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Odontogenesis & Tooth Eruption - Coggle Diagram
Odontogenesis & Tooth Eruption
Origin & Initiation (Week 6-7)
Definition: The process of tooth formation and eruption.
Time: Begins between the 6th and 7th week of prenatal development.
Main Process: Induction
Involves active interaction between Ectoderm (epithelial tissue) and Ectomesenchyme (derived from neural crest cells).
Originating Tissues & Derivatives:
Oral Epithelium/Ectoderm: Forms the epithelial component and forms enamel.
Ectomesenchyme (Neural Crest derived): Forms the mesenchymal component. Forms hard tissues (dentin, cementum) and supporting structures (pulp, PDL)
Embryological Origin of the Tooth Germ (The 3 Components)
Enamel Organ
Origin: Oral Epithelium (Ectoderm).
Derivative: Forms Enamel.
Function: Shapes the crown and induces dental papilla cells to become odontoblasts.
Dental Papilla
Origin: Neural crest-derived Ectomesenchyme.
Derivatives: Forms Dentin (via Odontoblasts) and the Dental Pulp.
Function: Plays a key role in tooth morphogenesis (determines crown shape/size).
Dental Follicle (Dental Sac
Origin: Ectomesenchyme surrounding the tooth germ.
Derivatives (The Periodontium):
Cementum (via Cementoblasts).
Periodontal Ligament (PDL) (via Fibroblasts).
Alveolar Bone (via Osteoblasts).
Stages of Tooth Germ Development (Timeline)
Initiation Stage
Timing: Week 6-7.
Structure: Dental Placode (thickening of epithelium).
Bud Stage
Timing: Week 8.
Process: Proliferation of dental lamina into ectomesenchyme.
Structure: Forms 10 tooth buds per arch.
Cap Stage
Timing: Week 9-10.
Process: Proliferation and differentiation.
Structure: The three components of the tooth germ become distinct.
Bell Stage
Timing: Week 11-12.
Process: Cell differentiation and Morphogenesis (crown shape determination).
Cell Differentiation: Inner Enamel Epithelium (IEE) cells differentiate into Pre-Ameloblasts, while dental papilla cells become Odontoblasts through mutual induction.
Hard Tissue Formation (Apposition & Maturation)
Dentinogenesis (Dentin Formation)
Timing: Begins during the Bell Stage.
Cell: Formed by Odontoblasts (from Dental Papilla).
Sequence: Odontoblasts form Dentin first.
Amelogenesis (Enamel Formation)
Cell: Formed by Ameloblasts (differentiated IEE cells).
Sequence: Ameloblasts form Enamel matrix on the dentin surface.
Sub-stages:
Presecretory: Ameloblasts differentiate and become polarized.
Secretory (Formative): Ameloblasts secrete enamel proteins. Tomes' process is key for forming enamel rods and interrods.
Maturation: Removal of water and organics, allowing inorganic substances to enter. Ameloblasts modulate between Ruffle-ended and Smooth-ended forms.
Root Formation & Supporting Tissues
Root Formation: Begins when the Cervical Loop develops into Hertwig’s Epithelial Root Sheath (HERS).
Supporting Structures (Periodontium)
Cementum: Formed by Cementoblasts; covers root dentin and anchors PDL fibers.
Periodontal Ligament (PDL): Formed by Fibroblasts; anchors tooth and provides sensory support.
Alveolar Bone: Formed by Osteoblasts; provides anchorage and is constantly remodeled.
Tooth Eruption Process
Definition: Tooth movement.
Stages of Tooth Movement:
Pre-eruptive tooth movement.
Eruptive tooth movement (Intraosseous and Supraosseous).
Post-eruptive tooth movement.