Dental Caries and Carbohydrates Quiz
50 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which type of carbohydrates is considered the most cariogenic?

  • Disaccharides (correct)
  • Oligosaccharides
  • Polysaccharides
  • Monosaccharides

    • What role do lactobacilli play in dental caries?

  • They progress dental caries. (correct)
  • They prevent dental caries.
  • They do not play a role in dental caries.
  • They initiate dental caries.

    • Which of the following factors makes sucrose particularly cariogenic?

  • It diffuses slowly into dental plaque.
  • It is broken down rapidly by bacterial enzymes. (correct)
  • It is a polysaccharide.
  • It is expensive and hard to find.

    • What is the primary component produced by cariogenic bacteria during the breakdown of sucrose?

    <p>Dextran and Levan</p> Signup and view all the answers

    Why are polysaccharides less cariogenic compared to disaccharides?

    <p>They are not easily metabolized by oral bacteria.</p> Signup and view all the answers

    Which bacterium is primarily associated with the production of dental plaque due to sucrose metabolism?

    <p>Streptococcus mutans</p> Signup and view all the answers

    What happens during the hydrolysis of sucrose?

    <p>It results in the formation of glucose and fructose.</p> Signup and view all the answers

    Which of the following statements about the cariogenicity of carbohydrates is true?

    <p>Disaccharides are more cariogenic than monosaccharides.</p> Signup and view all the answers

    How does an increase in the amount of carbohydrate intake affect caries activity?

    <p>It increases caries activity.</p> Signup and view all the answers

    Which factor contributes most to increased caries susceptibility from carbohydrate intake?

    <p>Duration of the oral acid exposure.</p> Signup and view all the answers

    What characteristic of sticky carbohydrates contributes to their cariogenicity?

    <p>They remain in the mouth longer, allowing more acid production.</p> Signup and view all the answers

    What is true about refined carbohydrates concerning their effect on dental health?

    <p>They increase adhesiveness and cariogenic potential.</p> Signup and view all the answers

    Which carbohydrate is considered non-cariogenic despite being refined?

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

    In the Vipeholm Experiment, what was one significant finding regarding sticky carbohydrates?

    <p>Toffees and caramels exhibited the highest caries activity.</p> Signup and view all the answers

    What happens to the pH level in the mouth after consuming carbohydrates?

    <p>It gradually decreases and takes time to return to normal.</p> Signup and view all the answers

    Which of the following is NOT a reason why frequent carbohydrate intake increases caries risk?

    <p>Immediate normalization of mouth pH.</p> Signup and view all the answers

    What happens when demineralization periods exceed remineralization periods?

    <p>Caries is produced.</p> Signup and view all the answers

    Which type of tooth morphology is more susceptible to caries?

    <p>Deep and narrow pits</p> Signup and view all the answers

    Which of the following factors is least significant in the initiation of caries?

    <p>Genetic tooth morphology</p> Signup and view all the answers

    What is the role of fluoride in dental health?

    <p>It enhances remineralization and inhibits bacterial growth.</p> Signup and view all the answers

    Which condition makes newly erupted teeth more susceptible to caries?

    <p>Incomplete mineralization</p> Signup and view all the answers

    What type of fissures are generally more caries resistant?

    <p>U type fissures</p> Signup and view all the answers

    How can fluoride aid in increasing enamel resistance to acids?

    <p>By replacing hydroxyl groups in hydroxyapatite.</p> Signup and view all the answers

    Which of the following is an environmental factor affecting caries development?

    <p>Dental hygiene practices</p> Signup and view all the answers

    What characteristic of the early enamel lesion is described by its cone shape?

    <p>Base on the enamel surface</p> Signup and view all the answers

    Which zone of the early smooth surface enamel caries represents initial demineralization?

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

    What do submicroscopic pores in the enamel account for, in terms of total enamel volume?

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

    What causes the dark appearance of the dark zone when viewed by transmitted light?

    <p>Small pores allowing air to pass and scatter light</p> Signup and view all the answers

    Which method is used to determine the percentage of enamel pores by volume?

    <p>Polarized light microscope</p> Signup and view all the answers

    What is the consequence of the structural features being lost in the translucent zone?

    <p>Limited visibility under the microscope</p> Signup and view all the answers

    In microradiography, how are differences in the amount and distribution of minerals reflected?

    <p>By black and white representation</p> Signup and view all the answers

    What is believed to cause the smaller pores in the dark zone?

    <p>Remineralization during non-acid periods</p> Signup and view all the answers

    What distinguishes infected dentinal lesions from uninfected dentinal lesions?

