Dentine: Composition, Structure, and Function
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Questions and Answers

What approximate percentage of dentine's composition is made up of inorganic minerals?

  • 50%
  • 10%
  • 20%
  • 70% (correct)

Which structural component is the main structural unit of dentine?

  • Intertubular dentine
  • Dentine tubules (correct)
  • Interglobular dentine
  • Mantle dentine

What is the structure called that is immediately surrounding the odontoblastic process within the dentine tubule?

  • Peritubular dentine
  • Mantle dentine
  • Periodontoblastic space (correct)
  • Intertubular dentine

In which region of the tooth is the Granular Layer of Tomes located?

<p>Root (B)</p> Signup and view all the answers

Which type of dentine is formed before the completion of root formation?

<p>Primary dentine (A)</p> Signup and view all the answers

What is the primary characteristic of sclerotic dentine?

<p>Calcified tubules (D)</p> Signup and view all the answers

What is the clinical significance of the fluid-filled content within dentine tubules?

<p>Dentine hypersensitivity (D)</p> Signup and view all the answers

Which factor primarily influences the permeability of dentine?

<p>Tubule diameter (D)</p> Signup and view all the answers

How does the color of dentine typically change in disease compared to healthy dentine?

<p>Changes to brown (B)</p> Signup and view all the answers

What distinguishes reactionary dentine from reparative dentine in tertiary dentinogenesis?

<p>Cellular origin (C)</p> Signup and view all the answers

What is the composition of intertubular dentine compared to peritubular dentine?

<p>Less mineralized and more collagenous (C)</p> Signup and view all the answers

What is the functional significance of dentine's rigid yet elastic nature?

<p>Enables shock absorption (B)</p> Signup and view all the answers

How do the tubules run underneath the cusps?

<p>In an S-shape (B)</p> Signup and view all the answers

What is the space called that surrounds the odontoblastic process?

<p>The periodontoblastic space (C)</p> Signup and view all the answers

What are interglobular dentine?

<p>Areas of unmineralised dentine (B)</p> Signup and view all the answers

What vitamin deficiency can cause interglobular dentine?

<p>Vitamin D (A)</p> Signup and view all the answers

Why does the amount of sclerotic dentine increase with age?

<p>Due to tubule mineral deposition (C)</p> Signup and view all the answers

What is another name for tertiary dentine?

<p>Reactionary/reparative (C)</p> Signup and view all the answers

Where is the granular layer of Tomes found?

<p>In root dentine (B)</p> Signup and view all the answers

If tertiary dentine has tubules, what are they like?

<p>May be continuous or discontinuous (D)</p> Signup and view all the answers

What is the composition of dentine?

<p>70% inorganic, 20% organic, 10% water (D)</p> Signup and view all the answers

Name the correct order of the different layers of dentine.

<p>Mantle, circumpulpal, pre-dentine (D)</p> Signup and view all the answers

Which of the following features is unique to root dentine?

<p>Granular Layer of Tomes (D)</p> Signup and view all the answers

What is the function of dentine relating to the pulp?

<p>Support, protect, communicate with the pulp and repair (D)</p> Signup and view all the answers

What does it traditionally mean if the teeth appear more yellow clinically?

<p>Indicates good health (A)</p> Signup and view all the answers

What do the 'dead tracts' show about the odontoblastic processes?

<p>Odontoblastic processes have died/retracted (C)</p> Signup and view all the answers

How does dentine appear on radiographs?

<p>Radio-opaque (D)</p> Signup and view all the answers

What are the incremental lines called?

<p>Von Ebner lines (C)</p> Signup and view all the answers

Which is the most accurate statement about sclerotic dentine?

<p>Sclerotic dentine increases with age. (C)</p> Signup and view all the answers

Which type of dentine is usually localized to an area of stimulus?

<p>Tertiary dentine. (A)</p> Signup and view all the answers

What determines if caries will progress through dentine?

<p>How permaeable the dentine is (D)</p> Signup and view all the answers

Which of the following is approximately 20% of the composition of dentine?

