Dentin Development

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Questions and Answers

During which stage of tooth development does the enamel organ begin formation?

Cap stage

Crown formation stage

Bud stage

Dental lamina stage (correct)

What is the source of ameloblasts?

Dental lamina

Dental papilla

Dental sac

Enamel organ (correct)

Which cells determine the shape of the crown?

Enamel organ (correct)

Odontoblasts

Cementoblasts

Ameloblasts

What is the source of odontoblasts?

Dental papilla Signup and view all the answers

Which cells form the dentin and pulp of the tooth?

Odontoblasts Signup and view all the answers

What is the source of cementoblasts?

Dental sac Signup and view all the answers

What structure is formed by the dental sac?

Attachment apparatus Signup and view all the answers

What is the function of the dental papilla?

Forms the dentin and pulp of the tooth Signup and view all the answers

What is the function of the dental sac?

Forms the cementum, periodontal ligament, and alveolar bone Signup and view all the answers

What is the congenital absence of teeth usually a result of?

Interruption in bud stage Signup and view all the answers

During which stage of tooth development does the crown formation begin formation?

Bud stage Signup and view all the answers

What structures are formed by the dental papilla?

Dentin and pulp of the tooth Signup and view all the answers

Which cells determine the shape of the crown?

Enamel organ cells Signup and view all the answers

What is the source of odontoblasts?

Dental papilla Signup and view all the answers

What is the source of ameloblasts?

Enamel organ Signup and view all the answers

Which cells form the dentin and pulp of the tooth?

Odontoblasts Signup and view all the answers

Which layer of cells in the enamel organ is responsible for secreting glycosaminoglycans (GAGs)?

Stellate reticulum Signup and view all the answers

Which layer of cells in the enamel organ is essential for enamel formation and mineralization?

Stratum intermedium Signup and view all the answers

Which layer of cells in the enamel organ differentiate into ameloblasts, the enamel-forming cells?

Inner enamel epithelium (IEE) Signup and view all the answers

What is the junction between the outer enamel epithelium (OEE) and inner enamel epithelium (IEE) called?

Cervical loop Signup and view all the answers

What is the function of the outer enamel epithelium (OEE)?

Acting as a protective barrier Signup and view all the answers

What is the the outer enamel epithelium (OEE)associated with?

Capillary plexus Signup and view all the answers

Which cells induce the oral epithelium to form a horseshoe-shaped ridge along each jaw?

Ectomesenchyme cells Signup and view all the answers

What forms along each jaw as a result of ectomesenchyme induction of oral epithelium?

Dental lamina Signup and view all the answers

How many locations on each epithelial ridge does the ectomesenchyme induce tooth buds to form early enamel organs?

10 Signup and view all the answers

During which stage of tooth development does the initiation of proliferation of dental lamina epithelial cells into tooth buds occur?

Bud stage Signup and view all the answers

What does the ectomesenchyme do during the bud stage of tooth development?

It condenses around the epithelial bud Signup and view all the answers

During which stage of tooth development does the successional dental lamina form?

Cap stage Signup and view all the answers

What do the ectomesenchyme cells differentiate into during the cap stage of tooth development ?

Dental papilla and dental sac Signup and view all the answers

What becomes evident as the enamel organ begins formation during tooth development?

Shape of the tooth Signup and view all the answers

What are the four distinct layers that the enamel organs differentiate into during tooth development?

Outer enamel epithelium, inner enamel epithelium, stellate reticulum, stratum intermedium Signup and view all the answers

During which stage of tooth development does the morphodifferentiation occur?

Cap stage Signup and view all the answers

When and What is the process called when the epithelial cells in the enamel organ begin to differentiate into four distinct layers?

Cap stage Cytodifferentiation Signup and view all the answers

Which tissue is the enamel organ derived from?

Ectoderm Signup and view all the answers

What is the source of the dental sac?

Ectomesenchyme Signup and view all the answers

Where are the successional dental lamina derived from?

Ectoderm Signup and view all the answers

During which stage of tooth development is the enamel organ fully formed?

Bell stage Signup and view all the answers

What is determined during the bell stage of tooth development?

Location of the DEJ Signup and view all the answers

What is the space surrounding odontoblastic processes?

Dentinal tubule Signup and view all the answers

Which cells retreat from the dentinoenamel junction (DEJ) as enamel matrix is deposited?

