Fig. 5

Cilk1-deficient tooth germs form fully calcified teeth. a, b Fully calcified teeth formed from mandibular E14.5 developing molars of wild-type (WT) and Cilk1^−/− mice within the renal subcapsular layer over a 4-week period. c, d Micro-CT reconstructions showing distinct differences in tooth pattern between wild-type and Cilk1^−/− mice. In wild-type samples, tooth size progressively decreases from left to right, whereas in Cilk1^−/− calcified teeth, the central tooth is the largest. Wild-type samples show the first, second, and third molars (M1, M2, M3) from left to right, whereas Cilk1^−/− samples show the diastemal supernumerary tooth (R2), M1, and M2. e, f Comparative images showing that root (asterisks) length appears shorter in Cilk1^−/− calcified teeth than in wild-type teeth. g, h Micro-CT sections demonstrating well-formed enamel (white arrows), dentin (white arrowheads), and surrounding bone (yellow arrowheads) in both wild-type and Cilk1^−/− teeth. i, j Histological analysis confirming the presence of enamel space (ES), dentin (D), dentinal tubules, predentin (PD), and odontoblasts (OB) in both genotypes. k–p Representative images of Krt14-Cre;Cilk1^fl/fl mice at PN 8 and PN 4 weeks, showing organic enamel (black arrows) and secretory ameloblasts (black arrowheads) at PN 8 and fully mineralized enamel (yellow arrows) at PN 4 weeks, similar to Krt14-Cre;Cilk1^fl/+ mice. q Crown volume measurements of calcified teeth indicate that the central tooth in Cilk1^−/− teeth is the largest, supporting the identification of the left tooth as R2. r The relative crown volume of R2 to M1 (R2/M1 ratio) in Cilk1^−/− teeth is significantly smaller than the M1 to M2 volume ratio (M1/M2) in wild-type teeth. s Root length is shorter in Cilk1^−/− teeth compared to wild-type controls. Scale bars: a–h: 250 μm, i, j: 50 μm, k, l: 300 μm, m, n: 200 μm. **P < 0.01