Fig. 1

Distribution of PRX1⁺ cells in tooth germ, incisors, and molars. a H&E staining (a1, a4) and distribution of PRX1⁺ cells in the tooth germ of first molar of the maxillary (a2, a3) and mandible (a5, a6) at 14.5 days of the embryo (E 14.5). The edge of the tooth germ epithelium is outlined with a dotted line. PRX1⁺ cells are concentrated in the mesenchyme of the tooth germ and are completely absent in the epithelium (a2, a3, a5, and a6) (n = 4). b Distribution of PRX1⁺ cells in M1 and incisor of mice at 1 week. White arrowheads: high concentrations of PRX1⁺ cells in the pulp cavity. In M1, PRX1⁺ cells appear in the pulp cavity, especially in odontoblasts (b1, b2). In incisor, they are primarily present in the stem cell niche area near the buccal and lingual cervical loop (b3, b4). In addition, high concentrations are present in the alveolar bone around M1 and incisor (n = 4). c Comparison of distribution patterns of PRX1⁺ cells in M1-M3 of one-week-old mice. c1 H&E staining of M1-M3. Numerous PRX1⁺ cells expressing tdTomato fluorescence are distributed in the pulp cavity of M1 (c2, c3) and the number of positive cells decreases in M2 (c4, c5). However, it is not observed in the dental papilla of M3 (c6, c7) (n = 4). epi epithelium, mes mesenchyme, od odontoblast, am ameloblast, dp dental pulp, HERS Hertwig’s epithelial root sheath, laCL labial cervical loop, liCL lingual cervical loop, sr stellate reticulum, iee inner enamel epithelium. Scale bar: 100 μm