m Flashcards
What is the stomodeum?
The primitive oral cavity lined by stratified squamous epithelium called oral ectoderm.
What forms the buccopharyngeal membrane?
The contact between the stomodeum and the endoderm of the foregut.
When does the buccopharyngeal membrane rupture?
By the 27th day of gestation.
What role do neural crest cells play in tooth development?
They instruct the oral ectoderm to initiate tooth development.
What is the dental lamina?
A structure formed from the primary epithelial band that initiates deciduous tooth development.
At what week does the dental lamina begin to form?
At 6 weeks.
What are the components of the tooth germ?
- Enamel organ: Forms enamel. * Dental papilla: Forms dentin and pulp. * Dental follicle: Forms cementum, periodontal ligament, and alveolar bone.
When do permanent molars begin to develop?
- First molar: At 4 months in utero. * Second molar: At 1 year after birth. * Third molar: At 4–5 years.
What is the fate of the dental lamina after tooth bud formation?
It degenerates but may persist in regions like the third molar.
What is the vestibular lamina?
Develops labial/buccal to the dental lamina and hollows to form the oral vestibule.
What are the stages of enamel organ development?
- Bud Stage: Initiation of enamel organ. * Cap Stage: Enamel organ enlarges and forms a concavity. * Bell Stage: Enamel organ deepens, and tooth bud separates from oral epithelium.
What components make up the enamel organ?
- Outer Enamel Epithelium: Cuboidal cells. * Inner Enamel Epithelium: Tall columnar cells. * Stellate Reticulum: Star-shaped cells.
What is the role of the enamel knot?
Acts as a signaling center, producing growth factors.
What does the dental papilla develop into?
Dentin and pulp.
What is the dental sac?
Marginal condensation of ectomesenchyme around the enamel organ and papilla that develops into cementum, periodontal ligament, and alveolar bone.
What marks the beginning of mineralization and root formation?
Stage characteristics outlined by the boundary between the inner enamel epithelium and odontoblasts.
What initiates dentin formation?
Begins as a layer along the future dentinoenamel junction (DEJ) in the cuspal region.
What does Hertwig’s epithelial root sheath (HERS) dictate?
The shape, length, size, and number of roots.
What happens to HERS after dentin formation?
It disintegrates into epithelial remnants called cell rests of Malassez.
What is the significance of enamel pearls?
Formed if HERS cells differentiate into ameloblasts at root furcations.
Fill in the blank: The interaction between ectomesenchyme and _______ initiates tooth formation.
epithelium
What occurs during histodifferentiation?
Cells undergo morphological and functional changes, assuming specialized roles for dentin and enamel formation.
What is morphodifferentiation?
The establishment of the shape, size, and form of the tooth through differential growth.
What is involved in the apposition stage of tooth development?
Layer-by-layer deposition of extracellular matrix for enamel, dentin, and cementum.
True or False: Dentin formation occurs before enamel formation.
True
What is the significance of the basement membrane in tooth development?
Mediates interactions between epithelial and mesenchymal tissues.
