Our results suggest that the use of PL (10.2 J/cm(2)) improves the healing of third-degree burns on both diabetic and nondiabetic animals.

The aim of this study was to analyze the effect of laser or LED phototherapy on the acceleration of bone formation at the midpalatal suture after rapid maxilla expansion. Forty-five rats were divided into groups at 7 days (control, expansion, expansion and laser irradiation, and expansion and LED irradiation) and into 14 days (expansion, expansion and laser in the 1st week, expansion and LED in the 1st week, expansion and laser in the 1st and 2nd weeks, expansion and LED in the 1st and 2nd weeks). Laser/LED irradiation occurred every 48 h. Expansion was accomplished with a spatula and maintained with a triple helicoid of 0.020-in stainless steel orthodontic wire. A diode laser (λ780 nm, 70 mW, spot of 0.04 cm, t = 257 s, SAEF of 18 J/cm) or a LED (λ850 ± 10 nm, 150 ± 10 mW, spot of 0.5 cm, t = 120 s, SAEF of 18 J/cm) was applied in one point in the midpalatal suture immediately behind the upper incisors. Raman spectroscopy and histological analyses of the suture region were carried and data was submitted to statistical analyses (p ≤ 0.05). Raman spectrum analysis demonstrated that irradiation increases hydroxyapatite in the midpalatal suture after expansion. In the histological analysis of various inflammation, there was a higher production of collagen and osteoblastic activity and less osteoclastic activity. The results showed that LED irradiation associated to rapid maxillary expansion improves bone repair and could be an alternative to the use of laser in accelerating bone formation in the midpalatal suture.

This study aimed to assess bone repair in defects grafted or not with hydroxyapatite (HA) on healthy and iron-deficiency anemia (IDA) rats submitted or not to LED phototherapy (LED-PT) by Raman spectroscopy. The animals were divided in eight groups with five rats each: Clot; Clot + LED; IDA + Clot; IDA + LED; Graft; Graft + LED; IDA + Graft; and IDA + Graft + LED. When appropriated, irradiation with IR LED (λ850 ± 10 nm, 150 mW, CW, Φ = 0.5 cm(2), 16 J/cm(2), 15 days) was carried out. Raman shifts: ∼ 960 [symmetric PO4 stretching (phosphate apatite)], ∼ 1,070 [symmetric CO3 stretching (B-type carbonate apatite)], and ∼ 1,454 cm(-1) [CH2/CH3 bending in organics (protein)] were analyzed. The mean peak values for ∼ 960, ∼ 1,070, and ∼ 1,454 cm(-1) were nonsignificantly different on healthy or anemic rats. The group IDA + Graft + LED showed the lowest mean values for the peak ∼ 960 cm(-1) when compared with the irradiated IDA group or not (p ≤ 0.001; p ≤ 0.001). The association of LED-PT and HA-graft showed lowest mean peak at ∼ 1,454 cm(-1) for the IDA rats. The results of this study indicated higher HA peaks as well as a decrease in the level of organic components on healthy animals when graft and LED phototherapy are associated. In the other hand, IDA condition interfered in the graft incorporation to the bone as LED phototherapy only improved bone repair when graft was not used.

Laser and LED phototherapies accelerate tissue repair. Mast cells induce the proliferation of fibroblasts and the development of local fibrosis. Increased numbers of myofibroblasts and mast cells are frequently found together in a normal wound repair, suggesting that mediators produced by the mast cells could play a role in the regulation of myofibroblast differentiation and function. The aim of this study was to analyze the involvement of mast cells on the synthesis of collagen and their influence on myofibroblast differentiation in the late phase of tissue repair on wounds treated with LLLT (λ 660 nm, 10 J/cm(2), 40 mW, 252 s) or LED (λ 630 ± 10 nm, 10 J/cm(2), 115 mW, 87 s). A 1 × 1-cm surgical wound was created on the dorsum of 30 rats divided into three groups of ten animals each: control, laser, and LED. The animals of each group were irradiated and sacrificed 7 and 14 days after injury. The statistical analysis was performed using the Mann-Whitney and Spearman correlation tests. Laser light improved the collagen deposition rate along the time points (p = 0.22), but when compared to the control groups during the periods studied, the number of mast cells decreased significantly (p ≤ 0.05). With respect to myofibroblasts, the results showed a trend to their reduction. No statistical significances were observed for LED light according to the parameters used in this study. It is concluded that the mast cell and myofibroblast population might participate in the collagen formation of irradiated wounds particularly in relation to laser phototherapy.

Osteoporosis is a disease characterized by the reduction of bone mineral density. LED wavelengths seem to have similar photo-stimulating effects to laser light. The aim of this study was to assess the Raman shifts: ∼ 960 (phosphate hydroxyapatite), ∼ 1,070 (carbonate hydroxyapatite), and ∼ 1,454 cm (-1) (lipids and proteins) on bone defects of ovariectomized rats treated or not with LED phototherapy (LED-PT). Thirty female rats were divided into four groups (Basal, OVX, OVX+Clot, and OVX+Clot+LED), then subdivided into two subgroups (15 and 30 days after surgery). Osteoporosis induction by ovariectomy (OVX) was performed in all groups, except for the normal basal group. Following development of osteoporosis, one surgical bone defect (5 mm(2)) was created on the femur of each animal. Defects were irradiated with LED light (λ = 850 ± 10 nm, P = 150 mW, CW, Ф = 0.5 cm(2), 20.4 J/cm(2) per session, t = 128 s, 163.2 J/cm(2) per treatment) at 48 h interval during 2 weeks. Raman measurements were taken at the surface of the defects 30 days after surgery. Significant difference between groups Basal, OVX+Clot, and OVX+Clot+LED for the peaks at ∼ 960 (p ≤ 0.001; 15 and 30 days), ∼ 1,070 (p ≤ 0.001; 15 and 30 days), and ∼ 1,450 cm(-1) (p = 0.002; 15 days; p = 0.004; 30 days) were detected. In addition, statistical differences were obtained between groups OVX, OVX+Clot, and OVX+Clot+LED for these same peaks at all time points (p ≤ 0.001). At 15 and 30 days, there were statistical differences between groups OVX+Clot and OVX+Clot+LED for the peaks at ∼ 960 (p ≤ 0.001), ∼ 1,070 (p ≤ 0.001; p = 0.003), and ∼ 1,450 cm(-1) (p ≤ 0.001; p = 0.002). The results of this study are indicative that infrared LED-PT improved the deposition of HA on bone defects of ovariectomized rats.