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Questions and Answers
What occurs to the tooth surface when the pH decreases?
What occurs to the tooth surface when the pH decreases?
Which of the following best describes histopathology?
Which of the following best describes histopathology?
What are the consequences of prolonged demineralization of the tooth surface?
What are the consequences of prolonged demineralization of the tooth surface?
Which of the following statements about enamel caries is true?
Which of the following statements about enamel caries is true?
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What is one of the first visible signs of enamel caries?
What is one of the first visible signs of enamel caries?
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In the context of dental caries, what does the term 'zones of destruction' refer to?
In the context of dental caries, what does the term 'zones of destruction' refer to?
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What type of carbohydrate is predominantly linked to the progression of enamel caries?
What type of carbohydrate is predominantly linked to the progression of enamel caries?
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What is the relationship between tooth demineralization and pH levels?
What is the relationship between tooth demineralization and pH levels?
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Which factors are essential to prevent and manage dental caries effectively?
Which factors are essential to prevent and manage dental caries effectively?
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What does ICDAS stand for?
What does ICDAS stand for?
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What is the score assigned to a tooth that is clinically sound and shows no evidence of caries?
What is the score assigned to a tooth that is clinically sound and shows no evidence of caries?
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Which code is associated with initial stage caries that shows no evidence when the tooth surface is wet?
Which code is associated with initial stage caries that shows no evidence when the tooth surface is wet?
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What characterizes moderate stage caries in the ICDAS scoring system?
What characterizes moderate stage caries in the ICDAS scoring system?
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Which of the following signs indicates that a carious lesion is at initial stage?
Which of the following signs indicates that a carious lesion is at initial stage?
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Why was the ICDAS developed?
Why was the ICDAS developed?
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What feature does Code 2 of the ICDAS scoring represent?
What feature does Code 2 of the ICDAS scoring represent?
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Which score would apply if there are distinct visual changes in enamel, visible under both wet and dry conditions?
Which score would apply if there are distinct visual changes in enamel, visible under both wet and dry conditions?
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In the ICDAS scoring system, what does a score of 3 denote?
In the ICDAS scoring system, what does a score of 3 denote?
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What does the ICDAS scoring system primarily address?
What does the ICDAS scoring system primarily address?
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What initiates the carious process in enamel?
What initiates the carious process in enamel?
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Under what conditions does the tooth enamel dissolve further to cause microporosities?
Under what conditions does the tooth enamel dissolve further to cause microporosities?
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What clinical signs first manifest as enamel caries progress?
What clinical signs first manifest as enamel caries progress?
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Why do early white spots appear white on the enamel surface?
Why do early white spots appear white on the enamel surface?
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What is indicated if a white spot lesion incorporates exogenous pigmentation?
What is indicated if a white spot lesion incorporates exogenous pigmentation?
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Which method is necessary to identify all histological zones of established enamel caries?
Which method is necessary to identify all histological zones of established enamel caries?
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What characterizes pit and fissure caries compared to smooth surface caries?
What characterizes pit and fissure caries compared to smooth surface caries?
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Established enamel caries consists of how many distinct zones?
Established enamel caries consists of how many distinct zones?
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What occurs when enamel begins to lose mineral content due to acid exposure?
What occurs when enamel begins to lose mineral content due to acid exposure?
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What is a common misconception regarding the appearance of white spot lesions?
What is a common misconception regarding the appearance of white spot lesions?
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What is the primary characteristic of the Surface Zone in enamel caries?
What is the primary characteristic of the Surface Zone in enamel caries?
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Which zone in enamel caries typically has the largest pore volume?
Which zone in enamel caries typically has the largest pore volume?
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What causes the appearance of the Dark Zone under light microscopy?
What causes the appearance of the Dark Zone under light microscopy?
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How does the Translucent Zone differ from the other zones in terms of pore volume?
How does the Translucent Zone differ from the other zones in terms of pore volume?
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Why is the pore volume of the Surface Zone lower than that of deeper lesion areas?
Why is the pore volume of the Surface Zone lower than that of deeper lesion areas?
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What is the defining feature of the Body of the Lesion in terms of visibility?
What is the defining feature of the Body of the Lesion in terms of visibility?
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How is the size of porosities in enamel caries obtained?
How is the size of porosities in enamel caries obtained?
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Which zone is considered the initial area of destruction in the carious process?
Which zone is considered the initial area of destruction in the carious process?
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What role does lipid and protein presence play in the Dark Zone?
What role does lipid and protein presence play in the Dark Zone?
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Which is NOT a characteristic of the Body of the Lesion?
Which is NOT a characteristic of the Body of the Lesion?
