Micro-CT analysis of the tooth-alveolar bone complex of BMP9-KO mice. (A) Representative images of the first molar. (B) The representative image of the methods used to quantitatively measure the parameters listed in (C–I). Yellow arrows indicated root length, red indicated dentin thickness, and green indicated height of alveolar ridge. The area highlighted in red marked the alveolar bone ROI, the yellow area marked the enamel ROI, and the blue area marked the dentin ROI. Quantitative analysis of (C) root length, (D) dentin thickness, (E) height of alveolar ridge, (F) trabecular thickness, (G) BV/TV, (H) bone mineral density of alveolar bone, and (I) enamel and dentin mineral density. Data were presented as mean ± standard deviation (SD); *P < 0.05, when compared with those of the wild-type littermates. ROI, region of interest; Micro-CT, micro-computed tomography; BV/TV, bone volume fraction. Color images are available online.