Evaluation of the bone repair in defects grafted with hydroxyapatite and collagen membrane combined with laser therapy in rats

Abstract

Bone regeneration is the result of cellular events such as osteogenesis and neovascularization. However, implantation of autogenous grafts may be necessary in cases of bone mass loss due to high impact trauma. The disadvantages of the latter approach include morbidity of the donor area. Biomaterials represent an alternative for bone restoration. The most widely used compounds are collagen or hydroxyapatite membranes because of their biocompatibility and osteoconductivity. Laser therapy has been applied in combination with these implants to accelerate bone regeneration. The objective of this study was to evaluate the effects of low-level laser therapy (LLLT) on the healing of rat left tibial bone defects filled with hydroxyapatite or collagen membrane. Twenty rats were used. Surgical bone defects were created in the proximal third of the left tibia, and the animals were divided into four groups according to treatment: animals receiving hydroxyapatite implants (group H), animals receiving collagen implants (group C), animals treated with hydroxyapatite plus LLLT (group HL), and animals treated with collagen membrane plus LLLT (group CL). The animals were sacrificed 8 weeks after surgery, and the bone samples were obtained for analysis. Histomorphometrical methods were used for new bone quantification. Data were analyzed by analysis of variance (p < 0.05). Histological analysis showed the formation of new bone in the implant area with cortical aspect in groups. Bone neoformation was also demonstrated on radiographs as radiopacity of the hydroxyapatite granules and of the contour of the defects implanted with the collagen membrane. However, no significant difference for new bone formation was observed between the groups studied. The biomaterials used were presented good osteoconduction; however, the laser therapy protocol used was not adequate to accelerate the osteogenic process in the bone defect regeneration in the advanced bone healing process.

Use of a New Fibrin Sealant and Laser Irradiation in the Repair of Skull Defects in Rats

“…The effect of low-power laser irradiation in bone new formation depends on the intensity, frequency, type and time of application (3). Cunha et al (25) demonstrated that laser with energy density of 5.0 J/cm 2 was not adequate to accelerate the osteogenic process in bone defect regeneration and this was also observed in the present research. On the other hand, an energy density of 7 J/cm 2 showed a significant effect on new bone formation.…”

Bone substitutes and photobiomodulation in bone regeneration: A systematic review in animal experimental studies

“…Additionally, some parameters were calculated from existing data in the articles. It is possible to observe that all studies used infrared laser: six studies used 780 nm, 38,42‐45,48 four used 808 nm, 17,40,49,50 four used 830 nm 22,41,46,47 and 1used 904 nm 39 . Asanami, et al 37 did not inform this parameter on their study.…”

“…Among the articles analyzed, only two studies used rabbits as experimental model 37,38 and the others used rats to evaluate the effects of ceramic biomaterial and PBM in bone repair. Furthermore, nine studies performed the bone defect in the tibia of rats, 17,22,39‐45 three studies in the femur, 38,46,47 two studies in the calvaria 48,49 and two studies in the jaw 37,50 . Moreover, it was observed bone defects of distinct sizes of diameter, varying from 0.5 mm 50 to 5 mm 48,49 .…”

“…Thus, Table 3 demonstrates the kind of ceramic biomaterial (non‐ceramic materials evaluated by some articles were not shown in this table) and the energy per point used for each study. During the analysis of the articles, it was observed that 10 studies used HA (associated or not with other biomaterials) to fill the bone defects 37‐39,42‐47,50 . Moreover, five of them used a commercial biomaterial composed of HA and beta‐tricalcium phosphate 42‐45,50 .…”

“…Furthermore, studies demonstrated a power output window of 0.006 W 37 to 20 W, 39 with a mean of 1.46 W. In addition, different values of energy density were presented (with a mean of 78.51 J/cm 2 ). The energy per point remained within a window of 0.024 J 47 to 6 J 48 and a mean of 2.07 J.…”