Effects of continuous and pulsed infrared laser application on bone repair using different energy doses. Study in rats

Abstract

The Laser Therapy effects on the cellular proliferation are extensively searched and widely known. However, there are controversies on the best out put power used in the applications, the ideal fluency and irradiance, better emission mode and the adequate number of sessions in order to obtain the best results. The aim of this paper was to search for the best application fluency and emission mode, using an infrared laser in the repair of bone defects in the rat tibia. Thus, the histological quality of the neo-formed bone was evaluated by analysis using common optic microscopy and polarized light. Application Parameters: 100 mW, 830 nm, spot diameter = 0,06 nm, CW and 10 Hz, 3 sessions with 72 h of interval, energies and respective fluencies: 2 J =70 J/cm 2 4 J =140 J/cm2, 6 J =210 J/cm2, 8 J =160 J/cm2, 10 J =200 J/cm2. Conclusions: Laser Therapy has increased and accelerated the time bone repairing process (in the initial period of 10 days). This laser effect showed to be dose-dependent with the presence of an effective therapeutic window presenting biostimulation of the bone tissue between 4J and 8 J of total energy for both emission mode. The use of the laser with 10 J of energy generated, characterized by the bioinhibition of the tissues (in the initial period of 10 days). This inhibition took place at the exact irradiation spot).