<p>Organic Material (A)</p> Signup and view all the answers

Which of the following is also known as intratubular dentine?

<p>Peritubular dentine (D)</p> Signup and view all the answers

What is the name for the cytoplasmic extension of the odontoblast?

<p>Odontoblastic process (C)</p> Signup and view all the answers

What is the name for the more distinct incremental line at the interface between primary and secondary dentine?

<p>Contour Lines of Owen (A)</p> Signup and view all the answers

Which of the following best describes a visual characteristic of dentine?

<p>Yellow (B)</p> Signup and view all the answers

Once caries progresses to dentine, how can it be best described radiographically?

<p>Radiolucent (D)</p> Signup and view all the answers

What process allows sensations/feelings via the dentine?

<p>Communication (A)</p> Signup and view all the answers

What are some of the functions of dentine?

<p>Support, protect, communicate and repair. (A)</p> Signup and view all the answers

Which of the following best describes the arrangement of dentinal tubules near the dentinoenamel junction (DEJ) compared to near the pulp?

<p>More widely separated near the DEJ, more tightly packed near the pulp. (D)</p> Signup and view all the answers

What is the predominant inorganic component of dentine?

<p>Calcium hydroxyapatite (B)</p> Signup and view all the answers

What is the organic matrix of dentine mainly composed of?

<p>Collagenous proteins (A)</p> Signup and view all the answers

What is the approximate water content in dentine?

<p>10% (C)</p> Signup and view all the answers

What is the function of the periodontoblastic space?

<p>Contains fluid (C)</p> Signup and view all the answers

What is the function of the odontoblastic process?

<p>Cytoplasmic extension of odontoblast (B)</p> Signup and view all the answers

How might the arrangement of dentinal tubules contribute to dentine's sensitivity during a dental procedure?

<p>By facilitating fluid movement within the tubules, stimulating nerve endings in the pulp. (A)</p> Signup and view all the answers

Which statement accurately describes the mineral content of peritubular dentine compared to intertubular dentine?

<p>Peritubular dentine has a higher mineral content. (C)</p> Signup and view all the answers

What is the functional significance of dentinal tubules traversing in an S-shape through the dentine?

<p>Helping to withstand forces applied to the tooth. (D)</p> Signup and view all the answers

How does the collagen content in intertubular dentine compare to that in peritubular dentine?

<p>Intertubular dentine has more collagen. (B)</p> Signup and view all the answers

What characteristic makes dentine able to withstand occlusal forces?

<p>The S-shape of the tubules (C)</p> Signup and view all the answers

What happens to odontoblasts that become crowded during dentinogenesis?

<p>They may die off to make space. (C)</p> Signup and view all the answers

What is the clinical relevance of the communication between dentine and pulp?

<p>Mediating dentine hypersensitivity and protection (B)</p> Signup and view all the answers

From which embryonic structure is dentine derived?

<p>Ectomesenchyme (C)</p> Signup and view all the answers

If a patient experiences sharp pain from thermal stimuli, which component of the tooth is MOST directly responsible for transmitting this sensation?

<p>Dentine tubules and their fluid content (B)</p> Signup and view all the answers

Name the walls of the tubules.

<p>Peritubular/intratubular dentine (C)</p> Signup and view all the answers

What is found inside the dentine tubule?

<p>Odontoblastic process (B)</p> Signup and view all the answers

What is found between the tubules?

<p>Intertubular dentine (C)</p> Signup and view all the answers

Which of the following components is present in the dentinal tubules?

<p>Odontoblastic process (C)</p> Signup and view all the answers

What is the approximate percentage of organic material in dentine?

<p>20% (D)</p> Signup and view all the answers

Flashcards

Dentine Composition

Dentine is composed of approximately 70% inorganic minerals, 20% organic material, and 10% water.

Dentine Tubules

Minute tubules that permeate the dentine structure, extending from the DEJ to the pulp chamber.

Contents of Dentine Tubules

The odontoblastic process, a cytoplasmic extension of the odontoblast, is contained within dentine tubules.

Peritubular Dentine

Highly calcified wall of the dentine tubules with minimal collagen.

