RESUMO
Aim: The aim of present study was to evaluate if the cross-section and the number of use have influence in cyclic fatigue resistance of rotary files. Methods: K3 Endo (group K) and EndoSequence (group E) files, 25/.04, 25 mm, were subdivided into 3 subgroups (n=12) according to the number of uses, 1, 3 and 5 uses, totalizing 72 files. The files were submitted to dynamic assays device moved by an electric engine, using 300 rpm of speed that permitted the reproduction of pecking motion. The files run within a temperate steel ring's groove, simulating an instrumentation of a curved root canal with 40-degrees and 5-mm of curvature radius. The fracture of file was detected by sensor of device and the time and the number of cycles was acquired. The data were analyzed statistically by two-way ANOVA (p<0.05). Results: There were no statistical significant differences in regard to the number of uses (p>0.05). K3 Endo files showed greater resistance to cyclic fatigue than EndoSequence instruments (p<0.01). Conclusion: It may be concluded that the cross-section of instruments presented significant influence in cyclic fatigue resistance and the number of uses up to 5 times had no influence in cyclic fatigue resistance in both NiTi rotation systems evaluated
Assuntos
Titânio , Instrumentos Odontológicos , Fadiga , NíquelRESUMO
A importância crescente da estética na Odontologia para os pacientes e consumidores levou a constante elevação no número de produtos e procedimentos para facilitar a confecção do clareamento dental. Concomitantemente, houve aumento repentino no número de pesquisas e publicações, in vitro e in vivo, a respeito das suas possíveis reações adversas. Através de revisão de literatura, este trabalho tem por objetivo verificar as possíveis alterações morfológicas do esmalte e dentina submetidos ao clareamento com diversos agentes clareadores, fazendo análise crítica dos resultados das pesquisas atuais com relação ao estudo da microdureza e rugosidade superficial
The increasing importance of aesthetic in the Dentistry for the patients and the consumers brought a constant rise in the number of products and procedures to facilitate the confection of the dental bleaching. Concomitantly, thone was a sudden increase in the number of research and publications, in vitro and in vivo, about its possible adverse reactions. Through literature revision this study aims to verify the possible morphologic alterations of the submitted enamel and dentine with different bleaching agents making critical analysis of the results of the current research with relation to the study of the microhardness and superficial roughness
