Análise do transporte apical e da capacidade de centralização de instrumentos mecanizados de níquel-titânio em molares inferiores: protaper gold e prodesing logic

Abstract

This research aimed to evaluate the morphological changes resulting from the instrumentation of 20 mesial roots of severely curved lower human molars, and to compare the ProTaper Gold (PTG) and ProDesign Logic (PDL) systems through the analysis of apical canal transportation and centering ability beyond the time required for root canal preparation. The sample consisted of twenty anatomically paired lower molar mesial roots based on similar morphological dimensions using micro-CT evaluation (resolution = 19 µm) assigned to two experimental groups (n = 10) according to the system used for the preparation of root canal: Group 1 - PTG and Group 2 - PDL. The specimens were then digitized again and the corresponding mesial canal images, pre and post-instrumentation, were examined at three cross-sectional levels (3, 5 and 7 mm from the apical root end) to analyze apical canal transportation and centering ability. The ANOVA statistical test was applied, presenting normal distribution in relation to the apical canal transportation, not observing statistical difference between the groups (p> 0.05). For analysis of the centering ability, non-normal distribution was observed, and the Mann-Whitney test was applied, where a statistical difference was observed between the groups at the 5mm level (p = 0.0410) where PTG presented lower centering ability when compared to the PDL group. There was no correlation between the variables in question. Regarding the effective instrumentation time, the analysis showed that there was a statistically significant difference between the groups (p <0.0001), and a t-test was performed on related samples confirming the statistical difference (72.200; t = 9.3203; p < 0.001), being PDL faster to reach CT than the PTG group. All statistical procedures were performed with a significance level of 5%. Therefore, PTG and PDL had similar results in relation to the absence of apical canal transportation, PDL presented greater centering ability when referring to the 5mm level and was faster than PTG because a shorter instrumentation time was required. In addition, all systems were safe for clinical use once following manufacturers' recommendations.