Resumo

SIQUEIRA, Thais Azzi Gonçalves et al. Influence of irrigant viscosity on torsional fracture resistance of rotary nickel-titanium instruments. RGO, Rev. gaúch. odontol. (Online) [online]. 2012, vol.60, n.3, pp. 309-314. ISSN 1981-8637.

Objective The main goal of the study was to evaluate the influence of the torsion caused by chemical substances with different viscosity levels on the fracture strength of nickel-titanium rotary dental instruments. Methods Tapered Instruments K3 #25 and 0.04 were used to prepare simulated canals with: Endo PTC, modified Endo PTC and distilled water. After 12 consecutive preparations using each instrument, they were submitted to the fracture test by torsion, which determined the resistance, in degrees, of each instrument in each experimental situation. Data were collected, analyzed and submitted to statistical analysis using the Kruskal-Wallis test. Results The statistical data analysis showed that there were no statistically significant differences as regards resistance to torsion of rotary instruments, with changes in level of viscosity of the substance that helps instrumentation. Conclusion Viscosity level of the chemical substance used during root canal preparation does not interfere in resistance to torsion of rotary instruments up to 12 consecutive times of use.

Palavras-chave : Dental pulp cavity.; Endodontics.; Root canal irrigants..