The correlation between neovascularization and bone formation in the condyle during forward mandibular positioning.
The aim of the present study was to investigate the temporal pattern of expression of VEGF (Vascular Endothelial Growth Factor) and new bone formation in the condyle during forward mandibular positioning. The importance of vascularization during endochondral ossification was investigated during natural growth of the condyle and compared to that after forward mandibular positioning. The goal was to further our understanding of the cellular responses during functional appliance therapy with a view to extending the experiment into maturity. One hundred and fifty 35 days old Sprague-Dawley rats, 100 fitted with a bite-jumping appliance and 50 untreated, were divided into 10 groups. One group was sacrificed on each of experimental days 3, 7, 14, 21, 30, 33, 37, 44, 51 and 60 respectively. Sagittal sections were cut and stained with VEGF antibodies and Periodic acid and Schiff's reagent (PAS). Each section was quantitatively analyzed with a computer assisted analyzing program and the temporal sequence of expression of VEGF and new bone formation during natural growth and after mandibular forward positioning was compared. There was significant increase in both vascularization and mandibular bone growth upon forward mandibular positioning and the highest amount of both were expressed in the posterior region of the condyle. The highest acceleration of vascularization preceded that of new bone formation. Thus, forward mandibular positioning was found to solicit a sequence of cellular events leading to increased vascularization and subsequently new bone formation resulting in enhanced condylar growth.
Rabie
A B M
AB
Hard Tissue Research, Faculty of Dentistry, The University of Hong Kong, SAR, China. rabie@hkusua.hku.hk
Leung
F Y C
FY
Chayanupatkul
A
A
Hägg
U
U
D000704:Analysis of Variance; D000818:Animals; D019902:Chondrocytes / Q000473:pathology; D016228:Endothelial Growth Factors / Q000032:analysis; D005260:Female; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins / Q000032:analysis; D008222:Lymphokines / Q000032:analysis; D008334:Mandible / Q000254:growth & development / Q000473:pathology / Q000502:physiology; D008335:Mandibular Condyle / Q000098:blood supply / Q000254:growth & development / Q000502:physiology*; D018919:Neovascularization, Physiologic / Q000502:physiology*; D016382:Orthodontic Appliance Design; D017289:Orthodontic Appliances, Functional; D010012:Osteogenesis / Q000502:physiology*; D010503:Periodic Acid-Schiff Reaction; D020033:Protein Isoforms / Q000032:analysis; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013223:Statistics as Topic; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D036341:Intercellular Signaling Peptides and Proteins; D008222:Lymphokines; D020033:Protein Isoforms; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors