Bone reactions around hydroxyapatite-coated implants in ovariectomized rats.
OBJECTIVE
The purpose of this study was to investigate bone reaction after implantation in an estrogen-deficient state by examining the changes in bone reactions within tissue surrounding implants in ovariectomized rats.


METHODS
Ninety-six 12-week-old female Wistar rats were used in the study; they were divided into 2 groups, an ovariectomized group and a sham-operated group. Hydroxyapatite-coated implants were placed in the proximal metaphyses of the tibiae 21 days after surgery. The tibiae were examined histologically by undecalcified sections at various intervals from 7 to 168 days after surgery.


RESULTS
In the cortical bone area of the ovariectomized rats, the procedure did not induce any apparent changes in bone volume around the implant or in bone contact with the implant in comparison with the sham-operated rats. In contrast, both bone volume around the implant and contact of the implant with new bone were significantly decreased in the cancellous bone area in the ovariectomized rats in comparison with the sham-operated rats.


CONCLUSIONS
Ovariectomy did not seriously affect bone healing after the placement of implants in cortical bone areas, but it reduced the bone contact ratio and the bone in the cancellous bone area.
First Department of Oral and Maxillofacial Surgery, School of Dentistry, Showa University, Tokyo, Japan.
M
M
Motohashi
T
T
Shirota
Y
Y
Tokugawa
K
K
Ohno
K
K
Michi
A
A
Yamaguchi
D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D015519:Bone Density; D001842:Bone and Bones / Q000502:physiology; D020099:Coated Materials, Biocompatible; D017886:Durapatite; D004967:Estrogens / Q000172:deficiency* / Q000502:physiology; D005260:Female; D020007:Implants, Experimental; D007527:Isoenzymes / Q000378:metabolism; D016348:Osseointegration / Q000502:physiology*; D010010:Osteoclasts / Q000201:enzymology; D010012:Osteogenesis / Q000502:physiology; D010052:Ovariectomy; D051381:Rats; D017208:Rats, Wistar; D018709:Statistics, Nonparametric; D000071681:Tartrate-Resistant Acid Phosphatase; D014945:Wound Healing / Q000502:physiology
D020099:Coated Materials, Biocompatible; D004967:Estrogens; D007527:Isoenzymes; D017886:Durapatite; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase