Dental Caries- Histoplathology

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Dental Caries- Histoplathology

• Dr. Rhythm
• Assistant Professor

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• CARIES OF DENTIN
• Begins with the natural spread of the process
  along the DEJ and rapid
• involvement of the dentinal tubules. The dentinal
  tubules act as tracts leading to the pulp (path
  for micro-organisms).

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Caries of Dentin
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• Early Dentinal Changes
• -initial penetration of the dentin by caries?
  dentinal sclerosis,
• -calcification of dentinal tubules and sealing
  off from further penetration by
• micro-organisms,
• -more prominent in slow chronic caries.

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In the earliest stages, when only few tubules are
involved, microorganisms may be found penetrating
the tubules? Pioneer Bacteria.
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This initial decalcification involves the walls
allowing them to distend as the tubules are
packed with microorganisms. Each tubule is seen
to be packed with pure forms of bacteria, eg.,
one tubule packed with coccal forms the other
tubule with bacilli.
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Advanced Dentinal Changes -decalcification of
walls, confluence of the dentinal tubules, -tiny
liquefaction foci, described by Miller are
formed by the focal coalescing and breakdown of
dentinal tubules. These are ovoid areas of
destruction parallel to the course of the tubules
which filled with necrotic debris and increase in
size by expanding. The adjacent tubules are
distorted and their course is bent due to this
expansion.
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As the microorganisms proceed further they are
distanced from the carbohydrates substrate that
was needed for the initiation of the caries.
Thus the high protein content of dentin must
favour the growth of the microorganisms.
Therefore proteolytic organisms might appear to
predominate in the deeper caries of dentin while
acidophilic forms are more prominent in early
caries.
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• Shape of the lesion is triangular with the apex
  towards the pulp and the base towards the enamel.
• Zone 1 Zone of Fatty Degeneration of Tomes
  Fibers,(next to pulp)
• -due to degeneration of the odontoblastic
  process. This occurs before sclerotic dentin is
  formed and makes the tubules impermeable.

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• Zone 2 Zone of dentinal sclerosis,
• -deposition of Ca salts in the tubules.
• Zone 3 Zone of decalcification of dentin
• Zone 4 Zone of bacterial invasion
• Zone 5 Zone of decomposed dentin due to acids
  and enzymes.

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Root Caries

• Root caries as defined by HAZEN, is a soft,
  progressive lesion that is found anywhere on the
  root surface that has lost its connective tissue
  attachment and is exposed to the environment.
• -the root surface must be exposed to the oral
  environment before caries can develop here.
• -Plaque and micro-organisms are essential for the
  cause and progression of the lesion, mostly
  Actinomyces,
• -micro-organisms invade the cementum either along
  the Sharpeys fibers or between the bundles of
  fibers.

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• -spread laterally, since cementum is formed in
  concentric layers.
• -after decalcification of cementum, destruction
  of matrix occurs similar to dentin with ultimate
  softening and destruction of this tissue.
• -invasion of micro-organisms into the dentinal
  tunbules, finally leading to pulp involvement.
• -the rate is slower due to fewer dentinal tubules
  than crown area

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Importance of Early Caries Detection
Importance of early caries detection
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• Objectives of diagnosis
• Identifying lesions requiring surgical treatment
• Identifying lesions requiring non-surgical
  treatment
• Persons at high risk for developing caries
• Thus diagnosis is done using
• Clinical criteria
• Tools
• Newer refined diagnostic tools

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VISUAL EXAMINATION
Most widely used method, in dental offices, in
clinical research and in epidemiological studies.

• Quick, cheap and easy.

• Should be performed on a dry, clean tooth, with
  good light, with a mirror.

Wet
Dry
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Role of Magnification in Determining Cavitation
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• Dental floss may be employed to detect proximal
  caries.

