Podcast
Questions and Answers
What is the primary composition of dentine?
What is the primary composition of dentine?
Which type of dentine is formed after the completion of the tooth root and continues throughout life?
Which type of dentine is formed after the completion of the tooth root and continues throughout life?
Which of the following best describes the function of dentine?
Which of the following best describes the function of dentine?
What is the approximate percentage of organic material in dentine?
What is the approximate percentage of organic material in dentine?
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Which type of dentine is often formed in response to injury or trauma?
Which type of dentine is often formed in response to injury or trauma?
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Which of the following tissues is NOT part of the oral and dental sciences?
Which of the following tissues is NOT part of the oral and dental sciences?
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Which functional characteristic of dentine is primarily attributed to its collagenous matrix?
Which functional characteristic of dentine is primarily attributed to its collagenous matrix?
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The presence of dental tubules in dentine is primarily associated with which of the following?
The presence of dental tubules in dentine is primarily associated with which of the following?
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What is a key function of dental tubules in dentine?
What is a key function of dental tubules in dentine?
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Which component makes up the largest proportion of the organic material in dentine?
Which component makes up the largest proportion of the organic material in dentine?
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What primarily leads to the formation of tertiary dentine?
What primarily leads to the formation of tertiary dentine?
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Which characteristic is NOT true regarding the composition of dentine?
Which characteristic is NOT true regarding the composition of dentine?
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How does the structure of dentine contribute to its function in the tooth?
How does the structure of dentine contribute to its function in the tooth?
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Which type of dentine is typically formed in response to external stimuli or damage?
Which type of dentine is typically formed in response to external stimuli or damage?
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What is the primary organic component of dentine's matrix?
What is the primary organic component of dentine's matrix?
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Which statement accurately describes the composition of dentine?
Which statement accurately describes the composition of dentine?
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What does dentinogenesis refer to?
What does dentinogenesis refer to?
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Which tissue supports the dentine and helps anchor the tooth within the jawbone?
Which tissue supports the dentine and helps anchor the tooth within the jawbone?
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Study Notes
Histology of Dentine
- Dentine is a hard, yellowish tissue that forms the bulk of a tooth.
- It's located between the enamel and the pulp.
- It has 3 types: primary, secondary, and tertiary.
Intended Learning Outcomes
- Students should be able to describe the composition and structure of dentine.
- They should be able to differentiate among the 3 types of dentine.
- They should be able to explain how the structure of dentine relates to its function.
- Students should be able to apply this knowledge to understand the clinical relevance of dentine in health and disease.
- This is based on GDC Learning Outcomes 1 1 5.
Tissues of Teeth and Supporting Structures
- Enamel
- Dentine
- Pulp
- Cementum
- Alveolar bone
- Periodontal ligament
- Gingiva
Refresh Prior Knowledge
- Students should know the location of dentine.
- Learners need to understand dentinogenesis (how dentine forms).
- They should recall the embryonic origin of dentine.
- Review previous lectures on oral embryology and tooth morphology for these topics.
Why Know About Dentine?
- Knowledge of dentine is crucial for clinical assessment, diagnosis, and management.
- It helps interpret dentine hypersensitivity, restorative materials, caries, affected and healthy dentine, and pathology and repair linked to pulp.
- Examples include using radiographs and interpreting the results.
Key Features: Dental Tubules - Composition and Structure
- Dentine is approximately 70% inorganic minerals (calcium hydroxyapatite), 20% organic material (primarily collagen), and 10% water.
- Dentine differs from enamel in its composition and quantity.
- The composition affects dentine's properties, like its resistance to fracture and ability to absorb shock.
Structural Features - Dentine Tubules 1-3
- Based on the minute tubules that permeate dentine, extending from the DEJ (dentinoenamel junction) to the pulp chamber.
- Peritubular/intratubular dentine surrounding the tubules is highly calcified, low in collagen.
- Intertubular dentine is between tubules, less calcified, containing more collagen.
Structural Features - Dentine Tubules 4
- Odontoblast process extends into the tubules.
- Periodontoblastic space surrounds the odontoblast process, containing fluid—understanding this is key to dentine hypersensitivity.
