Como as tecnicas restauradoras podem influenciar na qualidade das restaurações esteticas : avaliação da microdureza, selamento marginal e resistencia de união

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The development of new restorative adhesive techniques has continuously advanced resulting in huge changes in the adhesive Dentistry. Thus, in this study it was evaluated the influence of some factors involved during the photoactivation procedures on the marginal adaptation and microhardness of Class II resin composite restorations; it was also investigate the influence of the methodologies used to evaluate the bond strength of adhesive materials to the dental substrate. The aims of this study, composed of four scientific articles were: A) to evaluate the microleakage and microhardness of resin composite restorations using three polymerization techniques (conventional, plasma arc curing and soft-start) and two different resin composites (one microhybrid and one packable) (Article 1); B) to evaluate the influence of four photoactivation systems (halogen (QTH); light emitting diode (LED); argon ion laser (AL) and plasma arc curing (PAC)) on microleakage (Article 2), gap formation and microhardness (Article 3) of class II restorations ? at dentin and enamel margins, using a microhybrid Filtek Z250 and two packable resin composites (SureFil and Tetric Ceram HB); C) to evaluate the behavior of two adhesive systems: the self-etching primer Clearfil Liner Bond 2V and the total-etch Single Bond when submitted to two bond strength tests: shear bond strength and microtensile. The results showed that the polymerization techniques - conventional, plasma arc curing and soft-start ? did not affect the microleakage when a microhybrid resin composite was used. When a packable composite was used, restorations polymerized with Conventional technique presented similar microleakage to restoration polymerized with soft-start and lower than with plasma arc (Article 1). However, no significant differences were found in the microleakage scores among the photoactivation systems and among resin composites used, marginal adaptation was not significantly affected by location (enamel vs. cementum margins) (Article 2). Related to gap formation, there was no significant difference in gap formation among the curing systems and resin composites at enamel margins. However at the dentin margins, the photoactivation methods did not reveal significant differences, but the microhybrid resin composite presented the best results (Article 3). No statistically significant differences were noted between KHN values of Filtek Z250 and Surefil, but Tetric Ceram HB had the lowest KHN. Occlusal and middle KHN were significantly higher than gingival KHN for all materials (Articles 1 and 3). Article 4 demonstrated that specimens used in the microtensile bond strenght test might provide a more accurate detection of differences among the adhesive systems. These findings suggested that different photoactivation systems may have no effect on the microhardness and gap formation, but the resin composite formulation were found to be a significant determinant factor; and that the methodology chosen may interfere in the detection of data

ASSUNTO(S)

composite resins resinas compostas resistencia ao cisalhamento shear strength

ACESSO AO ARTIGO

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