Ameloblasts Signup and view all the answers

Which cells are located within the pulp of the tooth in mature dentin?

Odontoblasts Signup and view all the answers

What is the composition of dentin?

70% inorganic, 20% organic, 10% water Signup and view all the answers

Where are the odontoblasts located in the tooth?

Within the pulp Signup and view all the answers

What is the color of dentin?

Light yellow Signup and view all the answers

What is the hardness of mature dentin compared to enamel, cementum, and bone?

Less mineralized than enamel, more than cementum, and bone Signup and view all the answers

Which type of dentin forms rapidly in response to irritants such as attrition, abrasion, erosion, dental caries and trauma?

Tertiary dentin Signup and view all the answers

Which type of dentin is formed after the tooth is in occlusion and continues to form throughout the life of the tooth?

Secondary dentin Signup and view all the answers

Which type of dentin is formed prior to and during tooth eruption?

Primary dentin Signup and view all the answers

Which type of dentin forms along the entire pulp-dentin border?

Secondary dentin Signup and view all the answers

Which type of dentin is formed by preexisting or original odontoblasts?

Reactive dentin Signup and view all the answers

Which type of dentin is formed by newly differentiated odontoblasts?

Reparative dentin Signup and view all the answers

Which layer of dentin is the outer, first-formed layer of crown and root primary dentin, nearest to the DEJ/DCJ?

Mantle dentin Signup and view all the answers

Which layer of dentin is the remainder of primary dentin not apart of the first-formed layer, also referred to as any secondary or tertiary dentin?

Circumpulpal dentin Signup and view all the answers

What is the layer of newly secreted organic matrix (unmineralized) dentin?

Predentin Signup and view all the answers

Where are odontoblast processes found in mature dentin?

Found extending from odontoblast cell body into the dentinal tubule Signup and view all the answers

During tooth development, which cells differentiate into preoameloblasts?

IEE cells Signup and view all the answers

What is the first organic matrix secreted by odontoblasts in tooth development?

Predentin Signup and view all the answers

Which cells retreat from the Dentinoenamel junction (DEJ) after disintegration of basement membrane?

Odontoblasts Signup and view all the answers

During tooth development, what is the first organic matrix secreted by odontoblasts?

Predentin Signup and view all the answers

Which cells induce the differentiation of preameloblasts into ameloblasts?

Predentin Signup and view all the answers

Which cells induce the differentiation of DP cells into preodontoblasts?

Polarized preameloblasts Signup and view all the answers

During the apposition stage of tooth development, which cells differentiate into preodontoblasts?

Outer DP cells Signup and view all the answers

What is the first organic matrix secreted by odontoblasts during tooth development?

Predentin Signup and view all the answers

What happens to odontoblasts during the apposition stage of tooth development?

They retreat from the DEJ Signup and view all the answers

Which type of enamel is formed by early secretory ameloblasts?

Prismless enamel Signup and view all the answers

What are enamel prisms formed by?

Tomes' processes Signup and view all the answers

Which stage of ameloblasts is responsible for forming enamel prisms?

Late secretory Signup and view all the answers

Which cells are responsible for the formation of prismless enamel?

Ameloblasts Signup and view all the answers

What is located within tubules in the dentin?

Odontoblastic process Signup and view all the answers

Are there any cells present in normal dentin?

No, only odontoblastic processes Signup and view all the answers

True or false: Mature dentin is a non-vital tissue?

False Signup and view all the answers

True or false: Mature dentin can repair itself at the pulpal side?

True Signup and view all the answers

True or false: Mature dentin undergoes continued growth throughout the life of the tooth?

True Signup and view all the answers

Which structures extend from the DEJ to the dentin-predentin junction?

Dentinal tubules Signup and view all the answers

What is the approximate ratio of dentinal tubules that contain nerve fibers?

1 in 10 Signup and view all the answers

Where do dentinal tubules extend from and to within the dentin?

Dentinoenamel junction to the dentin-predentin junction Signup and view all the answers

True or false: Tertiary dentin forms on the pulp surface of the dentin in response to caries.

True Signup and view all the answers

True or false: Tertiary dentin is only deposited at sites where dentinal tubules are exposed.

True Signup and view all the answers

True or false: Tertiary dentin does not seal off tubules from the pulp.

