title: High-intensity Nd:YAG laser accelerates bone regeneration in calvarial defect models.
abstract: High-power pulsed lasers have been recently regarded to be anabolic to bone, but in vivo evidence is still lacking. This study aimed to investigate the capacity of bone repair using a high-power, Q-switched, pulsed, neodymium-doped yttrium aluminium garnet (Nd:YAG) laser, using bilateral calvarial defect models having non-critical sized, 5 mm (rat) or 8 mm (rabbit) diameter. One of the bilateral defects, which were all filled with collagen sponge or left empty, was irradiated with a Nd:YAG laser once every 2 days for 2 weeks at a constant total fluence rate (344 J/cm(2) ), output power (0.75 W), pulse repetition rate (15 pps) and wavelength (1064 nm) and examined for the laser effect. The same experimental scheme was designed using a rabbit calvarial defect model implanted with sponge, which was explored for the dose effect of output power at 0.75 and 3 W with the same quantities of the other parameters. New bone formation was evaluated by micro-computed tomography-based analysis and histological observation at 4 weeks after surgery. Laser irradiation significantly increased new bone formation by approximately 45%, not only in the sponge-filled defects of rats but also when the defects were left empty, compared to the non-irradiated group. Consistently, both doses of output power (0.75 and 3 W) enhanced new bone formation, but there was no significant difference between the two doses. This study is one of the first to demonstrate the beneficial effect of Nd:YAG lasers on the regeneration of bone defects which were left empty or filled with collagen sponge, suggesting its great potential in postoperative treatment targeting local bone healing.
authors.affiliation: New York Seoul Dental Hospital, Seoul, Republic of Korea.
authors.forename: Kwansik
authors.initials: K
authors.lastname: Kim
authors.affiliation: Dental Research Institute, Seoul National University, Seoul, Republic of Korea.
authors.forename: In Sook
authors.initials: IS
authors.lastname: Kim
authors.affiliation: Dental Research Institute, Seoul National University, Seoul, Republic of Korea.
authors.forename: Tae Hyung
authors.initials: TH
authors.lastname: Cho
authors.affiliation: Department of Chemical and Biochemical Engineering, Dongguk University, Seoul, Republic of Korea.
authors.forename: Young-Kwon
authors.initials: YK
authors.lastname: Seo
authors.affiliation: Dental Research Institute, Seoul National University, Seoul, Republic of Korea.|Department of Oral and Maxillofacial Surgery, School of Dentistry, Seoul National University, Brain Korea 21 Program for Leading Universities and Students, Seoul, Republic of Korea.
authors.forename: Soon Jung
authors.initials: SJ
authors.lastname: Hwang
mesh_terms: D000535:Aluminum; D000818:Animals; D001861:Bone Regeneration / Q000528:radiation effects*; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000528:radiation effects*; D003094:Collagen / Q000737:chemistry; D017102:Fracture Healing; D021621:Imaging, Three-Dimensional; D007834:Lasers; D053844:Lasers, Solid-State; D008297:Male; D009354:Neodymium; D011817:Rabbits; D051381:Rats; D055114:X-Ray Microtomography; D014965:X-Rays; D015019:Yttrium
chemical_list: C503779:yttrium-aluminum-garnet; D009354:Neodymium; D015019:Yttrium; D003094:Collagen; D000535:Aluminum
keywords: Nd:YAG laser; bone regeneration; calvarial defect; collagen sponge; high intensity; high power