In vitro evaluation of external root temperature changes during Er:YAG laser application with five different fiber optic tip withdrawal techniques

Abstract

This study evaluated in vitro the external temperature increase at the three root thirds using five different fiber optic tip withdrawal techniques in 50 human canines. Er:YAG laser was applied with a 50/28 fiber optic tip with 250 mJ input, 112 mJ output, 10 Hz, 1 mm from the apical foramen: group 1: each third was irradiated starting at the apex for 1 s on each wall, with the irradiation turned off between thirds; group 2: apical third irradiated without movement for 2 s and tip withdrawn with continuous radiation up to the cervical third; group 3: tip activated at the apex and removed to the canal entrance in a straight line; group 4: tip activated at the apex and removed to the canal entrance with circular movements touching all walls; group 5: tip activated at the apex and removed to the canal entrance with clockwise circular movements for 6 s and then reinserting and removing with counterclockwise circular movements for another 6 s, touching all walls. Group 1 had significantly lower external temperature ( p<0.01). The middle third had the greatest temperature increase ( p<0.01). We conclude that the withdrawal techniques caused an increase in external root temperature that would not damage adjacent tissues.