Removal of fiber posts during endodontic retreatments using ultrasonic tips: A comparison between two different endodontic fiber posts

Aim: The purpose of this study was to evaluate temperature changes generated on radicular surface of extracted monoradicular teeth during ultrasonic removal of fiber posts. Methodology: Forty intact monoradicular teeth, with not less than 15 mm root canal length, with mature apex and without root fractures, were selected. After root canal instrumentation and obturation of teeth, dowel space preparation was obtained at 9 mm length. Samples were randomly divided into two groups according to the type of fiber post used: the first group received quartz fiber posts D.T. Light Post n. 0.5; the second group cemented silica fiber post TECHOLE S with central hole. Removal technique was performed with microblades ultrasonic tips, in particular Start-X #3. Operative protocol provided succession of dry use of ultrasonic inserts for a period of 25 s, air cooling for 25 s and water cooling for 25 s, until posts entire removal. Thermographic measurements were recorded taking photography and videos using Thermal Imaging Camera FLIR-One. Results: Results show that dry use leads to rapid increase in root surface temperature beyond critical limit, while both air cooling and water one decreases it to lower value for both of groups. The best results were obtained by water cooling. Conclusions: Air or water cooling seems to be essential during the use of ultrasonic tips to reduce the risk of periodontal tissue and bone damage due to an excessive temperature raise. It's necessary to increase the samples number to conduct statistical analyses.