Effect of Low-Level Laser Therapy on Incorporation of Block Allografts

OBJECTIVE To assess the effect of low-level laser therapy (LLLT) on the incorporation of deep-frozen block allografts in a rabbit model. BACKGROUND DATA Studies have shown that LLLT has beneficial effects on tissue repair and new bone formation. METHODS Bone tissue was harvested from two rabbits, processed by deep-freezing and grafted into the calvaria of 12 animals, which were then randomly allocated into two groups: experimental (L) and control (C). Rabbits in group L were irradiated with an aluminum gallium arsenide diode laser (AlGaAs; wavelength 830 nm, 4 J/cm(2)), applied to four sites on the calvaria, for a total dose of 16 J/cm(2) per session. The total treatment dose after eight sessions was 128 J/cm(2). Animals were euthanized at 35 (n = 6) or 70 days (n = 6) postoperatively. RESULTS Deep-freeze-processed block allografts followed by LLLT showed incorporation at the graft-host interface, moderate bone remodeling, partial filling of osteocyte lacunae, less inflammatory infiltrate in the early postoperative period, and higher collagen deposition than the control group. CONCLUSION Optical microscopy and scanning electron microscopy showed that allograft bone processed by deep-freezing plus LLLT is suitable as an alternative for the treatment of bone defects. Use of the deep-freezing method for processing of bone grafts preserves the structural and osteoconductive characteristics of bone tissue.