[Histological study of miniscrew implanted in lower mandibles of juvenile and adult Beagle dogs].
OBJECTIVE
To examine the histological discrepancies between juvenile and adult Beagle dogs at different concrescence times after miniscrew implants.


METHODS
Miniscrew implants were performed in six juvenile Beagle dogs and six adult Beagle dogs. The space between the fourth premolar root and first molar root, and the spaces in distal and mesial of M1 root were picked up for the implants of the 48 miniscrews. The lower jaw specimens including the miniscrews were harvested 3 and 12 weeks after the implants for the histological examinations and bone implant contact (BIC) calculations.


RESULTS
There was no miniscrew falling off or becoming loose. The miniscrews had favorable biological consistencies with the tissues around them. The osteoblasts and osteoclasts showed active functions in the peri-bones of the minisrews. The BIC became higher when the healing time was prolonged. The juvenile Beagle dogs had lower BIC than the adults 3 weeks after the implants. But the BIC of the juvenile dogs surpassed the adults 12 weeks after the implants.


CONCLUSIONS
The osseointegration of the miniscrews is hindered by the poorer bone quality of the juvenile Beagle dogs. But the early osseointegration deficiency can be made up by the rapid development and growth of the bones of the juvenile dogs.
Wang
Yong
Y
Department of Orthodontics, West China Stomatology Hospital, Sichuan University, Chengdu 610041, China.
Jia
Ying
Y
Zhang
Jun-Mei
JM
Wang
Zhi-Qiang
ZQ
Wang
Yu
Y
Yang
Pu
P
Tang
Tian
T
Wu
Xiu-Ping
XP
Zheng
Lei-Lei
LL
Zhao
Zhi-He
ZH
D000367:Age Factors; D000539:Alveolar Process / Q000473:pathology; D000818:Animals; D001863:Bone Screws; D003758:Dental Implantation, Endosseous / Q000379:methods; D004285:Dogs; D020007:Implants, Experimental; D008334:Mandible / Q000473:pathology*; D008904:Miniaturization; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D016382:Orthodontic Appliance Design; D016348:Osseointegration / Q000502:physiology*