    <p>Infected lesions are not remineralizable</p> Signup and view all the answers

    Which zone is not associated with uninfected dentinal lesions?

    <p>Zone of Liquefaction</p> Signup and view all the answers

    What is the primary cause of root surface caries?

    <p>Exposure of the tooth neck due to gingival recession</p> Signup and view all the answers

    Which reactionary change in dentin occurs due to severe stimuli?

    <p>Dead tract</p> Signup and view all the answers

    What characterizes tubular sclerosis in dentin?

    <p>Reduction in the size of dentinal tubules</p> Signup and view all the answers

    What is a characteristic feature of regular reactionary dentin?

    <p>Tubular structure at the dentin-pulp interface</p> Signup and view all the answers

    Which of the following zones is primarily associated with affected dentinal lesions?

    <p>Zone of Fatty Degeneration</p> Signup and view all the answers

    Which statement accurately describes bacteria's role in root surface caries?

    <p>Bacteria invade the superficial layer of demineralized cementum</p> Signup and view all the answers

    What occurs during the phase of bacterial invasion in enamel caries?

    <p>Minerals are removed allowing bacteria to invade.</p> Signup and view all the answers

    What is the primary result of the destruction phase in enamel caries?

    <p>Loss of structural integrity of enamel.</p> Signup and view all the answers

    What happens to enamel when acids reach the dentino-enamel junction (DEJ)?

    <p>Lateral spread of acids weakens enamel.</p> Signup and view all the answers

    What characterizes an uninfected dentinal lesion during early caries development?

    <p>Acid attack without cavitation.</p> Signup and view all the answers

    What is observed in the zone of hypermineralization in dentinal lesions?

    <p>An increase in mineral density.</p> Signup and view all the answers

    Which component forms the bulk of the dentin matrix?

    <p>Dentin tubules.</p> Signup and view all the answers

    What occurs in the zone of fatty degeneration during dentinal caries?

    <p>Odontoblastic processes collapse due to acid irritation.</p> Signup and view all the answers

    How much of the dentin's composition is made up of organic material?

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

    Signup and view all the answers

    Signup and view all the answers

    Study Notes

    Dental Caries Definition and Etiology

    • Dental caries is a progressive microbial disease affecting hard tooth structures.
    • It's characterized by demineralization of the inorganic portion and destruction of the organic substance of the tooth.
    • Contributing factors to dental caries:
      • Cariogenic bacteria (agent)
      • Fermentable carbohydrates (substrate)
      • Susceptible tooth and saliva (host)
      • Time
      • Means of microorganism and substrate localization on tooth surfaces (dental plaque).

    Role of Bacteria in Dental Caries

    • Cariogenic bacteria produce acids from the fermentation of carbohydrates.
    • These acids lead to enamel and dentin demineralization.

    Experiments Demonstrating the Role of Cariogenic Microorganisms

    • Miller's experiment demonstrated that caries-like lesions form in saliva when carbohydrates are added.
    • Caries result from carbohydrate fermentation by bacteria in saliva.
    • Initial experiment established that bacteria is necessary for caries formation.
    • Orland's experiment showed that germ-free animals don't develop caries, concluding bacteria is essential for caries formation.

    Production of Gnotobiotes

    • Aim: to determine which bacteria produce dental caries.
    • Rats were divided into groups and fed specific micro-organisms (streptococci, staphylococci, lactobacilli, etc.).
    • Streptococcus mutans produced smooth surface and pit-and-fissure caries.
    • Lactobacilli produced pit-and-fissure caries.
    • Not all bacteria cause dental caries.
    • Streptococcus mutans is more cariogenic than lactobacilli.

    Essential Features for Cariogenic Bacteria

    • Ability to produce acids (acidogenic).
    • Ability to survive in acidic environments (aciduric).
    • Synthesis of insoluble extracellular polysaccharides (dextrans and levans).
    • Synthesis and utilization of intracellular storage polysaccharides (amylopectin).
    • Ability to actively transport fermentable sugars.
    • Attachment mechanisms for firm adhesion to tooth surfaces.

    Cariogenic Bacteria: Streptococcus Mutans and Lactobacillus Species

    • Streptococcus mutans:
      • Acidogenic, acid-tolerant.
      • Synthesizes extracellular polysaccharides (dextrans and levans) for adhesion.
      • Undergoes morphological mutations with changing environmental conditions (pH).
    • Lactobacillus species:
      • Acidogenic, acid-tolerant.
      • Can only produce pit and fissure caries in gnotobiotic animals.
      • Do not produce extracellular polysaccharides for adhesion.

