An in vitro study of the effect of spreader penetration depth on apical microleakage.

The purpose of this study was to evaluate the effect of spreader penetration depth on apical microleakage using the lateral compaction method. A total of 96 extracted maxillary central incisors were instrumented using the step-back method, and randomly divided into the following four experimental groups: A) with tug-back and spreader penetration 1 mm short of the working length; B) without tug-back and spreader penetration 1 mm short of the working length; C) without tug-back and spreader penetration to the working length; D) with tug-back and spreader penetration to the working length. Microleakage evaluation was conducted using the dye penetration method, and ANOVA test was used for statistical analysis. The results showed that there was a significant difference in the amount of microleakage between the groups with spreader penetration to the working length and the groups with spreader penetration 1 mm short of the working length. There was no significant difference between the groups with and without tug-back.