Morphological changes of rat mandibular bone with ArF excimer laser in vivo

Objective: The purpose of this study was to investigate the morphological c hanges of bone tissue by ArF excimer laser irradiation in vivo, Summary Bac kground Data: Recently, it has been demonstrated that soft and hard tissues can be removed by excimer laser irradiation with little thermal damage, Me thods: ArF excimer laser was irradiated on the surface of the rat mandibula r bone using the following parameters: wavelength: 193 nn; output: 0.12 W; pulse repetition rate: 10 Hz; spot size: 1.0 x 4.0 mm; irradiation time: 90 and 120 seconds. The ablation depth was measured at 90 and 120 seconds. Fu rthermore, the irradiated surface was examined histologically using scannin g electron microscopy (SEM), Results: The relationship between ablation dep th and irradiation time was almost linear. Macroscopically, the ArF excimer laser beam produced a defect with clean-cut margins without carbonization in the mandibular bone, Histologically, there was minimal evidence of therm al damage to the surrounding tissue, The bottom of the defect revealed a sa wtooth appearance. In SEM observation, mosaic structures corresponded to th e sawtooth structures observed with light microscopy, Conclusions: These fi ndings suggest that it is possible to remove bone tissue using ArF excimer laser irradiation without thermal damage. The effectiveness of this laser c an be attributed to the photoablation of the bone tissue.