhesive amalgam restorations: an efficient proposal for the reconstruction of destroyed teeth

Neste trabalho foram discutidos aspectos importantes relacionados à técnica do amálgama adesivo, bem como foi apresentado um caso clínico em que esta técnica foi empregada com sucesso