Thermal increase in the oral mucosa and in the jawbone during Nd:YAG laser applications. Ex vivo study.
OBJECTIVE
Literature reports bactericidal and biostimulant effects for Nd:YAG laser procedures on bone and oral mucosa but the possible overheating can cause damage to anatomical structures. The aim of the study was to evaluate the is the evaluation of thermal increase in different levels of oral tissues: mucosa, periosteum and bone during defocused application of Nd:YAG laser at different parameters.


METHODS
Superficial thermal evaluation was performed in pig jaws with a thermal camera device; deep thermal evaluation was realized by 4 thermocouples placed at a subperiosteal level and at 1,2 and 4 mm depth in the jaw bone. Laser applications of 1 minute were performed 5 times (with a pause of 1 minute) on a surface of 4 cm² with a Nd:YAG laser (MSP mode, 320 micrometer fiber, defocused mode) with different parameters. Temperatures were recorded before and after laser applications and after each pause in order to evaluate also the thermal relaxation of tissues.


RESULTS
At submucosal level, mean thermal increase was between 1.1°C and 13.2°C, at 1 mm depth between 1.1°C and 8.5°C, at 2 mm depth between 1.1°C and 6.8°C, at 4 mm depth between 1.0°C and 5.3°C. Temperature decrease during the rest time period was variable between 0°C and 2.5°C.


CONCLUSIONS
Temperatures reached during clinical procedures with parameters reported in the literature in biostimulation protocols (1.25-2 Watts) for the five minutes of application are not dangerous for biological structures. The decrease in temperature during the rest time period is less considerable in the bone in comparison to oral mucosa.
Unit of Oral Medicine, Oral Pathology and Laser-Assisted Oral Surgery, Department of ENT-Dental Ophtalmological and Cervico-Facial Sciences, University of Parma, Italy.
Paolo
P
Vescovi
Elisabetta
E
Merigo
Carlo
C
Fornaini
Jean-Paul
JP
Rocca
Samir
S
Nammour
D000818:Animals; D001831:Body Temperature; D006358:Hot Temperature; D066298:In Vitro Techniques; D007568:Jaw / Q000528:radiation effects*; D053844:Lasers, Solid-State; D009061:Mouth Mucosa / Q000528:radiation effects*; D013552:Swine