Figure 1
Cervical tongues determine the root pattern. (a–d) Cusp (occlusal view) and root pattern (apical view) in first molars of mandible and maxilla from PN (postnatal day)14 mouse (a,b) and PN21 rat (c,d). Alveolar sockets reveal the number of roots which concurrent with the number of roots depicted in apical view. Notice that mouse and rat share the same number of cusp in their first molars but their root numbers are different. (e,f) Localization of E-Cadherin protein in the dental epithelium of whole-mount first molars of mouse E (embryonic day)14, 15, 16 and 17; and PN0, 2, 4, 6 and 9 visualizes cervical tongues (arrowheads) from the apical view. Two and three well-developed cervical tongues are formed in mouse mandibular and maxillary first molar, respectively (arrowheads in e and f). Buccal cervical tongues at E17 and PN0 merged together to form single well-developed cervical tongue at PN4 in maxilla (1–1, 1–2 and 1 in f). (g,h) Localization of E-Cadherin protein in the dental epithelium of whole-mount first molars of rat E16, 17, 18 and 19; and PN0, 2, 4, 6 and 9 visualizes cervical tongues (arrowheads) from the apical view. Four and five well-developed cervical tongues are formed in rat mandibular and maxillary first molar, respectively (arrowheads). Notice doublet of buccal cervical tongues in maxilla at PN0 form single cervical tongue at PN2 (2–1, 2–2 and 2 in h). Notice that the distance between buccal and lingual cervical loops in cuspal area increase from E16 to PN4 and decreased from PN6 (asterisks in e and g). B-anid: buccal anteroconid, L-anid: lingual anteroconid, Prd: protoconid, Med: metaconid, Hyd: hypoconid, End: entoconid, Hld: hypoconulid. For maxilla, B-An: buccal anterocone, L-An: lingual anterocone, Ans: anterostyle, Pa: paracone, Pr: protocone, Ens: enterostyle, Me: metacone, Hy: hypocone. Scale bar: a–h, 500 µm.
