D514 Lecture 8: Dentin & Pulp Questions with
Complete Solutions
What are dentin and pulp sometimes referred to as?
dentin-pulp complex as they are closely related
What are dentin and pulp products of?
Dental Papilla- neural crest derived ectomesenchymal cells
What type of tissue is dentin?
hard connective tissue
What type of tissue is pulp?
soft connective tissue
Why do both dentin and pulp belong to connective tissue?
Both dentin and pulp belong to connective tissue because they originate from
ectomesenchymal cells.
What does dentin form in the tooth?
forms the bulk of the tooth crown and root
What does dentin provide a protective covering for?
pulp and support for enamel
How does dentin's resilience benefit the tooth?
Dentin’s resilience provides flexibility, which helps prevent fracture of the overlying
brittle enamel.
How does dentin affect the color of the tooth crown?
,Light passes through the translucent enamel and reflects the underlying yellowish
dentin, influencing the color of the crown.
Compare dentin to bone and enamel.
dentin is slightly harder than bone but softer than enamel
Does dentin have blood vessels?
No, it is avascular.
Why is dentin considered a vital tissue, unlike enamel?
-It contains odontoblast processes. These odontoblasts remain at the dentin-pulp
boundary, allowing for limited repair by laying down new dentin in response to
physiological stimuli or caries, even after tooth eruption.
-In contrast, enamel is NOT a vital tissue; once laid down by ameloblasts, no further
repair occurs as the ameloblasts do not remain in the enamel structure.
What percent of mature dentin is inorganic vs organic?
-70% inorganic - mineralized components
-20% organic (protein) components
-10% water
What is the inorganic component of dentin?
calcium phosphate in the form of hydroxyapatite
What are the organic components of dentin?
-collagen - 90% of the protein - mainly type 1 with small amounts of types III and IV
-dentinsialoprotein, dentinphsphoprotein, dentinglycoprotein
What type of collagen is found in dentin?
, -mostly type 1 and small amounts of type III and IV
-collagen is very resilient because its a fiber thus gives dentin its resilience
other proteins found in dentin besides collagen and their role
- dentisialoprotein, dentinphosphoprotein, and dentinglycoprotein
-more important in the formation of the dentin during development
When does dentinogenesis begin?
when the tooth germ has reached bell stage of odontogenesis
What forms dentin during the bell stage?
-formed by odontoblasts that differentiate from the ectomesenchymal cells of dental
papilla
-layer closest to enamel will differentiate into odontoblasts
What becomes pulp of the tooth once dentin formation begins?
ectomesenchymal cells
Where does dentin formation begin?
adjacent to the concave tip of the folded inner enamel epithelium (IEE) - at the future
cusp site
How does dentinogenesis progress in the crown of the tooth?
Dentin formation continues down the cusp slope until it reaches the cervical loop,
forming the coronal dentin.
When does root dentin formation begin?
Root dentin forms once the Hertwig's Epithelial Root
Sheath (HERS) initiates the differentiation of root odontoblasts.
Complete Solutions
What are dentin and pulp sometimes referred to as?
dentin-pulp complex as they are closely related
What are dentin and pulp products of?
Dental Papilla- neural crest derived ectomesenchymal cells
What type of tissue is dentin?
hard connective tissue
What type of tissue is pulp?
soft connective tissue
Why do both dentin and pulp belong to connective tissue?
Both dentin and pulp belong to connective tissue because they originate from
ectomesenchymal cells.
What does dentin form in the tooth?
forms the bulk of the tooth crown and root
What does dentin provide a protective covering for?
pulp and support for enamel
How does dentin's resilience benefit the tooth?
Dentin’s resilience provides flexibility, which helps prevent fracture of the overlying
brittle enamel.
How does dentin affect the color of the tooth crown?
,Light passes through the translucent enamel and reflects the underlying yellowish
dentin, influencing the color of the crown.
Compare dentin to bone and enamel.
dentin is slightly harder than bone but softer than enamel
Does dentin have blood vessels?
No, it is avascular.
Why is dentin considered a vital tissue, unlike enamel?
-It contains odontoblast processes. These odontoblasts remain at the dentin-pulp
boundary, allowing for limited repair by laying down new dentin in response to
physiological stimuli or caries, even after tooth eruption.
-In contrast, enamel is NOT a vital tissue; once laid down by ameloblasts, no further
repair occurs as the ameloblasts do not remain in the enamel structure.
What percent of mature dentin is inorganic vs organic?
-70% inorganic - mineralized components
-20% organic (protein) components
-10% water
What is the inorganic component of dentin?
calcium phosphate in the form of hydroxyapatite
What are the organic components of dentin?
-collagen - 90% of the protein - mainly type 1 with small amounts of types III and IV
-dentinsialoprotein, dentinphsphoprotein, dentinglycoprotein
What type of collagen is found in dentin?
, -mostly type 1 and small amounts of type III and IV
-collagen is very resilient because its a fiber thus gives dentin its resilience
other proteins found in dentin besides collagen and their role
- dentisialoprotein, dentinphosphoprotein, and dentinglycoprotein
-more important in the formation of the dentin during development
When does dentinogenesis begin?
when the tooth germ has reached bell stage of odontogenesis
What forms dentin during the bell stage?
-formed by odontoblasts that differentiate from the ectomesenchymal cells of dental
papilla
-layer closest to enamel will differentiate into odontoblasts
What becomes pulp of the tooth once dentin formation begins?
ectomesenchymal cells
Where does dentin formation begin?
adjacent to the concave tip of the folded inner enamel epithelium (IEE) - at the future
cusp site
How does dentinogenesis progress in the crown of the tooth?
Dentin formation continues down the cusp slope until it reaches the cervical loop,
forming the coronal dentin.
When does root dentin formation begin?
Root dentin forms once the Hertwig's Epithelial Root
Sheath (HERS) initiates the differentiation of root odontoblasts.
