Cyclooxygenase-2 activity is essential for the osseointegration of dental implants.
The aim of this study was to examine the effect of cyclooxygenase (COX)-2 on bone response after the placement of implants in the femurs of mice. titanium implants 1.0mm in diameter were placed into the middle of the femurs of 9-week-old male COX-2 wild-type (COX-2(+/+)) and knockout (COX-2(-/-)) mice. For RNA analysis, the mice were killed 0, 1, 2, 4, 7 and 56 days after implantation. RNA was extracted from the bone surrounding the implants. For histological analysis, the mice were killed 4 and 8 weeks after treatment, and undecalcified sections were prepared. Contact microradiography was performed, and the sections were stained with 1% toluidine blue for histological examination. Histomorphometric measurements were obtained with a computer-based image analyser to quantify bone newly formed around the implant and the rate of implant-bone contact. Expression of COX-2 and osteocalcin mRNA was induced in bone surrounding implants in COX-2(+/+) mice, but not in COX-2(-/-) mice. In cortical bone, the implant surface was in direct contact with newly formed bone lamellae in COX-2(+/+) mice; new bone formation was minimal in COX-2(-/-) mice. These results suggest that COX-2 plays an essential role in osseointegration and provide evidence that COX-2-selective non-steroidal anti-inflammatory drugs may interfere with osseointegration clinically.
Chikazu
D
D
Department of Oral-Maxillofacial Surgery, Dentistry and Orthodontics, The University of Tokyo Hospital, Bunkyo, Tokyo, Japan. chikazu-ora@umin.ac.jp <chikazu-ora@umin.ac.jp>
Tomizuka
K
K
Ogasawara
T
T
Saijo
H
H
Koizumi
T
T
Mori
Y
Y
Yonehara
Y
Y
Susami
T
T
Takato
T
T
D000818:Animals; D004396:Coloring Agents; D051546:Cyclooxygenase 2 / Q000032:analysis* / Q000235:genetics; D015921:Dental Implants; D003764:Dental Materials; D005269:Femur / Q000201:enzymology* / Q000473:pathology / Q000601:surgery; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D008852:Microradiography; D016348:Osseointegration / Q000502:physiology*; D015675:Osteocalcin / Q000032:analysis / Q000235:genetics; D010012:Osteogenesis / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis; D013997:Time Factors; D014025:Titanium; D014048:Tolonium Chloride
D004396:Coloring Agents; D015921:Dental Implants; D003764:Dental Materials; D012333:RNA, Messenger; D015675:Osteocalcin; D014048:Tolonium Chloride; D014025:Titanium; D051546:Cyclooxygenase 2