TEMPERATURE CHANGES ON THE EXTERNAL ROOT CANAL SURFACE DURING ND:YAG AND KTP:YAG LASER IRRADIATION

The aim of this study was to assess temprature rises which occured at five different points at external root canals after the application intracanal two different laser irradiation. sixty mandibular premolar human teeth with a single canal were used in this study. extraction teeth were cut from crown-root junction to the dentin by sectioning the tooth perpendicular to its long axis using a low-speed saw (isomet, buehler ltd, lake bluff, il, usa). the working length was computed and then root canals were prepared with protaper rotary files by using crown down technique. teeth were divided into six groups. two different laser and three different powers of irradition (watt) were used. the holes were opened on apparatus to fix the teeth. two of these holes are on the coronal 1/3, two of are on the apical 1/3 and one of them is on apex. l type termocouple cables (elimko co., türkiye) were placed in these holes which were opened for measurement. the temperature rises were recorded on external root canal with universal data loggers/scanners. data was assessed with two way anova analysis, tukey and pairedsamples t test. among all groups, only the differences between ktp and nd:yag lasers were found statisticaly significant (p<0.05). at both of the lasers, the highest temperature rises observed on the apex, whereas the lowest ones were on the median 1/3 region. when nd-yag laser was applied higher than 1 watt in the root canals, it was observed dangerously high temperature rise occured on external root surface.