Ultrastructural analysis of enamel formation during in vitro development using chemically-defined medium.
To test the hypothesis that enamel biomineralization is regulated by sequential expression of an intrinsic genetic program, we designed experiments to determine if a serumless, chemically-defined medium is permissive for position-dependent ameloblast differentiation and subsequent enamel tissue-specific biomineralization in vitro. In the absence of serum or other exogenous growth factors, Swiss Webster strain mouse embryonic (15- and 16-days gestation) mandibular first molar tooth organs (cap stage) developed within 21 days in vitro into well-defined molar tooth organs expressing dentine and enamel biomineralization. Analysis of data obtained from von Kossa histochemistry for calcium salt formation, as well as ultrastructural information obtained from x-ray microanalysis, electron diffraction, transmission electron microscopy and scanning electron microscopy documented tissue-specific patterns of calcium hydroxyapatite formation in the absence of serum within organotypic cultures in vitro. An as yet unknown intrinsic genetic program regulates enamel formation in vitro.
Bringas
P
P
Department of Basic Sciences (Biochemistry), School of Dentistry, University of Southern California, Los Angeles 90089-0191.
Nakamura
M
M
Nakamura
E
E
Evans
J
J
Slavkin
H C
HC
D000818:Animals; D003743:Dental Enamel / Q000196:embryology* / Q000648:ultrastructure; D008334:Mandible; D051379:Mice; D008855:Microscopy, Electron, Scanning; D008963:Molar / Q000196:embryology* / Q000648:ultrastructure; D009805:Odontogenesis; D009924:Organ Culture Techniques