Objective: This in vitro experiment determined if there is an increase in the change in temperature (delta T) at the root surface (using multiple fiber optic guides 140µ, 200µ, 245µ, 300µ, 355µ and 410µ ) as a root canal is enlarged when using a HO:YAG laser. Methods: 90 recently extracted single rooted human teeth were assigned; Group 1, power setting of 0.5W ; Group 2, 0.75 W and Group 3, 1.00 W. T-type thermocouplers (Omega) were placed approximately 2 mm from the coronal and apical sites. The specimens in each of the three groups were subjected to lasing using fiber optic sizes of 140µ, 200µ, 245µ, 300µ, 355µ and finally 410µ. Statistical analysis was performed (RMANOVA, Student-Newman-Keuls (SNK) multiple comparisons test, and a Bonferroni correction was used to check for significance) and the dependent variables were: a) change in temperature (delta T) at the coronal and apical site, b) depth of tooth during lasing, c) depth of tooth using conventional files and d) tooth measurements. Results: RMANOVA for coronal temperature showed no significant difference between fibers and power settings and for apical temperature there was a significant difference between fibers and power settings. For the depth of tooth during lasing, a significant difference between fibers was observed. Pairwise contrasts revealed that fibers 140µ and 200µ were not different from one another and that fiber after 245µ were different from one another. In general, it was observed that the depth decreased as fiber size increased. Conclusions: All temperature differences observed apically and coronally were between 0° to 11°C. After lasing with the 410µ fiber, the root canals were sufficiently widened to at least a 45 K file. The results illustrate that lasing a root canal with a HO:YAG laser could be an efficient alternative to mechanical enlarging.

Back to the Dental Materials: VIII - Others-Non-metallic Program
Back to the 81st General Session of the International Association for Dental Research (June 25-28, 2003)

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