General Pathology Flashcards
What is a primary epithelial band?
It is a horse-shoe shaped thickening of epithelium. It is located at the future maxillary and mandibular arches. It gives rise to dental lamina and vestibular lamina.
What are the five histologically identifiable stages of tooth development?
- Bud stage
- Cap stage
- Bell stage
- Apposition
- Maturation
What occurs in bud stage?
Individual epithelial cells on the deep surface of dental lamina swell up and become visible. Hence why it is called a bud
What occurs in cap stage?
Proliferation of epithelial bud & invagination of the deeper surface of the epithelial bud forms the cap shape. Early histogenesis occurs.
What occurs during bell stage?
Shape has changed and epithelial component shape resembles the final occlusal shape. Enamel organ now has histologically distinct components.
What are 5 main cellular processes in early odontogenesis?
- Initiation
- Proliferation
- Differentiation
- Morphogenesis
- Maturation (all of these process may overlap)
When does initiation of odontogenesis occur?
Between 6 and 7 weeks in utero
What is an epithelial – mesenchymal interaction?
Tooth development involves interaction between epithelial and ectomesenchyme elements. This may involve chemical messengers, direct cell contact or effects of extracellular matrix.
What influences tooth shape during odontogenesis?
Dental papilla
What is the field model of tooth development?
It states that “Factors responsible for tooth development exist in the ectomesenchyme. Distinct overlapping fields for each type of tooth cells within each field express specific genes.”
What is the clone model of tooth development?
It states that: “clone of ectomesenchyme cells programmed early by epithelium to producer teeth of a given pattern”
What happens during the proliferation stage?
Controlled cell growth
What happens during the differentiation stage?
Cells become more specialised
What happens during morphogenesis?
Specific tissue structures develop.
What happens during the maturation stage?
Attainment of adult/final function and size. Complete mineralisation of dental hard tissue.