Department of Orthodontics, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai, China.
J Craniofac Surg. 2021 Oct 1;32(7):2562-2565. doi: 10.1097/SCS.0000000000007798.
The goal of this study was to identify bone defects of critical size in C57BL/6 mouse mandibles.
Twenty-four male mice were included in this study. All mice underwent surgeries on their left mandibles. Mandibular defects of 1.0 mm (n = 8), 1.6 mm (n = 8), and 2.3 mm (n = 8) were created. For the investigation of bone healing after an 8-week period, micro-computed tomography scans and histomorphology were performed.
Mandibular bone nonunions were seen 0/8 in the 1.0-mm group, 6/8 in the 1.6-mm group, and 8/8 in the 2.3-mm group. The outcome of micro-computed tomography showed that, after 8 weeks, the bone mineral density and the bone volume to total volume ratio were significantly different among the 3 groups. The defect gaps in the nonunion 1.6- and 2.3-mm groups were filled with connective tissue, and no obvious bone formation was found. Additionally, in quantitative analysis, according to the new bone fill calculations, the percentages were 91.85% ± 8.03% in the 1.0-mm group, 59.84% ± 20.60% in the 1.6-mm group, and 15.36% ± 8.28% in the 2.3-mm group, which indicated statistically significantly lower defect healing in the 2.3-mm group.
The creation of 2.3-mm mandibular defects produces osseous nonunion in C57BL/6 mice.
本研究的目的是确定 C57BL/6 小鼠下颌骨的临界大小骨缺损。
本研究纳入了 24 只雄性小鼠。所有小鼠均接受了左侧下颌骨手术。分别创建了 1.0mm（n=8）、1.6mm（n=8）和 2.3mm（n=8）的下颌骨缺损。为了研究 8 周后骨愈合情况，进行了 micro-CT 扫描和组织形态学检查。
1.0mm 组未见下颌骨骨不连 0/8，1.6mm 组 6/8，2.3mm 组 8/8。micro-CT 结果显示，8 周后，3 组的骨密度和骨体积/总体积比有显著差异。1.6mm 和 2.3mm 组的未愈合缺损间隙充满结缔组织，未见明显骨形成。此外，在定量分析中，根据新骨填充计算，1.0mm 组的百分比为 91.85%±8.03%，1.6mm 组为 59.84%±20.60%，2.3mm 组为 15.36%±8.28%，表明 2.3mm 组的缺损愈合明显较低。
在 C57BL/6 小鼠中，创建 2.3mm 的下颌骨缺损会导致骨不连。
