Histopathology of Enamel and Dentine Caries
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Questions and Answers

What occurs to the tooth surface when the pH decreases?

  • It demineralizes into component ions. (correct)
  • It becomes more mineralized.
  • It strengthens due to calcium absorption.
  • It remains unchanged.

    • Which of the following best describes histopathology?

  • The analysis of dental treatment outcomes.
  • The study of the structure and function of the tooth.
  • The examination of tissue samples to diagnose diseases. (correct)
  • The study of plaque bacteria exclusively.

    • What are the consequences of prolonged demineralization of the tooth surface?

  • It results in the formation of dental caries. (correct)
  • It prevents plaque accumulation.
  • It enhances enamel strength.
  • It repairs tooth decay naturally.

    • Which of the following statements about enamel caries is true?

    <p>Enamel caries can lead to breakdown of the tooth structure.</p> Signup and view all the answers

    What is one of the first visible signs of enamel caries?

    <p>White spots on the enamel surface.</p> Signup and view all the answers

    In the context of dental caries, what does the term 'zones of destruction' refer to?

    <p>The stages of caries development within enamel.</p> Signup and view all the answers

    What type of carbohydrate is predominantly linked to the progression of enamel caries?

    <p>Fermentable carbohydrates.</p> Signup and view all the answers

    What is the relationship between tooth demineralization and pH levels?

    <p>Lower pH levels result in demineralization of the tooth surface.</p> Signup and view all the answers

    Which factors are essential to prevent and manage dental caries effectively?

    <p>Regular brushing and oral hygiene practices.</p> Signup and view all the answers

    What does ICDAS stand for?

    <p>International Caries Detection and Assessment System</p> Signup and view all the answers

    What is the score assigned to a tooth that is clinically sound and shows no evidence of caries?

    <p>Score 0</p> Signup and view all the answers

    Which code is associated with initial stage caries that shows no evidence when the tooth surface is wet?

    <p>Code 1</p> Signup and view all the answers

    What characterizes moderate stage caries in the ICDAS scoring system?

    <p>Localised enamel breakdown without dentine exposure</p> Signup and view all the answers

    Which of the following signs indicates that a carious lesion is at initial stage?

    <p>White spot and/or brown discoloration after drying</p> Signup and view all the answers

    Why was the ICDAS developed?

    <p>To standardize caries diagnosis and assessment</p> Signup and view all the answers

    What feature does Code 2 of the ICDAS scoring represent?

    <p>Distinct visual changes under certain conditions</p> Signup and view all the answers

    Which score would apply if there are distinct visual changes in enamel, visible under both wet and dry conditions?

    <p>Score 2</p> Signup and view all the answers

    In the ICDAS scoring system, what does a score of 3 denote?

    <p>Localized enamel breakdown without dentin exposure</p> Signup and view all the answers

    What does the ICDAS scoring system primarily address?

    <p>Assessment of the caries process at all stages</p> Signup and view all the answers

    What initiates the carious process in enamel?

    <p>Slight etching of the enamel surface</p> Signup and view all the answers

    Under what conditions does the tooth enamel dissolve further to cause microporosities?

    <p>Under cariogenic circumstances</p> Signup and view all the answers

    What clinical signs first manifest as enamel caries progress?

    <p>White spots on the enamel</p> Signup and view all the answers

    Why do early white spots appear white on the enamel surface?

    <p>Due to a greater proportion of scattered incoming light</p> Signup and view all the answers

    What is indicated if a white spot lesion incorporates exogenous pigmentation?

    <p>The lesion has been present for a longer duration</p> Signup and view all the answers

    Which method is necessary to identify all histological zones of established enamel caries?

    <p>Using a clearing agent such as quinoline</p> Signup and view all the answers

    What characterizes pit and fissure caries compared to smooth surface caries?

    <p>They have a smaller opening but larger base</p> Signup and view all the answers

    Established enamel caries consists of how many distinct zones?

    <p>Four</p> Signup and view all the answers

    What occurs when enamel begins to lose mineral content due to acid exposure?

    <p>The enamel develops microporosities</p> Signup and view all the answers

    What is a common misconception regarding the appearance of white spot lesions?

    <p>They always suggest long-term presence</p> Signup and view all the answers

    What is the primary characteristic of the Surface Zone in enamel caries?

    <p>It is the outermost zone with high mineral content.</p> Signup and view all the answers

    Which zone in enamel caries typically has the largest pore volume?

    <p>Body of the Lesion</p> Signup and view all the answers

    What causes the appearance of the Dark Zone under light microscopy?

    <p>The clearing medium cannot enter small porosities.</p> Signup and view all the answers

    How does the Translucent Zone differ from the other zones in terms of pore volume?

    <p>It has a pore volume of 1%, which is the lowest.</p> Signup and view all the answers

    Why is the pore volume of the Surface Zone lower than that of deeper lesion areas?

    <p>It often comes into contact with mineral ions from saliva.</p> Signup and view all the answers

    What is the defining feature of the Body of the Lesion in terms of visibility?

    <p>It is visible and comprises the majority of the lesion.</p> Signup and view all the answers

    How is the size of porosities in enamel caries obtained?

    <p>Using transmitted light microscopy with varying clearing mediums.</p> Signup and view all the answers

    Which zone is considered the initial area of destruction in the carious process?

    <p>Translucent Zone</p> Signup and view all the answers

    What role does lipid and protein presence play in the Dark Zone?

    <p>They may hinder the mineral precipitation.</p> Signup and view all the answers

    Which is NOT a characteristic of the Body of the Lesion?

    <p>It appears completely mineralized.</p> Signup and view all the answers

    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

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    Histopathology of Enamel Caries PDF

    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.

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