Safety Irradiation Parameters of Nd:YAP Laser Beam for Endodontic Treatments: An In Vitro Study

الملخص EN

Objective.

Nd:YAP laser has several potentialities of clinical applications in endodontics.

The aim of our study is to determine the safety range of irradiation parameters during endodontic application of Nd:YAP laser that can be used without damaging and overheating the periodontal tissue.

Material and Methods.

Twenty-seven caries-free single-rooted extracted human teeth were used.

Crowns were sectioned to obtain 11 mm root canal length.

Temperature increases at root surfaces were measured by a thermocouple during Nd:YAP laser irradiation of root canals at different energy densities.

Canal irradiation was accomplished with a circular and retrograde movement from the apex until the cervical part of the canal during 10 seconds with an axial speed of 1 mm/s.

Each irradiation was done in a canal irrigated continuously with 2.25% NaOCl solution.

Results.

Periodontal temperature increase depends on the value of energy density.

Means and standard deviations of temperature increases at root surfaces were below 10°C (safe threshold level) when the average energy densities delivered per second were equal to or below 4981 J/cm2 and 9554 J/cm2, respectively, for irradiations using a fiber diameter of 320 μm and 200 μm.

Conclusions.

Within the limitations of this study and under specific irradiation conditions, Nd:YAP laser beam may be considered harmless for periodontal tissues during endodontic applications.