Acute effects of ovariectomy on wound healing of alveolar bone after maxillary molar extraction in aged rats

Abstract

Acute effects of ovariectomy on the bone wound healing processes after maxillary molar extraction in aged rats were examined by means of quantitative scanning electron microscopy (SEM), backscattered electron image (BSE) analysis and energy-dispersive X-ray (EDX) microanalysis. Six-month-old female rats underwent either sham operation or bilateral ovariectomy, and 7 days postoperatively, the maxillary first molars were extracted. On post-extraction days 7, 30 and 60, the dissected maxillary bone surfaces were examined by SEM to reveal the bone formative and resorptive areas around the extracted alveolar sockets. In addition, the resin-embedded maxillae were micromilled in the transverse direction through the extracted alveolar sockets, and the newly-formed bone mass on the buccal bone surfaces and within the extracted sockets was examined by BSE analysis. Compared with sham-operated controls, the extent of newly-formed bone mass on the buccal bone surfaces in OVX rats was significantly decreased, due to increased bone resorption. On the other hand, new bone formation within the extracted sockets was similar in the experimental groups. In EDX microanalysis of these newly-formed bone matrices, both Ca and P weight % and Ca/P molar ratio were similar in the experimental groups. Our results suggest that 1) acute estrogen deficiency induced by ovariectomy stimulates sustained bone resorption, but has less effect on bone formation, and 2) bone wound healing after maxillary molar extraction within extracted alveolar sockets is not significantly delayed by ovariectomy, but bony support by newly-formed bone mass on the maxillary bone surfaces at the buccal side of the extracted sockets is significantly decreased, due to increased bone resorption.

Copyright 2001 Wiley-Liss, Inc.