EFFECT OF LOW INCIDENT LEVELS OF INFRARED LASER ENERGY ON THE HEALING OF EXPERIMENTAL BONE FRACTURES

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Adult male BALB/C mice were used to investigate the influence of low level diode laser therapy (830 nm 30 mW C/W and 904 nm, pulsed, peak power, 30 W) on tibial fracture healing. Quantifiable and reproducible bone fractures were produced following the method of Borque et al. Evaluation of bone radiographs was performed using a laser densitometer “UltroScan XL ”. It was demonstrated that after three weeks of a daily regimen of irradiation by laser beam at a power of 4.0 J/cm² the irradiated calluses presented significantly higher optical density on radiograms than the control (non-irradiated) calluses. The effect of pulsed 904 nm irradiation was significantly higher than 830 nm C/W laser irradiation. It was concluded that near infrared LLLT using diode lasers accelerates bone fracture healing. The authors suggest that the photoacoustic generation of an ultrasonic wave by the pulsed laser in the irradiated bone may play an additional role in the mechanism of callus formation.