Low level laser therapy does not modulate the outcomes of a highly bioactive glass–ceramic (Biosilicate®) on bone consolidation in rats

Abstract

The main purpose of the present work was to evaluate if low level laser therapy (LLLT) can improve the effects of novel fully-crystallized glass-ceramic (Biosilicate) on bone consolidation in tibial defects of rats. Forty male Wistar rats with tibial bone defects were used. Animals were divided into four groups: group bone defect control (CG); group bone defect filled with Biosilicate (BG); group bone defect filled with Biosilicate, irradiated with LLLT, at 60 J cm(-2) (BG 60) and group bone defect filled with Biosilicate, irradiated with LLLT, at 120 J cm(-2) (BG 120). A low-energy GaAlAs 830 nm, CW, 0.6 mm beam diameter, 100 W cm(-2), 60 and 120 J cm(-2) was used in this study. Laser irradiation was initiated immediately after the surgery procedure and it was performed every 48 h for 14 days. Fourteen days post-surgery, the three-point bending test revealed that the structural stiffness of the groups CG and BG was higher than the values of the groups BG60 and BG120. Morphometric analysis revealed no differences between the control group and the Biosilcate group. Interestingly, the groups treated with Biosilicate and laser (BG 60 and BG120) showed statistically significant lower values of newly formed bone in the area of the defect when compared to negative control (CG) and bone defect group filled with Biosilicate (CB). Our findings suggest that although Biosilicate exerts some osteogenic activity during bone repair, laser therapy is not able to modulate this process.