title: Vascular endothelial growth factor expression and bone formation in posterior glenoid fossa during stepwise mandibular advancement.
abstract: This study assessed the amount of vascular endothelial growth factor (VEGF) expression and related the findings to new bone formation in the posterior glenoid fossa during stepwise mandibular advancement. A total of 250 female Sprague-Dawley rats, 35 days old, were randomly divided into 10 groups, each including 5 control and 20 experimental rats. Within each group, 10 experimental rats were fitted with functional appliances with a 1-step advancement of 3.5 mm. Another 10 were fitted with stepwise appliances with an initial advancement of 2 mm and a subsequent increase to 3.5 mm on day 30. The rats in the experimental groups were killed on days 3, 7, 14, 21, 30, 33, 37, 44, 51, and 60, respectively. The matched controls were killed on the same time points. Sections (7 microm) were cut through the glenoid fossa sagittally and stained with anti-VEGF antibody. VEGF expression in the posterior glenoid fossa was evaluated with a computer-assisted image-analyzing system. Both VEGF expression and new bone formation were greater in the experimental rats than in the controls. During stepwise advancement, initial VEGF expression was less than that of 1-step advancement, but the second advancement elicited another peak on day 44. New bone formation was also less than that of 1-step advancement during early stages of stepwise advancement but then began to increase from day 37 onward. The maximum increase was observed on day 60. Stepwise advancement of the mandible delivers mechanical stimuli that produce a series of tissue responses that lead to increased vascularization and bone formation.
authors.affiliation: Faculty of Dentistry, Department of Orthodontics, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Lily
authors.initials: L
authors.lastname: Shum
authors.forename: A B M
authors.initials: AB
authors.lastname: Rabie
authors.forename: Urban
authors.initials: U
authors.lastname: Hägg
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D004396:Coloring Agents; D005260:Female; D007091:Image Processing, Computer-Assisted; D019186:Mandibular Advancement / Q000295:instrumentation / Q000379:methods*; D017289:Orthodontic Appliances, Functional; D010012:Osteogenesis / Q000502:physiology*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013314:Stress, Mechanical; D013701:Temporal Bone / Q000473:pathology / Q000503:physiopathology*; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis*
chemical_list: D004396:Coloring Agents; D042461:Vascular Endothelial Growth Factor A