Tisssue responses in corticotomy- and osteotomy-assisted tooth movements in rats: histology and immunostaining.
BACKGROUND
The purpose of this histologic study was to examine underlying cellular responses to corticotomy- and osteotomy-assisted tooth movements.


METHODS
Thirty-six rats were divided into 5 groups: corticotomy-assisted tooth movement (CO + TM), sham corticotomy without tooth movement (CO alone), osteotomy-assisted tooth movement (OS + TM), sham osteotomy without tooth movement (OS alone), and unassisted tooth movement (TM alone). Standard orthodontic springs were activated to produce mesial tooth movement. The rats were killed at 3, 21, and 60 days after activation for osteoclast and blood vessel counts, and immunostaining with proliferating cell nuclear antigen (PCNA), transforming growth factor beta 1 (TGF beta 1), vascular endothelial growth factor (VEGF), and osteocalcin were performed.


RESULTS
The CO + TM group had significantly more osteoclasts at 3 days (P <0.005) compared with the OS + TM group. The alveolar bone surrounding the dental roots was replaced with multicellular tissue at 21 days in the CO + TM group but was intact in the OS + TM group with the exception of a distal distraction site. At day 21, immunostaining with PCNA, TGF beta 1, VEGF, and osteocalcin occurred at the mesial border of bone in the CO + TM group, whereas a diffuse pattern was observed in the distal distraction sites at 21 and 60 days in the OS + TM group.


CONCLUSIONS
Corticotomy-assisted tooth movement produced transient bone resorption around the dental roots under tension; this was replaced by fibrous tissue after 21 days and by bone after 60 days. Osteotomy-assisted tooth movement resembled distraction osteogenesis and did not pass through a stage of regional bone resorption.
Wang
Lei
L
Department of Oral and Maxillofacial Surgery, Fourth Military Medical University, School of Stomatology, Xi'an, China.
Lee
Won
W
Lei
De-Lin
DL
Liu
Yan-Pu
YP
Yamashita
Dennis-Duke
DD
Yen
Stephen L-K
SL
D000539:Alveolar Process / Q000378:metabolism* / Q000601:surgery; D000704:Analysis of Variance; D000818:Animals; D001861:Bone Regeneration / Q000502:physiology*; D001862:Bone Resorption / Q000378:metabolism*; D007150:Immunohistochemistry; D008137:Longitudinal Studies; D008297:Male; D008437:Maxilla / Q000378:metabolism* / Q000601:surgery; D015675:Osteocalcin / Q000378:metabolism; D010012:Osteogenesis / Q000502:physiology*; D010027:Osteotomy / Q000379:methods; D010486:Periapical Tissue / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution; D014087:Tooth Movement Techniques; D053773:Transforming Growth Factor beta1 / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D018809:Proliferating Cell Nuclear Antigen; D053773:Transforming Growth Factor beta1; D042461:Vascular Endothelial Growth Factor A; D015675:Osteocalcin