H&E staining of the dentin-pulp complex in 3- and 6-month-old mice (A–H) and biglycan immunostaining of predentin/dentin in 3-month-old mice (I–L). At postnatal 3 months, the Dspp-KO mice (B) had wider predentin (solid arrow), uncoalescent calcospherites (hollow arrow) and an irregular dentin-predentin border compared with the WT mice (A). The Dspp-KO/D452A-Tg mice (D) showed dentin abnormalities similar to those of the Dspp-KO mice (B). The dentin of the Dspp-KO/normal-Tg (C) mice resembled that of the WT mice (A). At postnatal 6 months, the dentin-pulp structures in the Dspp-KO/normal-Tg (G) mice resembled those of the WT mice (E), while the Dspp-KO/D452A-Tg mouse teeth (H) resembled those of the Dspp-KO mice (F). Bar: A–H = 50 μm. In the biglycan immunostaining of predentin/dentin, the predentin stained by the anti-biglycan antibody (brown color) in the WT mice (I) and Dspp-KO/normal-Tg mice (K) was thin, smooth and evenly distributed, while the predentin in the Dspp-KO mice (J) and Dspp-KO/D452A-Tg mice (L) was wider and unevenly distributed. Bar: I–L = 100 μm.