[Microleakage in class V amalgam restorations lined with and without varnish and dentin bonding agents using different amalgams: An in vitro study]

Microleakage is an important problem for amalgam restorations and causes teeth discoloration, pulp irritation, sensitivity and caries. The aim of this study was to determine and compare the in vitro microleakage of 3 different dental amalgams with commercial names [Cinalux, Dentam, SS White] using a dentin bonding agent [Excite] and a cavity varnish [Compalite], in class V amalgam restorations. Class V preparation measuring 3x2x2 mm were cut on the facial surfaces of 78 freshly extracted human premolar teeth. The teeth were divided into 3 groups of 20 teeth and 2 groups of 9 teeth as positive and negative control. They were restored using the material of choice following manufacture's instructions, and thermocycled between 4+2 C° and 54 +/- 4 C° for 700 cycles in 105 seconds. The teeth were subsequently immersed in methylene blue dye and sectioned to allow assessment of microleakage with stereomicroscope. The obtained data were analyzed by Kruskal-wallis and Mann-whitney U tests. Non-parametric statistical analysis showed significant differences between 3 different amalgams when the cavities lined by Excite [P<0.05]. There was no significant differences between 3 different amalgams when the cavities lined by varnish. These results suggested dentin bonding agents reduced microleakage in comparison to varnish, and the type of amalgam is effective on microleakage

Ligas para amálgama contendo zinco: quando devemos usá-las? / Dental amalgam alloy containing zinc: when should we use them?

O presente estudo teve por objetivo avaliar, por revisäo da literatura, o efeito da inclusäo do zinco nas ligas de amálgama dentário. Para isso, foram analisadas a microestrutura, as propriedades físicas, a corrosäo, a deterioraçäo, fraturas marginais e a citoxicidade do amálgama

Efeito de sistemas adesivos na resistência à fratura de pré-molares superiores humanos restaurados com amálgama / Effect of bonded amalgam on the fracture resistance of human premolars

Comparou-se, in vitro, a resistência à fratura de pré-molares superiores humanos com preparos cavitários MOD extensos em cinco diferentes situaçöes: preparos näo restaurados, restaurados com amálgama ou restaurados pela técnica que associa o amálgama aos adesivos All Bond 2, Amalgambond Plus e Scotchbond Multi Uso Plus. As amostras restauradas permaneceram armazenadas em água destilada por 24 horas em uma estufa a 37ºC, para entäo serem submetidas ao carregamento axial de compressäo na máquina de ensaios universal Kratos. Os valores de resistência obtidos foram submetidos a Análise de Variância a um critério e ao teste estatístico Student-Newman-Keuls. Os resultados permitiram concluir que resistência à fratura de pré-molares superiores humanos com restauraçöes MOD de amálgama forradas com os sistemas adesivos Amalgambond Plus (79,5Kgf), Scotchbond Multi Uso Plus (85,4Kgf) e All Bond 2 (86,1Kgf) näo é estatisticamente superior àqueles restaurados com amálgama associado ao verniz cavitário (80,5Kgf) e que os dentes näo restaurados (61,8Kgf) apresentaram resistência significantemente inferior aos demais grupos restaurados

Effects of designs of Class 2 preparations on resistance of teeth to fracture.

This study was designed to evaluate the effect of isthmus width on the strength of the remaining tooth structure in maxillary first premolars restored with class 2 silver amalgam restorations. One hundred ten sound maxillary first premolars freshly extracted as a part of orthodontic treatment were collected. The teeth were then divided into 10 groups of 11 teeth each. Ideal class 2 mesio-occlusal, disto-occlusal and mesio-occlusodistal cavities with different isthmus widths i.e. one half the intercuspal distance, one third the intercuspal distance and one fourth the intercuspal distance and one fourth the intercuspal distance were prepared. Compressive forces were applied using a Universal Testing Machine and load to the point of fracture was determined. Intact teeth produced the best tooth fracture resistance i.e. 105.4 MPa, followed by preparations with isthmus width of one fourth, one third and one half intercuspal distance in the order.

Amalgama dental: ¿obturación funcional o simple relleno cavitario? / Dental amalgam: functional obturation or simple cavity filling?

Siendo la amalgama el material restaurador más utilizado en odontología, aún cien años después, sus resultados clínicos en general dejan mucho que desear, más por un manejo inadecuado del material que por el material mismo. Se presenta aquí una clasificación del material con la idea de conocer más sobre su desarrollo. Es indudable que con el desarrollo tecnológico, las preparaciones cavitarias para restauraciones con amalgama hayan sufrido grandes modificaciones si se comparan con las utilizadas a principios de siglo, existiendo una nueva propuesta de diseño cavitario. Al final se hacen algunas observaciones sobre tres grandes factores que inciden en el desarrollo de una buena restauración: fractura marginal, falta de armonía y función oclusal y excesos interproximales, con lo que se busca que el operador mejore la forma de trabajo con dicho material y se aumente el éxito para lograr con la amalgama dental