Structural Features - Interglobular Dentine
- Areas of unmineralized or hypomineralized dentine in the circumpulpal dentine.
- This is often found just beneath the mantle dentine.
- Occurrence may be linked to vitamin D deficiency or high fluoride exposure during dentinogenesis.
Structural Features - Sclerotic Dentine
- Dentine tubules can calcify via mineral deposition.
- Most prevalent apically in the root and midway in the crown - increases with age.
- Calcification reduces permeability and may be linked to protection from further damage.
Structural Features - Dead Tracts
- Empty dentine tubules where the odontoblastic process has retracted or died.
- Result of physiological or pathological processes, increasing with age.
Structural Features - Incremental Lines 1 and 2
- Incremental lines in dentine are similar to enamel lines, visible under a microscope.
- Lines of Von Ebner represent dentinogenesis increments.
- Contour lines of Owen are more distinct at the junction of primary and secondary dentine, delineated by changes in dentine tubule direction.
Structural Features - Granular Layer of Tomes
- A narrow dentine layer with granular appearance.
- Located in root dentine beneath the cemento-dentinal junction.
- More numerous towards the apex.
- A result of interference with dentine mineralisation by the dental sac.
Types of Dentine Overview
- Dentine is heterogeneous, with 3 main types based on formation location and timing.
- Mantle dentine forms first and outlines the dentine, adjacent to enamel and cementum.
- Circumpulpal dentine forms the bulk of the dentine.
- Contains dentine tubules, located between the mantle and pre-dentine.
- Pre-dentine is adjacent to the pulp chamber.
Primary Dentine
- The major part of dentine, formed before root completion.
- Composed of mantle and circumpulpal dentine.
Secondary Dentine
- Forms after root completion, slowly throughout life.
- Concentrated over the pulp roof and floor, reducing the pulp chamber size over time.
- Structurally similar to primary dentine, but less regular.
Tertiary Dentine
- Also called reactionary or reparative dentine.
- Forms in response to various stimuli (e.g., caries, attrition, abrasion) and is usually localized to the area where the stimuli occurs.
- Its structure varies according to the intensity and duration of the stimulus.
Clinical Significance of Tertiary Dentine
- Tertiary dentine formation is a response to various stimuli, like caries, abrasion, and attrition, affecting pulp shape.
- Clinical assessment includes identifying the type of stimuli and the impact on the pulp.
Reactionary vs Reparative Tertiary Dentine
- Reactionary: deposited by pre-existing odontoblasts.
- Reparative: deposited by newly differentiated odontoblast-like cells, forming part of the pulp.
Functions Linked to Dentine Structure
- Dentin functions for support, protection, communication, and repair of the tooth structure.
- Functions depend on its structure, like the dentin tubules housing fluid allowing communication with the pulp.
Dentine Colour
- In health, dentine is more yellowish, less mineralised, and absorbs more light than enamel.
- In disease, dentine colour changes to brown or other colours, influencing crown appearance to a greyish tone.
- The various colour changes are used clinically to detect disease and monitor treatment.
Dentine Permeability
- Dentine tubules and organic content make dentine permeable to varying degrees.
- Permeable regions are higher apically and closer to the pulp, related to disease progression.
- Understanding this is important, because caries and sensitivity are affected by permeability.
Dentine Communication
- Dentine tubules and odontoblast process facilitate communication with the pulp.
- This allows the transmission of sensations (e.g., temperature, pressure).
Fluid Content and Dentine Hypersensitivity
- Dentine fluid in tubules can influence sensitivity when exposed via irritation from pressure (e.g. biting).
- This impacts restorative procedures requiring minimal or no anaesthetics.
Radiographic Appearance of Dentine/Caries
- Dentine is radiopaque on radiographs.
- Diseased dentine, like caries, appears radiolucent compared to enamel and healthy dentine on X-Rays.
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Description
This quiz covers the histology of dentine, a crucial tissue in tooth anatomy. Students will explore its composition, structure, and the differences among primary, secondary, and tertiary dentine. Understanding the clinical significance of dentine in health and disease is also emphasized.
