Biomodulatory effects of LLLT on bone regeneration

Antonio L.B. Pinheiro1, Marilia G. Oliveira2, Pedro Paulo M. Martins3, Luciana Maria Pedreira Ramalho4, Marcos A. Matos de Oliveira5, Aurel’cio Novaes Jœnior and Renata Amadei Nicolau

1 School of Dentistry, Department of Diagnostic and Therapeutics, Universidade Federal da Bahia, Salvador, BA, 40110-150,Brazil; 2 School of Dentistry, Post-Graduate Program on Oral and Maxillofacial Surgery, Pontif’cia Universidade Cat—lica do Rio Grande do Sul, Porto Alegre, RS, Brazil; 3School of Dentistry, University of Pernambuco, Camaragibe, 50000-000,Brazil; 4School of Dentistry, Laser Center, Universidade Federal da Bahia, Salvador, BA, 40110-150,Brazil; 5Lecture, Institute of Research and Development (IP&D) Universidade Vale do Para’ba (UNIVAP) – S‹o JosŽ dos Campos,SP, 12244-000, Brazil.

Low Level Laser Therapy (LLLT) for wound healing is effective in modulating both local and systemic response. Usually the healing process of bone is slower than that of soft tissue. Effects of LLLT on bone are still controversial. This paper reports observations on the effect of LLLT on bone healing. The amount of newly formed bone after 830nm laser irradiation of surgical wounds created in the femur of rats was evaluated morphometricaly. Forty Wistar rats were divided into four groups: group A (12 sessions, 4.8J/cm2 per session, 28 days); group C (three sessions, 4.8J/cm2 per session, seven days). Groups B and D acted as non-irradiated controls. Forty-eight hours after the surgery, the defects of the laser groups were irradiated transcutaneously with a CW 40mW 830nm diode laser, (f~1mm) with a total dose of 4.8J/cm2. Irradiation was performed three times a week. Computerized morphometry showed a significant difference between the areas of mineralized bone in groups C and D (p=0.017). There was no significant difference between groups A and B (28 days) (p=0.383). In a second investigation, the effects of LLLT on bone healing after the insertion of implants were determined. Dental implants need four and six months for fixation on the maxillae and on the mandible before loading. Ten male and female dogs were divided into two groups of five animals that received the implant. Two animals of each group were controls. Animals were sacrificed 45 and 60 days after surgery. The animals were irradiated three times a week for two weeks in a contact mode with a CW 40mW 830nm diode laser, (f ~1mm) with a total dose per session of 4.8J/cm2 and a dose per point of 1.2J/cm2. Better bone healing after irradiation with the 830nm diode laser were shown from the SEM study, suggesting that, under experimental conditions of the investigation, LLLT at 830nm significantly improves bone healing at early stages. and may increase bone repair at early stages of healing.