Supernumerary Tooth Formation in Mouse Molar Transplants

Abstract

The dentition of mice and rats, which normally consists of one incisor and three molars per quadrant, is not generally known for the occurrence of an excess number of teeth. This report describes experimentally induced supernumerary teeth which were observed in 5 of 44 mouse molar explants.Second molar tooth germs and the adjacent third molar rudiment were dissected as one explant from the mandibles of 18-day C57BL/10 mouse embryos. Care was taken to exclude incisor tissue The explants were cultured for 2 days on agar-solidified Eagle's basal medium** supplemented with 12 % fetal calf serum,** 1I% glutamine,** and 1% Gentamicint in a humid atmosphere of 5 % CO2 in air at 37 C in order to facilitate the subsequent placement of the explants in the anterior chamber of the eyes of homologous adult hosts. After two weeks, the eyes containing the transplants were then enucleated, processed through routine histological procedures, sectioned at 10 um, and stained with hematoxylin and Biebrich's scarlet.In all 44 intraocular grafts studied, the second molar tooth germs had advanced in development as evidenced by the presence of both enamel and dentin matrix. After 2 weeks of culture as arn intraocular graft, the third molar tooth germs had attained a stage of morphodifferentiation comparable to that acquired by the same tooth in vivo after 10 to 12 days of postnatal growth (COHN, Am J Anat 101: 295, 1957) indicating that the controlling influences governing third molar development had not been disturbed. Odontoblasts and a predentin matrix were aligned opposite a single layer of differentiated columnar ameloblasts with polarized nuclei. But, overall, these teeth were smaller in size when compared to the second molars. In five cases (11 %), a supernumerary tooth had developed adjacent to the lateral aspect of the third molar. The figure illustrates an intraocular graft with a normal appearing second and third molar plus an additional tooth which was similar

A novel mutation of adenomatous polyposis coli (APC) gene results in the formation of supernumerary teeth

“…Jae‐Young Kim found that APCDD1 modulates the gene expression of Wnt‐ and EK‐related signalling molecules at the cap stage of tooth development and is involved in tooth cusp patterning by modulating the epithelial rearrangement . Supernumerary tooth formation in mouse molar transplants . During the development of mouse tooth germ, we found that APC expression levels gradually declined at the embryonic phase (E13.5, E14.5, E16.5 and E18.5).…”

Aparición tardía de premolares supernumerarios. Revisión de literatura y presentación de casos

“…En otras anomalías como la disostosis cleidocraneal se ha reportado presencia de múltiples supernumerarios en 35% de los casos; y en pacientes con síndrome de Gardner en 21% de los afectados. (1,2,8,18,19) En unos pocos casos de pacientes con periodontitis juvenil localizada se ha informado la presencia de múltiples dientes supernumerarios y se ha sugerido la asociación entre estos desordenes (15) Estudios histológicos en ratas han demostrado que epitelio proliferativo remanente en áreas interseptales de la vaina radicular epitelial de Hertwig puede transformarse en células diferenciadas con posterioridad a trauma la cual da lugar a dientes supernumerarios (21) La presencia de dientes supernumerarios puede acarrear diversas irregularidades especialmente en la dentición mixta; en algunos casos pueden impedir la erupción de dientes permanentes o favorecer una erupción ectópica; en otros casos pueden desarrollar quistes; en cualquier caso una evaluación detallada clínica y radiológica debe preceder la conducta que se deba seguir (4,5)…”