Tooth formation is highly regulated at the molecular level
• terminal differentiation of specific cell types
• epithelial-mesenchymal interactions
• secretion of specific extracellular matrices
• controlled processing of those matrices
• regulation of ion deposition
• mineralization of the dental tissues
Tooth Formation is dependent on
Genetic Factors
Hundreds to several thousand genes likely involved (polygenic)
Tooth development is represented by four stages: bell stage (A), initial protein-matrix secretion (B), regression of dental epithelium (D), and tooth eruption (E). Sagittal sections were stained with alcian blue, hematoxylin, and eosin. Arrowheads, dental epithelium. Asterisks, artificial gaps. (Scale bars: 10 μm.) ISH analysis revealed the expression of SCPP1 (G),SCPP2 (H), SCPP3A (I), SCPP3B (J), SCPP4 (K), SCPP5 (L), COL1 (M), and SPARC(N) in various developmental stages. The expression of SCPP genes is summarized for the initial secretory stage (C) and for the eruption stage (F). IDE, inner dental epithelium; IPE, inner pharyngeal epithelium; Ms, mesenchyme expressing COL1 and SPARC; Od, odontoblasts; ODE, outer dental epithelium; OPE, outer pharyngeal epithelium; PRM, protein matrix.
Environmental Factors
Nutrition
Physical phenomenon
Infection
Molecular Determinants of Tooth Formation
• Over 10,000 genes involved in making a tooth
• Most genes involved in odontogenesis are expressed in non-dental tissues
• Some genes are relatively specific for development of the dental tissues (e.g. amelogenin gene)
Environmental Influences of Environmental Influences of Amelogenesis
• Nutrition
Major and minor components
• Calcium, phosphorus, protein, fluoride etc…
• Hypoxia
• Hyperthermia
• Infection
Congenital rubella, syphillus, CMV, etc…
• Physical Determinants
Space
Trauma
Interactions Leading to Developmental Dental Defects
Stages Required for Tooth Formation
• Initiation
• Histodifferentiation
• Morphodifferentiation
• Apposition
Secretory Phase
Transition Phase
Maturation Phase
• Stages are not discrete for any given tooth.
• Teeth develop over years beginning with the coronal portion of the crown.
• Can be mineralizing at the cusp tips while cervically cells are differentiating.
Tooth Development Video Explanation using Diagrams
Histology Of Tooth Development Video
