Effect of ovariectomy on bone remodeling adjacent to hydroxyapatite-coated implants in the tibia of mature rats.
OBJECTIVE
The purpose of this study was to examine the effects of estrogen deficiency on bone remodeling adjacent to implants in the tibia of mature rats.


METHODS
Hydroxyapatite-coated implants were placed bilaterally in the proximal metaphysis of the tibia of 18 female Wistar rats (48 weeks old), and ovariectomy was performed 168 days later. As a control, sham ovariectomy was performed in a similar group of 18 rats. Six animals from each group were killed at 28, 84, and 168 days after ovariectomy. Undecalcified sections were prepared, and changes in the bone tissue around the implants were evaluated histologically. Histomorphometric measurements were made with a computer-based image analyzer to quantify the unit bone mass around each implant and the amount of implant-bone contact.


RESULTS
In the cortical bone area, ovariectomy induced only a slight decrease in bone contact with the implant, compared with that in the sham-operated rats. However, both the bone volume around the implant and implant-bone contact were significantly decreased in the cancellous bone area in ovariectomized rats compared with the sham-operated rats.


CONCLUSIONS
Thinning of the bone trabeculae holding dental implants may occur with estrogen deficiency.
Department of Oral and Maxillofacial Surgery, School of Dentistry, Dalian Medical University, China.
J
J
Pan
T
T
Shirota
K
K
Ohno
K
K
Michi
D000818:Animals; D015519:Bone Density; D016723:Bone Remodeling; D020099:Coated Materials, Biocompatible; D003758:Dental Implantation, Endosseous; D004195:Disease Models, Animal; D017886:Durapatite; D004967:Estrogens / Q000172:deficiency; D005260:Female; D006801:Humans; D016348:Osseointegration; D015663:Osteoporosis, Postmenopausal / Q000503:physiopathology*; D010052:Ovariectomy; D010053:Ovary / Q000502:physiology; D019736:Prostheses and Implants; D051381:Rats; D017208:Rats, Wistar; D018709:Statistics, Nonparametric; D013977:Tibia / Q000473:pathology
D020099:Coated Materials, Biocompatible; D004967:Estrogens; D017886:Durapatite