Histological and Biochemical Investigation of the Effects of Low Intensity Pulsed Ultrasound on Orthodontic Tooth Movement

Abstract

Objective: The aim of this study is to investigate the effects of low intensity pulsed ultrasound on orthodontic tooth movement in rats. Methods: For this study, 40 12-week-old adult male Wistar albino rats from the Animal Laboratory at Adnan Menderes University, Faculty of Medicine, were used. Rats were divided into four groups of ten. Group 1 was the untreated control group. In group 2, an orthodontic spring was used to move teeth. In groups 3 and 4, orthodontic treatment was combined with low intensity pulsed ultrasound at 16 J/cm2 or 48 J/cm2, respectively, for 14 days. Tooth movement was measured on day 14. Serum bone alkaline phosphatase (BALP) and C-telopeptide of type I collagen (CTX-I) levels were analyzed biochemically. The number of osteoclasts, osteoblasts and inflammatory cells, capillary density and new bone formation was determined histologically. Receptor activator of nuclear factor-kappa B ligand (RANKL), osteoprotegerin (OPG), vascular endothelial growth factor (VGEF) and transforming growth factor-β (TGF-β) were assessed using immunohistochemical staining. Results: BALP and CTX-I levels in group 4 were significantly higher than for group 1. Tooth movement and the number of osteoclasts, inflammatory cells, and capillary density in group 4 were significantly greater than for group 2. The intensity levels of RANKL and OPG in group 4 were significantly greater than for group 2. Conclusion: Ultrasound is noninvasive application and a promising therapy for accelerating bone remodeling during orthodontic tooth movement.