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Intertubular Dentine

Less calcified, more collagenous dentine between tubules, making up the bulk of dentine.

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Interglobular Dentine

Areas of unmineralized dentine that have failed to fuse, often found below mantle dentine.

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Sclerotic Dentine

Calcified dentine tubules via mineral deposition, common in apical third of root; reduces permeability.

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Dead Tracts

Empty dentine tubules where the odontoblastic process has died or retracted.

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Lines of Von Ebner

Incremental lines reflecting the pattern of dentinogenesis, close together and difficult to visualize.

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Contour Lines of Owen

More distinct incremental lines at the interface between primary and secondary dentine.

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Granular Layer of Tomes

Narrow layer found only in root dentine beneath the cemento-dentinal junction.

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Mantle Dentine

Initial formed dentine that outlines the periphery of the dentine adjacent to the enamel and cementum.

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Circumpulpal Dentine

The bulk of the dentine containing the dentine tubules, lying between the mantle and pre-dentine.

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Pre-dentine

Dentine matrix surrounding the pulp chamber.

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Primary Dentine

The bulk of the dentine within the tooth that forms prior to completion of root formation.

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Secondary Dentine

Dentine that forms slowly throughout life after root formation is complete.

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Clinical Significance of Secondary Dentine

Pattern of secondary dentine protects the dental pulp and helps it shrink over time.

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Tertiary Dentine

Tertiary dentine is usually localized to an area of the tooth in response to stimuli

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Main functions of dentine

Support for enamel, protection for pulp, communication via tubules, and repair through tertiary dentine.

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Dentine Structure Function

Dentine’s rigid mineral content and elastic collagen allow absorption of shock on teeth.

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Dentine color

Yellowish in health due to less mineralization, turning brown in disease.

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Dentine Permeability

Varies within the structure making it more / less permeable

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Dentine origin

Derived from ectomesenchyme neural crest

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Periodontoblastic space

Small fluid-filled space surrounding odontoblastic processes

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Communication in dentine

Located in dentine tubules and key for understanding dentine hypersensitivity

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Main structure of tubules

The dentine structure is permeated by tubules extending from the DEJ to the border of the pulp chamber

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Shape of tubules

Allows it to withstand forces

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Study Notes

Composition and Structure

  • Dentine is derived from ectomesenchyme.
  • It consists of 70% inorganic minerals, which are primarily calcium hydroxyapatite.
  • 20% of dentine is organic materials, consisting of 18% collagenous rich matrix and less than 2% non-collagenous matrix proteins and lipids.
  • Water makes up 10% of dentine.
  • Dentine gives the tooth is flexi, avascular, and mineralised qualities like connective tissue.

Dentine Tubules

  • Dentine tubules are the main structural component of dentine.
  • These tubules permeate the dentine structure, extending from the DEJ to the border of the pulp chamber.
  • The tubules follow an S-shape.
  • These withstand forces due to their shape.
  • Underneath cusps, incisal edges, and root tips, the tubules are almost straight.
  • Tubules are more widely separated near the DEJ compared to near the pulp, resulting in a tapered outline.
  • This pattern reflects the path of odontoblasts during dentinogenesis.
  • As odontoblasts become crowded, some may die off to create space.

Peritubular and Intertubular Dentine

  • The wall of the tubules is called peritubular or intratubular dentine.
  • It is highly calcified with minimal collagen.
  • Dentine between the tubules is intertubular dentine.
  • Intertubular dentine is less calcified, contains more collagen, and makes up the bulk of dentine.

Contents of the Dentine Tubule

  • Each tubule contains an odontoblastic process, which is a cytoplasmic extension of an odontoblast.
  • The odontoblastic process is surrounded by the periodontoblastic space, which is filled with fluid.
  • Communication from dentine to pulp is key for protection.
  • Dentine hypersensitivity can result due to this.

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Description

Explore the structure and function of dentine, a crucial dental tissue. Learn about its composition, including minerals, organic material, and water. Distinguish between primary, secondary, and tertiary dentine and understand the clinical significance of dentine in dental health and disease.

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