Root positioning and leakage to dye in extracted teeth using reduced pressure

A study was conducted in vitro to assess the root apex position on leakage to dye under reduced pressure (560 mm Hg). A total of 132 extracted single-rooted teeth were randomly allocated to four groups. The teeth were prepared using a step-back technique and sealed with the cold lateral condensation technique, using gutta-percha without sealer. No significant differences (P < 0.813) were found between horizontally positioned experimental groups under reduced pressure and those in passive immersion. In the group in which the apices were in an upright position, the mean leakage was significantly different (P < 0.024) from the mean dye penetration in the group of teeth positioned horizontally under reduced pressure. Those teeth with apices upright allowed the most linear leakage (0.51 mm), whereas the groups in which the roots were horizontally positioned (with and without reduced pressure) had the least dye penetration (0.21 mm and 0.19 mm, respectively). These results show that tooth positioning has a significant effect on linear dye penetration under reduced pressure and emphasize the need to standardize factors that may influence penetration when assessing leakage study methodology.