Bone repair following bone grafting hydroxyapatite guided bone regeneration and infra-red laser photobiomodulation: a histological study in a rodent model

Abstract

The aim of the investigation was to assess histologically the effect of laser photobiomodulation (LPBM) on a repair of defects surgically created in the femurs of rats. Forty-five Wistar rats were divided into four groups: group I (control); group II (LPBM); group III (hydroxyapatite guided bone regeneration; HA GBR); group IV (HA GBR LPBM). The animals in the irradiated groups were subjected to the first irradiation immediately after surgery, and it was repeated every day for 2 weeks. The animals were killed 15 days, 21 days and 30 days after surgery. When the groups irradiated with implant and membrane were compared, it was observed that the repair of the defects submitted to LPBM was also processed faster, starting from the 15th day. At the 30th day, the level of repair of the defects was similar in the irradiated groups and those not irradiated. New bone formation was seen inside the cavity, probably by the osteoconduction of the implant, and, in the irradiated groups, this new bone formation was incremental. The present preliminary data seem to suggest that LPMB therapy might have a positive effect upon early wound healing of bone defects treated with a combination of HA and GBR.

Repair of Surgical Bone Defects Grafted with Hydroxylapatite + β-TCP and Irradiated with λ=850 nm LED Light

“…This has been described in previous studies in which the use of LED was associated with increased proliferation of fibroblasts, chondroblasts and osteoblasts and hence increased deposition of collagen, an important precursor of the mineral matrix deposition (7,8,17). Thus, the increase in bone formation is probably closely linked with both the increased numbers of osteoblasts and their secretory activity.…”

“…These features were observed in many studies in which this group used similar parameters to the ones carried out with Laser Phototherapy (LPT) or LED-PT (2)(3)(4)(5)(6)(7)(8). It seems that the beneficial effects of LED-PT are similar to those of the laser.…”

“…This association may modulate the repair of bone defects in a manner similar to what is observed following the use of autologous bone graft, preventing its complications and limitations (2,4,5,8,11,12). However, the use of autologous grafts remains the gold standard for the treatment of bone defects (2,3).…”

“…Total energy delivered was 20 J/cm 2 per session and 140 J/cm 2 per treatment. Energy densities used were based upon previous studies carried out by the authors (1)(2)(3)(4)(5)(6)(7)(8)11,12). LED output power was confirmed by using a calibrated power meter (Thorlabs PM30-121; Thorlabs GmbH, Munich, Germany).…”

“…It is possible that the mechanism involved is similar to the light absorption by the cytochrome-C-oxidase present in the mitochondrial membrane (9,10). Despite the increase of successful reports of applications of different phototherapies in many areas, their use in bone repair associated with bone grafting with biomaterials needs to be further studied (4)(5)(6)(7)(8).…”