False Signup and view all the answers

True or false: Tertiary dentin contains abundant and regular dentinal tubules?

False Signup and view all the answers

True or false: Reactive dentin have newly formed tubules continuous with those of primary dentin?

False Signup and view all the answers

True or false: Reparative dentin have preexisting dentinal tubules that are discontinuous?

True Signup and view all the answers

True or false: The size and orientation of collagen fibers in mantle dentin are different from those in circumpulpal dentin.

True Signup and view all the answers

True or false: Predentin is always present between odontoblasts and mineralized dentin.

True Signup and view all the answers

True or false: Circumpulpal dentin contains mainly Type III collagen.

False Signup and view all the answers

Which type of dentin is the most mineralized?

Peritubular dentin Signup and view all the answers

What is the main component of peritubular dentin?

Calcium Signup and view all the answers

Where is peritubular dentin found?

Lining the wall of the dentinal tubule Signup and view all the answers

Which type of dentin is the primary product of odontoblasts?

Intertubular dentin Signup and view all the answers

True or false: Intertubular dentin is more calcified than peritubular dentin.

False Signup and view all the answers

Which type of collagen fibers are found in intertubular dentin?

Type I collagen fibers Signup and view all the answers

Which type of dentin is located between dentinal tubules and makes up the majority of dentin?

Intertubular dentin Signup and view all the answers

Which area of the tooth is most commonly affected by sclerotic dentin?

Apical 1⁄3 of root Signup and view all the answers

True or false: Sclerotic dentin is an area of dentin where dentinal tubules are completely occluded with minerals.

True Signup and view all the answers

True or false: Sclerotic dentin increases with age.

True Signup and view all the answers

True or false: Spread of peritubular dentin is one of the possible mechanisms for the formation of sclerotic dentin.

True Signup and view all the answers

Which type of dentin is formed when odontoblasts are killed or injured and their processes retract, leaving empty dentinal tubules?

Dead tract dentin Signup and view all the answers

What is usually found in association with dead tract dentin?

Sclerotic dentin Signup and view all the answers

In which region of the tooth is dead tract dentin usually found?

Coronal dentin Signup and view all the answers

Dead tract dentin appears white in ground sections as only air is present

False Signup and view all the answers

Dead tract dentin is usually sealed off by secondary dentin

False Signup and view all the answers

Dead tract dentin contains empty dentinal tubules

True Signup and view all the answers

Which age-related change in dentin occurs?

Decreased volume of pulp Signup and view all the answers

What is the characteristic appearance of dead tract dentin?

Black in ground sections Signup and view all the answers

What is the term for the type of dentin formed when odontoblasts are killed or injured and their processes retract, leaving empty dentinal tubules?

Dead tract dentin Signup and view all the answers

Which type of tissue is the dental pulp derived from?

Dental papilla Signup and view all the answers

What are the functions of the dental pulp?

Formation, nutrition, defense, sensation, and reparative. Signup and view all the answers

When does the dental pulp form?

Throughout the life of the tooth Signup and view all the answers

Which part of the tooth communicates with the periodontal ligament?

Apical foramen Signup and view all the answers

What are accessory canals?

Connections between pulp canals and periodontal ligament Signup and view all the answers

What type of tissue is the dental pulp?

Soft tissue Signup and view all the answers

True or false: Coronal pulp is located in the pulp chamber and pulp horns?

True Signup and view all the answers

True or false: Radicular pulp is located in pulp canals?

True Signup and view all the answers

The odontoblastic layer is the outermost layer against predentin.

True Signup and view all the answers

Which zone of the pulp contains mainly fibroblasts?

Cell-rich zone Signup and view all the answers

Which zone of the pulp is located between the dentinal nerve fibers (odontoblastic layer) and the cell-rich zone?

Cell-free zone Signup and view all the answers

Which zone of the pulp is the central-most region?

Pulp core Signup and view all the answers

Which cells in the dental pulp are responsible for the formation and maintenance of pulp extracellular matrix?

Fibroblasts Signup and view all the answers

What is the function of undifferentiated mesenchymal cells in the dental pulp?

They differentiate into odontoblasts or other cells for repair Signup and view all the answers

Which cells in the dental pulp are involved with the elimination of dead cells?

