HISTOLOGICAL-CHANGES INDUCED BY CO2-LASER MICROPROBE SPECIALLY DESIGNED FOR ROOT-CANAL STERILIZATION - IN-VIVO STUDY

Objective: Until now, no suitable delivery fiber has existed for CO2 l aser endodontic radiation in the apical region, where it is most diffi cult to eliminate the pulp tissue using conventional methods. To overc ome this problem, we have designed a microprobe that reaches closer to the apex, distributing the energy density to a smaller area of the ro ot canal and thus favorably increasing the thermal effects. Methods: A CO2 laser microprobe coupled onto a special hand piece was attached t o the delivery fiber of a Sharplan 15-F CO2 laser. The study was condu cted on 30 vital maxillary or mandibulary, central, lateral, or premol ar teeth destined for extraction due to periodontal problems. Twenty w ere experimentally treated with pulsed CO2 laser delivered by this new ly developed fiber after conventional root canal preparation. Temperat ure measured at three points on the root surface during laser treatmen t did not exceed 38 degrees C, Ten teeth represented the control group , in which only root canal preparation was performed in the convention al method, Results: Histological examination of the laser-treated teet h showed coagulation necrosis and vacuolization of the remaining pulp tissue in the root canal periphery. Primary and secondary dentin appea red normal in all cases treated with 15-F CO2 laser. Gram stain and ba cteriologic examination revealed complete sterilization, These results demonstrate the unique capabilities of this special microprobe in ste rilization of the root canal, with no thermal damage to the surroundin g tissue. Conclusions: The combination of classical root canal prepara tion with CO2 laser irradiation using this special microprobe before c losing the canal can drastically change the quality of root canal fill ings.