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Study Notes
Histopathology of Enamel and Dentine Caries
- Topic: Histopathology of enamel and dentine caries
- Subject: Oral and Dental Science
- Presenter: Josh Hudson
GDC Learning Outcomes
- Describe oral diseases & their relevance to prevention, diagnosis, and treatment
- Explain the aetiology and pathogenesis of oral disease
- Describe appropriate dental, oral, craniofacial, and general anatomy, and explain their application to patient management
Pre-reading: Aetiology of Dental Caries
- Key factors for dental caries: Time, plaque bacteria, fermentable carbohydrates, susceptible tooth surface
Pre-reading: Histology of Enamel and Dentine Lectures
- Topic: Histological study of enamel and dentine
Histopathology of Enamel Caries
- Topic: Study of enamel caries
Learning Objectives
- Describe the clinical appearance of enamel caries
- Describe the histology of enamel caries
- Identify and name the 4 zones of destruction in enamel caries
- Describe the clinical appearance of enamel caries in relation to its histopathology
Recap on Caries Aetiology
- As pH lowers, the tooth surface (hydroxyapatite) demineralizes, breaking down into component ions
- If pH does not neutralize, demineralization leads to caries
- Chemical equation for demineralisation: Ca10(PO4)6(OH)2 → Ca2+, PO43− + OH− (hydroxyl ion)
How do we know this is happening clinically?
- Topic: Clinical methods to identify caries
ICDAS Score
- International caries detection and assessment system
- ICDAS was developed for clinical research, clinical practice, and epidemiological purposes.
- A clinical scoring system for diagnosing caries
- Allows detection of the caries process at every stage and characterisation of the carious activity of the lesion
- Developed due to inconsistencies in caries diagnosis
ICDAS Score - Score 0
- Sound tooth
- No evidence of caries when tooth surface is wet
- No evidence of caries when tooth surface is dry
- Tooth clinically sound
ICDAS Score - Code 1 (Initial Stage Caries)
- No evidence of caries when tooth surface is wet
- First visual signs (white spot and/or brown discolouration) after air drying
- Initial stage caries
ICDAS Score - Code 2 (Initial Stage Caries)
- Distinct visual changes in enamel
- Visible when wet and dry
ICDAS Score - Code 3 (Moderate Stage Caries)
- Localized enamel breakdown without visible dentine exposure
- Visible when wet and dry
- Prolonged drying reveals loss of enamel integrity
How does this apply to the histological appearance?
- Topic: Relation between clinical and histological view of caries
Enamel Caries Microscopic Appearance
- SEM (scanning electron microscope) images of enamel caries
Enamel Caries Microscopic Appearance
- Caries process starts with slight etching of enamel surface under dental plaque
- This is reversible and occurs frequently
- Healthy enamel beside etched enamel
- Microscopic view of enamel caries-induced microporosities
Enamel Caries Microscopic Appearance (Continued)
- Under cariogenic circumstances, tooth dissolving results in microporosities in enamel surface
- Typically located at prism boundaries
Enamel Caries Micro/macroscopic Appearance
- First clinical signs: white spots (greater proportion of incoming light is scattered compared to surrounding enamel)
- Elevated porosities due to mineral loss
- Air (or electrolyte) in porosities has different refractive index compared to sound enamel
Enamel Caries Micro/macroscopic Appearance
- White spot lesions can incorporate exogenous pigmentation, making them appear brown
- This may suggest a longer lesion duration, but does not guarantee it
Established Enamel Caries Histology
- Established enamel caries (still within enamel, not extending into dentine) has four distinct zones
- Surface zone (relatively unaffected, remineralization-able)
- Body of the lesion (largest demineralization area)
- Dark zone (cannot transmit light, some remineralization and demineralization occurs)
- Translucent zone (advancing edge of lesion, initial area of destruction)
Established Enamel Caries Histology (Continued)
- Description of each zone in relation to its characteristic(s): pore volume, visibility, and remineralization potential
- Wedge-shaped lesions of smooth surface caries and pit/fissure caries
Established Enamel Caries Histology (Continued)
- Samples need to be cleared using quinoline for identifying histological zones
- Differences based on amount and size of porosities are observed using transmitted light microscopy
- Varying clearing mediums of different optical refractive indices used for pore volume/size determination using transmitted/ polarized light microscopy
1. Surface Zone
- Outermost zone of the lesion
- Also called pseudo-intact surface or intact surface
- High mineral content
- Pore volume below 5%
- Remineralize ability due to its contact location with saliva or plaque
2. Body of the Lesion
- Area below the surface zone
- Visible in conventional radiographs
- Demonstrates porosities of varying size
- Pore volume from 5-25%
- Translucent with Retzius striae
3. Dark Zone
- Thin layer below the body of the lesion
- Called dark zone due to small porosities (clearing medium cannot enter)
- Dark appearance under light microscopy
- Pore volume 2-4%
- Possibly due to lipid and protein presence that hampers mineral precipitation
- Suggests remineralization
4. Translucent Zone
- Layer at the advancing edge of the lesion
- Initial area of destruction as part of the carious process
- Pore volume of 1% (sound enamel: 0.1%)
- Demineralization
- Initial dissolution along gaps between rods
Video for review
- This video summarises the process: https://www.youtube.com/watch?v=Y_o0ygwA6CI (from 4:40)
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Description
This quiz delves into the histopathology of enamel and dentine caries, covering the aetiology, clinical appearance, and histological structure. Test your knowledge on the zones of destruction and their significance in dental science. Ideal for students and professionals in Oral and Dental Science.
