The effect of TEA CO2 laser irradiation to the Rat's mandibula

Abstract

It is generally known that infrared lasers have thermal side effect, which cause damage to the soft and hard tissues. The extent of thermal damage can be controlled by a choice of laser wavelength irradiance and exposure duration. Recently, it has been demon strated that soft and dental hard tissue can be removed by a long-pulse TEA CO2 laser irra diation with minimal thermal damage. However, there are few studies about the effects of the TEA CO2 laser on the bone tissue.The purpose of this study was to investigate the changes of the bone structure induced by TEA CO2 laser irradiation. The rat's mandibula in, in vitro (extripated) and in vivo condi tions were used. The bone surface was irradiated with TEA CO2 laser beam under the fol lowing conditions: wave length; 10.6μEm, output; 95m J/pulse, pulse repetition rate; 1Hz, irradiation time; 7.5μEs/shot, spot size; 0.8×1.5mm, energy density; 7.9J/cm2. Histological and scanning electron microscopical studies were performed. The same results were ob tained in the both cases (in-vitro and in-vivo). TEA CO2 laser beam produced defect with clean-cut margins. Histological examinations revealed presence of the thin basophilic line at the bottom and along the walls of defects. There was the superficial melting of the bone which is smeared by scanning electron microscopical findings. Although we found that the thermal damage at the bottom and along the sides of defects in bone was minimal, it was still observed. However, undesirable thermal effects like surface-cracking and carbonization were not observed. These findings suggested that it is possible to remove the bone tissue by TEA CO2 laser irradiation with minimal thermal changes. Therefore, further investigations have to be done to prove TEA CO2 laser for possible applications in dentistry.