1.Root canal curvature of anterior teeth in the Han nationality in Shaanxi province
Xili WENG ; Shibin YU ; Shouliang ZHAO
Journal of Practical Stomatology 2000;0(06):-
Objective: To investigate the root canal curvatures of anterior teeth in the Han nationality in Shaanxi province.Methods:392 permanent anterior teeth were examined by indirect digital radiography both from labiolingual and mesiodistal directions according to Schneider method, root canal curvatures were analyzed by electronic rule.Results:Root canals of the anterior teeth were mainly of type I. High rate of root canal curvature was found in maxillary canines (68.5%), and most of curves were in the apical third. There was a relationship between the root canal curvatures of maxillary canine and age(P=0.03). Conclusion:Root canal curvatures of maxillary canine are complicated,especially in maxillary canines. The root canal curvatures of maxillary canine decreased with aging.
2.The effects of estrogen on the degenerative changes of rat condylar cartilage and subchondral bone
Tao YE ; Dongliang SUN ; Xili WENG ; Mian ZHANG ; Hongxu YANG ; Yichao LIU ; Shibin YU
Journal of Practical Stomatology 2018;34(1):5-10
Objective: To study the effects of estrogen on the degenerative changes of condylar cartilage and subchondral bone in rats. Methods: 18 female SD rats aged 6 weeks were divided into control(C),unilateral anterior cross-bite(UAC) and UAC treated with estrogen(UAC + E) groups(n = 6). UAC metal prosthesis was cemented to the left incisors of maxilla and mandible of the rats in group UAC and UAC + E. Rats in UAC + E group were given pexitoneal injection of 80 μg 17β-estradiol per day. The rats in group C were untreated. Animal were sacrificed at the 4th weeks. The micro-structure of subchondral bone was observed by Micro-CT scanning. HE staining,Safranin O staining,immunohistochemical staining,TUNEL staining and TRAP staining for the observation of pathological changes of histomorphology,extracellular matrix,chondrocyte apoptosis in condylar cartilage,and osteoclasts number in subchondral bone. Results: UAC and UAC + E group showed evident osteoarthritis(OA)-like lesions. Compare with UAC group,there was a significant decrease in the expression of proteoglycan(P < 0. 05),type Ⅱ collagen(P < 0. 01),and a significant increase in the number of apoptotic chondrocytes(P < 0. 01) in UAC + E group. As for subchondral bone,the BV/TV,Tb. Th parameters in C and UAC + E groups were significant higher than in UAC group(P < 0. 01),while the BS /BV,Tb. N,Tb. Sp parameters and the osteoclasts number in C and UAC + E groups were significant fewer than in UAC groups(P < 0. 01). There was no significant difference in bone ultra-parameters and osteoclasts number between C and UAC + E groups(P> 0. 05). Conclusion: In the model of rat TMJOA induced by unilateral anterior crossbite prosthesis,supra-physiological level of estrogen can reverse bone loss in subchondral bone,but accelerate the degradation of condylar cartilage.