WEEK 6 - DENTINE + PULP Flashcards
what is dentine?
the mineralised tissue that forms the bulk of the tooth
What happens to dentine throughout life?
it increases in thickness at the expense of the pulp
what commences dentinogenesis
the formation of predentine by odontoblasts
what does dentine consist of?
a large number of small parallel tubules in a collagen matrix
what colour is dentine?
pale yellow
Is dentine permeable?
yes
What is the chemical composition of dentin?
70% inorganic, 20% organic, 10% water
What is the inorganic component?
calcium crystals that give it its hardness
what is the organic component of dentin?
collagen and ground substance
What is the life cycle of odontoblasts?
preodontoblasts, secretory odontoblasts, resting odontoblasts
What are the features of preodontoblasts?
small ovoid cells, high nucleus to cytoplasmic ratio
What are the features of secretory odontoblasts?
large plump cell, open face nucleus
What are the features of resting odontoblasts?
thin, quiescent state
What are the 2 steps of dentinogenesis?
matrix formation and maturation
what is matrix formation?
after the differentiation of odontoblasts, it secretes predentin
what is the initial organic matrix (predentin) composed of?
small collagen fibrils and characteristic ground substance
What is the maturation or mineralization of dentin?
the formation of calcium hydroxyapatite crystals in the form of globules in the predentin
What are the two patterns of dentin mineralization that can be observed?
globular and linear calcification
where is primary dentin located and what are its histological features?
it is formed before completion of apical foramen and more rapidly and mineralized than secondary dentin
what is secondary dentin?
formed after completion of apical foramen, more slowly and less mineralized than primary. change of curvature