Macrophages Signup and view all the answers

Which cells in the dental pulp capture and present foreign antigens to T-lymphocytes?

Dendritic cells Signup and view all the answers

What types of collagenous fibers are found in the pulp matrix?

Type I and III Signup and view all the answers

What is the main component of the ground substance in the pulp matrix?

Proteoglycans Signup and view all the answers

Which nerve bundles primarily innervate the dental pulp?

Sensory afferent nerves of the trigeminal nerve Signup and view all the answers

What types of axons are present in the nerve bundles entering the dental pulp?

Both myelinated and unmyelinated axons Signup and view all the answers

Where are dendritic cells located in the dental pulp?

Beneath the odontoblasts layer Signup and view all the answers

Which type of nerve fibers are associated with sharp localized pain when dentin is first exposed?

A-delta fibers Signup and view all the answers

What type of pain is associated with C fibers?

Dull and diffuse pain Signup and view all the answers

Which theory of dentin sensitivity suggests that fluid movement through tubules stimulates pulpal nerves?

Hydrodynamic theory Signup and view all the answers

What is the main function of sympathetic nerves in the dental pulp?

Regulates pressures within the pulpal tissues Signup and view all the answers

Approximately how many dentinal tubules contain a free nerve ending?

1 in 10 Signup and view all the answers

Which type of dentin is formed by newly differentiated odontoblasts?

Primary dentin Signup and view all the answers

Where are A-delta fibers located in the dental pulp?

Pulp-dentin border of the coronal portion Signup and view all the answers

What is the composition of dentin?

Hydroxyapatite crystals and organic matrix Signup and view all the answers

True or false: Sclerotic dentin increases with age.

True Signup and view all the answers

Which cells are responsible for the formation and maintenance of predentin and dentin?

Odontoblasts Signup and view all the answers

What is a role of odontoblasts in the dental pulp?

Repair damaged dentin Signup and view all the answers

What type of fibers are found in the core of the pulp and extend into the cell-free zone?

C fibers Signup and view all the answers

Where do postganglionic sympathetic branches from the superior cervical ganglion innervate in the dental pulp?

Pulpal blood vessels Signup and view all the answers

What types of lymphocytes are found in the pulp?

Both T-lymphocytes and B-lymphocytes Signup and view all the answers

Which type of lymphocytes are more abundant in the pulp?

T-lymphocytes Signup and view all the answers

True or false: Nerves in dentin are found in every dentinal tubule?

False Signup and view all the answers

True or false: The hydrodynamic theory is the most widely accepted theory for dentin sensitivity?

True Signup and view all the answers

Which theory of dentin sensitivity proposes that nerves synapse on odontoblast cell body

Theory of odontoblast as receptor Signup and view all the answers

What is the role of odontoblasts in dentin sensitivity according to the text?

Odontoblasts act as receptors Signup and view all the answers

Which theory of dentin sensitivity is considered the most plausible?

Hydrodynamic theory Signup and view all the answers

Study Notes

Stages of Tooth Development and the Role of Dental Tissues

Dental lamina induces the formation of tooth buds and early enamel organs.
Each jaw has ten locations where tooth buds are induced by ectomesenchyme cells.
Primary teeth form from the successional dental lamina, while permanent molars have their own dental lamina.
The bud stage is characterized by the development of the enamel organ and the initiation of tooth buds.
Interruption in the bud stage can result in congenital absence of teeth.
The cap stage involves the morphodifferentiation and cytodifferentiation of the enamel organ.
Ectomesenchyme cells condense around the developing cap, forming the dental papilla and dental sac.
The enamel organ is derived from oral epithelium and is responsible for shaping the crown and inducing dentin formation.
The dental papilla, derived from ectomesenchyme, forms the dentin and pulp of the tooth and determines the type of tooth.
The dental sac, also derived from ectomesenchyme, forms the cementum, periodontal ligament, and alveolar bone.
The outer enamel epithelium provides protection and is associated with the capillary plexus.
The inner enamel epithelium differentiates into ameloblasts, initiates dentin formation, and forms the enamel knot.

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Description

Test your knowledge on dental development with this quiz! Learn about the key stages and processes involved in the formation of teeth, including the induction of tooth buds, enamel organ development, and the role of dental lamina. Discover fascinating facts about primary and permanent teeth formation.