Long-term changes in trabecular structure of aged rat alveolar bone after ovariectomy.
OBJECTIVE
Trabecular structural changes in the jaw after long-term estrogen deficiency are not well understood. Therefore, we sought to observe the changes in rat alveolar bone for 1 year.


METHODS
Six-month-old female rats were ovariectomized (OVX) or underwent a sham operation. After 1 year, bone histomorphometry and a node-strut analysis were performed on the interradicular septum of the mandibular first molar by using micro computed tomography and confocal laser scanning microscopy. Statistical analysis was carried out by using analysis of variance.


RESULTS
The alveolar trabeculae of rats in the sham group had network structures, whereas the trabeculae of rats in the OVX group became fragmented. The trabecular bone volume, number, and thickness in the OVX group were significantly lower than those found in the sham group, and the trabecular separation was 4-fold higher in the OVX group than in the sham group. Bone resorptive and formative activity appeared to be moderately higher in the OVX group than in the sham group, but only the difference in bone formation was of statistical significance.


CONCLUSIONS
By 1 year after ovariectomy, bone loss and trabecular fragmentation had occurred in the rat mandibular alveolar bone.
Tanaka
Mikako
M
Department of Tissue Regeneration and Reconstruction, Division of Removable Prosthodontics, Section for Oral Life Science, Graduate School of Medical and Dental Science, Niigata University, 5274, Gakkocho-dori 2, Niigata 951-8514, Japan.
Toyooka
Eiichi
E
Kohno
Shoji
S
Ozawa
Hidehiro
H
Ejiri
Sadakazu
S
D000375:Aging / Q000473:pathology* / Q000502:physiology; D000539:Alveolar Process / Q000473:pathology*; D000704:Analysis of Variance; D000818:Animals; D015519:Bone Density / Q000502:physiology; D001862:Bone Resorption / Q000473:pathology; D004967:Estrogens / Q000172:deficiency; D005260:Female; D007091:Image Processing, Computer-Assisted; D008334:Mandible / Q000473:pathology; D008852:Microradiography; D018613:Microscopy, Confocal; D010012:Osteogenesis / Q000502:physiology; D010052:Ovariectomy; D010053:Ovary / Q000502:physiology*; D011897:Random Allocation; D051381:Rats; D011916:Rats, Inbred F344; D013997:Time Factors; D014057:Tomography, X-Ray Computed
D004967:Estrogens