• Antonio Luiz B Pinheiro, Luiz Guilherme P Soares, Aparecida Maria C Marques, Jouber Mateus S Aciole, Renato Aparecido de Souza, and Landulfo Silveira.
• Center of Biophotonics, School of Dentistry, Federal University of Bahia - UFBA, Av. Araújo Pinho, 62, Canela, Salvador, BA 40110-150, Brazil; National Institute of Optics and Photonics, University of São Paulo - USP, Physics Institute of São Carlos, Av. Trabalhador São-Carlense, 400 - Pq. Arnold Schimidt, São Carlos, SP 13566-590, Brazil; Biomedical Engineering Institute, Universidade Camilo Castelo Branco - UNICASTELO, Parque Tecnológico de São José dos Campos, Estr. Dr. Altino Bondesan, 500, Eugênio de Melo, São José dos Campos, SP, Brazil. Electronic address: albp@ufba.br.
• J. Photochem. Photobiol. B, Biol. 2014 Sep 5; 138: 146-54.

AbstractThis work aimed to assess biochemical changes associated to mineralization and remodeling of bone defects filled with Hydroxyapatite+Beta-Beta-tricalcium phosphate irradiated or not with 2 light sources. Ratios of intensities, band position and bandwidth of selected Raman peaks of collagen and apatites were used. Sixty male Wistar rats were divided into 6 groups subdivided into 2 subgroups (15th and 30th days). A standard surgical defect was created on one femur of each animal. In 3 groups the defects were filled with blood clot (Clot, Clot+Laser and Clot+LED groups) and in the remaining 3 groups the defects were filled with biomaterial (Biomaterial, Biomaterial+Laser and Biomaterial+LED groups). When indicated, the defects were irradiated with either Laser (λ780 nm, 70 mW, Φ∼0.4 cm(2)) or LED (λ850±10 nm, 150 mW, Φ∼0.5 cm(2)), 20 J/cm(2) each session, at 48 h intervals/2 weeks (140 J/cm(2) treatment). Following sacrifice, bone fragments were analyzed by Raman spectroscopy. Statistical analysis (ANOVA General Linear Model, p<0.05) showed that both grafting and time were the variables that presented significance for the ratios of ∼1660/∼1670 cm(-1) (collagen maturation), ∼1077/∼854 cm(-1) (mineralization), ∼1077/∼1070 cm(-1) (carbonate substitution) and the position of the ∼960 cm(-1) (bone maturation). At 30th day, the ratios indicated an increased deposition of immature collagen for both Clot and Biomaterial groups. Biomaterial group showed increased collagen maturation. Only collagen deposition was significantly dependent upon irradiation independently of the light source, being the amount of collagen I increased in the Clot group at the end of the experimental time. On the other hand, collagen I deposition was reduced in biomaterial irradiated groups. Raman ratios of selected protein matrix and phosphate and carbonate HA indicated that the use of biphasic synthetic micro-granular HA+Beta-TCP graft improved the repair of bone defects, associated or not with Laser or LED light, because of the increasing deposition of HA.Copyright © 2014 Elsevier B.V. All rights reserved.

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