title: Low-level laser therapy stimulates bone metabolism and inhibits root resorption during tooth movement in a rodent model.
abstract: This study evaluated the biological effects of low-level laser therapy (LLLT) on bone remodeling, tooth displacement and root resorption, occurred during the orthodontic tooth movement. Upper first molars of a total of sixty-eight male rats were subjected to orthodontic tooth movement and euthanized on days 3, 6, 9, 14 and 21 days and divided as negative control, control and LLLT group. Tooth displacement and histomorphometric analysis were performed in all animals; scanning electron microscopy analysis was done on days 3, 6 and 9, as well as the immunohistochemistry analysis of RANKL/OPG and TRAP markers. Volumetric changes in alveolar bone were analyzed using MicroCT images on days 14 and 21. LLLT influenced bone resorption by increasing the number of TRAP-positive osteoclasts and the RANKL expression at the compression side. This resulted in less alveolar bone and hyalinization areas on days 6, 9 and 14. LLLT also induced less bone volume and density, facilitating significant acceleration of tooth movement and potential reduction in root resorption besides stimulating bone formation at the tension side by enhancing OPG expression, increasing trabecular thickness and bone volume on day 21. Taken together, our results indicate that LLLT can stimulate bone remodeling reducing root resorption in a rat model. LLLT improves tooth movement via bone formation and bone resorption in a rat model.
authors.affiliation: CLA - Center for Laser and Applications, Nuclear and Energy Research Institute, IPEN-CNEN/SP, Brazil.
authors.forename: Selly Sayuri
authors.initials: SS
authors.lastname: Suzuki
authors.affiliation: Department of Microbiology, São Leopoldo Mandic School and Dental Institute, Campinas, SP, Brazil.
authors.forename: Aguinaldo Silva
authors.initials: AS
authors.lastname: Garcez
authors.affiliation: Department of Orthodontics, São Leopoldo Mandic School and Dental Institute, Campinas, SP, Brazil.
authors.forename: Hideo
authors.initials: H
authors.lastname: Suzuki
authors.affiliation: Department of Basic Science and Embryology and Histology, Dental School of Araçatuba - UNESP, Brazil.
authors.forename: Edilson
authors.initials: E
authors.lastname: Ervolino
authors.affiliation: Section of Orthodontics, UCLA School of Dentistry, Los Angeles, CA, USA.
authors.forename: Won
authors.initials: W
authors.lastname: Moon
authors.affiliation: CLA - Center for Laser and Applications, Nuclear and Energy Research Institute, IPEN-CNEN/SP, Brazil.
authors.forename: Martha Simões
authors.initials: MS
authors.lastname: Ribeiro
mesh_terms: D000818:Animals; D016723:Bone Remodeling / Q000528:radiation effects*; D028022:Low-Level Light Therapy; D008297:Male; D008963:Molar; D010010:Osteoclasts / Q000528:radiation effects; D053245:RANK Ligand / Q000378:metabolism; D051381:Rats; D012391:Root Resorption / Q000517:prevention & control / Q000532:radiotherapy*; D014087:Tooth Movement Techniques
chemical_list: D053245:RANK Ligand
keywords: OPG; RANKL; TRAP; bone remodeling; microCT; near infrared laser; root resorption