Objective:To investigate the microstructure changes of alveolar bone in diabetic rats by micro-CT.Methods:Male Sprague-Dawley rats were randomly divided into control group and diabetes group

with 4 rats ineach group. The rats in the diabetes group were given intraperitoneal injection of 55 mg/kg streptozotocin. The ratswere sacrificed after 12 weeks of feeding

and micro-CT scan and HE staining were performed for the maxillarybone.Results:HE staining showed marked absorption of the edge of alveolar bone

disordered arrangement of peri-odontal membrane fibers

and marked inflammatory ceils infiltration in the gingival epithelium in the diabetes group.Compared with the control group

the diabetes group had a significant increase in distance from the cemento-enameljunction to the alveolar bone crest（P < 0.05）. Micro-CT analysis showed a significant reduction in Tb.N value（P <0.01） and a significant increase in Tb.sp value in the diabetes group（P < 0.05）. Micro-CT three-dimensional imagereconstruction showed alveolar bone absorption in the diabetes group.Conclusion:Marked alveolar bone injury isobserved in rats with STZ-induced diabetes

and micro-CT technique displays the microstructure changes of peri-odontal bone tissue.