Enamel, dentine and pulp in talon primary maxillary central incisors: a histomorphometric study.

To examine whether a talon incisor has an abnormal shape due to excess of dental hard tissues or pulp. Two bilateral primary maxillary central incisors with talon cusp and a supernumerary mesiodens were removed from a 6-year-old boy. Histologically, 7 undecalcified cross sections (70 microm) were harvested from each talon tooth and from two regular primary central incisors of another child. Microradiographs of the sections were prepared and examined for enamel width, dentin width, pulp tissue area, and crown size (mesio-distal, labio-palatal) using Image Analysis. No association to other developmental disorders was observed. The mean width of the enamel and dentin was similar in the talon and the regular incisors (difference 7.5% and 2.4%, respectively). The pulp area was greater in the talon teeth (37.4%). The latter had an effect on the increase in the mesio-distal and labio-palatal dimensions of the talon teeth (17.6% and 23.9%, respectively). The fact that the talon cusp has normal enamel and dentin layers with a substantial enlarged pulp tissue suggests that similar developmental anomalies occur during tooth morphodifferentiation as in taurodontism and dens evagintus of premolars.