Influence of laser therapy on the dynamic formation of extracellular matrix in standard second degree burns treated with bacterial cellulose membrane.

The present study aims to assess the influence of Aluminum-Gallium-Indium-Phosphide laser (AlGaInP laser, λ = 660 nm), whether or not in association with the application of a membrane of bacterial cellulose (Nexfill™), during recovery from induced second-degree burns at the dorsum of Wistar rats. (Rattus norvegicus, Wistar). Forty-eight animals have been distributed into four groups: Control (burns remained untreated), Group I (laser-treated), Group II (treated with Nexfill), and Group III (laser + Nexfill™). In addition to a morphological analysis, immunohistochemical analysis has been performed for type I collagen, type III collagen, fibronectin, and laminin. The Fisher's Test was used to assess differences among groups (p < 0,05). A larger amount of collagen type III was observed in Control, Group II and Group III when compared with Group I (p < 0,05). Group I and Group III have shown a greater collagen deposition when compared with Group II (p < 0,05), but the amount of collagen was similar in Group I, Group III, and Control. Group III has shown larger fibronectin amounts in comparison with Group II (p < 0,05). As regards laminin, Group I has shown a predominant discontinuity pattern on the basal lamina in comparison with Control, Group II, and Group III (p < 0,05). It is concluded that in this current study the laser when used alone (Group I) hasn't influenced collagen deposition neither has it acted on fiber pattern (fibril and/or reticular). Moreover, laser application hasn't accelerated the repair of wounds caused by inflicted second-degree burns.

Laser and LED phototherapy on midpalatal suture after rapid maxilla expansion: Raman and histological analysis.

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 cm2, t = 257 s, SAEF of 18 J/cm2) or a LED (λ850 ± 10 nm, 150 ± 10 mW, spot of 0.5 cm2, t = 120 s, SAEF of 18 J/cm2) 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.