Effect of Low-Level Laser on Bone Defects Treated with Bovine or Autogenous Bone Grafts: In Vivo Study in Rat Calvaria

Objective. The purpose of this study was to histologically evaluate the effect of low-level laser (LLL) on the healing of critical size defects (CSD) in rat calvaria, filled with autogenous or inorganic bovine bone grafts. Methods. Sixty rats were divided into 6 groups (n = 10): C (control-filled with blood clot), LLL (low-level laser-GaAlAs, lambda 780 nm, 100 mW, 210 J/cm(2), Phi 0.05 cm(2); 6 J/point), AB (autogenous bone), ABL (autogenous bone + low-level laser), OB (inorganic bovine bone), and OBL (inorganic bovine bone + LLL). Material and Methods. The animals were killed after 30 days. Histological and histometric analyses were performed by light microscopy. Results. The groups irradiated with laser, LLL (47.67% +/- 8.66%), ABL (39.15% +/- 16.72%), and OBL (48.57% +/- 28.22%), presented greater area of new bone formation than groups C (9.96% +/- 4.50%), AB (30.98% +/- 16.59%), and OB (11.36% +/- 7.89%), which were not irradiated. Moreover, they were significantly better than group C (Kruskal-Wallis test followed by Dunn test, P < 0.05). Conclusion. The laser accelerated the healing of bone defects and the resorption of particles of the graft material.