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TACTILE METHOD

• Sturdevants (1985)
• Defects are best detected when an explorer placed
  into a pit or fissure provides tug-back or
  resistance to removal.
• Subject of controversy
• Use of the explorer does not add anything to the
  detection yield of the examination.
• The use of the explorer may at best be misleading
  and at worst be potentially damaging

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RADIOGRAPHY

• The purpose of the radiograph is to detect
  lesions that are clinically hidden from careful
  visual examination.
• ADVANTAGES
• Discloses sites inaccessible to other methods
• Detects at early , reversible stage
• Depth of lesion can be evaluated and scored by
  index given by Grondahl et al (1977)
• Permanent record

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BITE WING RADIOGRAPHS

• When radiography is applied in the clinic for
  caries detection, the recommended technique is
  bitewing projection (Gröndahl, 1994).
• Disadvantages
• Not convincingly able to distinguish between
  cavitated and noncavitated surfaces (Nielsen et
  al., 1996)

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XERORADIOGRAPHYBY CARLSON 1937

• Image is recorded on an aluminium plate coated
  with a layer of selenium particles which have a
  uniform electrostatic charge
• X-rays cause selective discharge from the
  particles, forming a latent image, which is
  developed to a ve image by developing
• Advantages
• Twice as sensitive as conventional D-speed films
• Edge enhancement is possible

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DIGITAL RADIOGRAPHY
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QLF, THE QUANTITATIVE LIGHT INDUCED FLUORESCENCE
METHOD

• The science behind this phenomenon appears to be
  the increased fluorescence exhibited by
  cariogenic bacterial metabolites within the
  lesion, as well as the changed fluorescent nature
  of the lesion itself.

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ENHANCED VISUAL TECHNIQUES

• FIBER OPTIC TRANS-ILLUMINATION( FOTI)
• Principle decayed matter scatter light more
  strongly-lower index of light transmission
• Can be used in all surfaces, particularly useful
  at proximal lesions

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DYES USED FOR CARIES DIAGNOSIS

• Dyes can visualize a subject from its routine
  background by colour.
• The observation can be qualitative or
  quantitative.
• Dyes should be
• -safe for intra-oral use
• -stain the tissues that are diseased
• -should be easily removed

Vista red, Vistadental
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DYES IN CARIES DETECTION

• Carious Enamel Procion, Calcein, Brilliant
  Blue is used.
• Dentin caries Basic fuchsin , Methylene blue,
  Acid red.
• Modified dye preparation uses iodine.
• It measures enamel porosity in incipient carious
  lesions Bakhos et al.(1977)
• Uses iodine as potassium iodide.

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DIGITAL RADIOGRAPHY

• A digital imaging is an image formed and
  represented by a spatially distributed set of
  discrete sensors and pixels
• when viewed from a distance the image appear
  continuous, but on closer inspection it has
  individual pixels.

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Caries detecting dyes stain infected carious
dentin, but also stain the demineralized organic
matrix of carious dentin, which should not be
removed.
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• Q. 1 Bactria found in initial dentinal caries are
  called
• A. Initial bacteria
• B. Frontier bacteria
• C. Pioneer Bacteria
• D. Premier bacteria

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• Q.2 Dentinal sclerosis is seen in
• A. slowly progressing caries
• B. Acute caries
• c. Incipient caries
• D. irreversible caries

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• Q.3 Liquefaction foci can be seen in
• A. Advanced caries
• B. Initial caies
• C. Rampant caries
• D. Incipient caries

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• Q.4 Early caries is associated with
• A. Predominantly acidogenic bacteria
• B. Proteolytic bacteria
• C. Premier bacteria
• D. acidophillic bacteria

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• Q.5 Zone of fatty degeneration is
• A. Zone 1
• B. Zone 2
• C. Zone 3
• D. zone 4

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• Q. 6 Root caries is caused due to
• A. Actinomyces
• B. Lactobacillus
• C. Streptococcus
• D. Staphylococcus

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• Q.7 QLF is based on
• a. Fluorescence
• b. Absorption
• c. Scatter
• d. Radiation

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• Q.8 Bite wing radiographs are best for
• a. Visualising perapical area
• b. Proximal caries
• c. Occlusal caries
• d. Root caries

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• Q.9 Root caries is caused by
• a. Actinomyces
• b. Lactobacilli
• c. Streptococcus
• d. Staphylococcus

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• Q.10 Dental floss is used for detecting
• a. proximal caries
• b. occlusal caries
• c. root caries
• d. enamel caries