    Role of Fermentable Carbohydrates

    • Types of carbohydrates: monosaccharides (e.g., glucose, fructose), disaccharides (e.g., sucrose, maltose, lactose), and polysaccharides (e.g., starch, glycogen).
    • Sucrose is the most cariogenic carbohydrate.
    • Sucrose is cheap, highly available, low molecular weight and dissolves easily into dental plaque.
    • Bacterial enzymes rapidly break down sucrose producing acids.
    • Sucrose with the help of cariogenic bacteria (e.g., Streptococcus mutans) forms extracellular polysaccharides (dextran & levan).

    Refinement of Carbohydrate

    • Refinement of carbohydrates increase cariogenicity.
    • Refinement increases the concentration of fermentable carbohydrates.
    • Refinement removes fibrous material increasing adhesiveness.
    • Xylitol, a refined carbohydrate, is not cariogenic.
    • Honey is cariogenic despite not being refined.

    Vipeholm Experiment

    • Aim: to determine the effect of the amount, frequency, and texture of carbohydrates on caries susceptibility.
    • High caries activity correlated with frequent intake of sticky carbohydrates.
    • Caries in groups consuming sugar between meals was less severe than consumption between meals.

    3. Dental Plaque

    • Definition: a tenacious bacterial structure formed on tooth surfaces.
    • Composition: Microorganisms, proteins, carbohydrates, and inorganic content.
    • Role of plaque matrix: acts as a diffusion-limiting membrane, slow down saliva action & contributes to adhesiveness.
    • Factors affecting formation & thickness: Tooth anatomy, appliances, surface structure, friction, oral hygiene measures, and diet.

    Mechanism of Bacterial Plaque Formation

    • Formation of an acquired enamel pellicle (acellular).
    • Colonization of cell-free pellicle by pioneer bacteria.
    • Rapid growth phase of bacteria spreading across the tooth surface.
    • Formation of an intermediate/mature community.
    • Selective replacement of microbes in the mature community.

    Microbial Succession

    • Aciduric organisms (e.g., Streptococcus mutans (positive interaction)) proliferate, while less aciduric organisms such as S. sanguis (negative interaction) disappear.
    • Aerobic species are replaced by anaerobic species.

    Biochemical Reactions in Bacterial Plaque

    • Acid production.
    • Formation of extracellular and intracellular polysaccharides.
    • Demineralization and remineralization phases.

    Stephan's Experiment

    • Aim: to study pH changes in plaque after glucose intake.
    • pH rapidly decrease within 2-5 minutes of glucose ingestion.
    • Return to resting pH is slow and depends on caries activity.

    Demineralization and Remineralization

    • Caries is an alternating process of demineralization and remineralization.
    • Remineralization occurs when the consumption of fermentable sugars stops and oral hygiene improves.

    Host Factors: Susceptible Tooth

    • Position (upper/lower, anterior/posterior, aligned/malaligned teeth).
    • Morphology (pits and fissures are more susceptible to caries).
    • Structure (enamel hypoplasia, hypocalcification).
    • Fluoride (higher fluoride content increases resistance to caries).

    Host Factors: Saliva

    • Salivary glycoproteins initially protect enamel.
    • Saliva helps cleanse the mouth.
    • Salivary buffers neutralize acidic pH.
    • Lower saliva flow rates increase caries incidence.

    Pathology of Dental Caries

    • Macroscopic appearance: opaque chalky white areas (white spots).
    • Microscopic changes: demineralization and remineralization phases.
    • Phases of enamel caries: initiation, bacterial invasion, destruction, and secondary enamel caries.
    • Dentin caries: initial non-bacterial lesions, acid attack on dentinal tubules leading to acid-induced demineralization.

    Methods to Identify Initial Enamel Caries

    • Ordinary light microscope, polarizing light microscope, microradiography, and microhardness testing.

    Zones in Longitudinal Ground Sections of Enamel

      1. Translucent zone: initial demineralization, appears translucent.
      1. Dark zone: further demineralization.
      1. Body of the lesion: most demineralization.
      1. Surface zone: remineralization zone.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Dental Caries Handout PDF

    Description

    Test your knowledge about the relationship between carbohydrates and dental caries. This quiz covers the cariogenicity of different types of carbohydrates, the role of bacteria, and the impact of carbohydrate intake on dental health. Explore the factors influencing dental plaque formation and caries susceptibility.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser