M1 | Histopathology of Dental Caries [COMPLETE]

acquired enamel pellicle (AEP)

formed primarily from the selective precipitation of various components of saliva

• rough surface caused by caries lesion

• a poor quality restoration

• a structural defect

what restricts biofilm removal?

• silver

• peptides

• tin

• antimicrobials

strategies that modulate a dysbiotic microbiome

Oral Biofilm

complete and accurate description of its composition (bio) and structure (film)

• microorganisms

• their byproducts

• extracellular matrix

• water

4 components of Oral Biofilm:

healthy symbiosis

microorganisms striving in neutral pH

not found elsewhere in nature

many of the microorganisms found in the mouth are

ability to adhere to a surface

survival of microorganisms in the oral environment depends on their

free-floating organisms

are cleared rapidly from the mouth by salivary flow and frequent swallowing

streptococci

example of a few specialized organisms that are able to adhere to oral surfaces such as mucosa and tooth structure

mucosa and tooth structure

few specialized organisms like streptococci are able to adhere to oral surfaces such as:

700 different species of bacteria

over [BLANK] have been identified in the oral biofilm

higher

oral biofilm from healthy teeth have a (higher or lower?) diversity than from carious teeth

mature biofilm communities

are capable of rapid anaerobic metabolism of any available carbohydrate

acidic regions with mature biofilm communities

acidic regions in the biofilm that are not neutralized by saliva buffers

biofilm that are not neutralized by saliva buffers

resulted in acidic regions with mature biofilm communities that are capable of rapid anaerobic metabolism of any available carbohydrate

pits and fissures on the crown

distinct habitat that has a simple population of streptococci

root surface in the gingival sulcus

distinct habitat that has a complex community dominated by filamentous and spiral bacteria

simple population of streptococci

microorganisms in pits and fissures on the crown

complex community dominated by filamentous and spiral bacteria

microorganisms in root surface in the gingival sulcus

distal surface

carious; may have a biofilm dominated by large populations of mutans streptococci (MS) and lactobacilli

populations of mutans streptococci (MS) and lactobacilli

populations that dominate distal surface

mesial surface

may lack these organisms and be caries free

organic acid byproducts

some bacteria in the biofilm, metabolize carbohydrates for energy and produce

organic acids

can lower the pH in the biofilm to below a critical level

- 5.5 for enamel

- 6.2 for dentin

organic acids can lower the pH in the biofilm to below a critical level in enamel and dentin by:

low pH

has effects both on the biofilm composition and at the tooth surface level

dental plaque

dental biofilm is historically termed as this to describe this soft, tenacious film accumulating on the surface of teeth

• adherent food debris

• a result from haphazard collection of opportunistic microorganisms

Oral Biofilm is not:

professional tooth cleanings

are intended to control the biofilm plaque and prevent caries, so they are important to avoid the maturation of biofilm, reducing the risk for dental caries formation

oral prophylaxis (done every 6 months) / scaling and polishing

examples of professional tooth cleanings

within 2 hours

a cell-free, organic film, the acquired enamel pellicle (AEP) can cover the previously denuded area completely

tooth habitat for cariogenic biofilm

the tooth surface is covered with pellicle of precipitated salivary glycoproteins, enzymes and immunoglobulins, it is the ideal surface for the attachment of many oral streptococci and if left undisturbed biofilm rapidly builds up to sufficient depth to produce an anaerobic environment adjacent to tooth surface → the

• to protect the enamel

• to reduce friction between teeth

• to provide a matrix for remineralization

3 functions of the pellicle:

pellicle

facilitator of bacterial for remineralization

• pits and fissures

• smooth enamel surfaces

2 usual surfaces as tooth habitat for cariogenic biofilm:

pits and fissures

particularly susceptible surfaces for caries lesion initiation

S. Sanguis and other streptococci

pits and fissures provide excellent mechanical shelter for organisms and harbor a community dominated by

smooth enamel surfaces (proximal)

proximal enamel surfaces immediately gingival to the contact area - second most susceptible areas to dental caries lesions

proximal (distal and mesial)

most prone among smooth enamel surfaces

pits and fissure

most susceptible to dental caries (generally)

mastication, tongue movement and salivary flow

smooth enamel surfaces are protected physically and are relatively free from the effects of

dental caries lesions

result from a dynamic process of damage (demineralization) and restitution (remineralization) of the tooth matter at tooth surface and subsurface level

demineralization and remineralization

take place several times a day over the life of the tooth

demineralization

low pH drives calcium and phosphate from the tooth to the biofilm in an attempt to reach equilibrium, resulting in a net mineral loss by the tooth or

(-) calcium and phosphate

demineralization

acidogenic and acidophilic microorganisms

predominant in extended periods of low pH

remineralization

concentration of soluble calcium and phosphate is supersaturated relative to that in the tooth; minerals can then be added back to partially demineralized enamel in a process called

(+) calcium and phosphate

remineralization

neutral

pH during remineralization

• number and type of microbial flora in the biofilm

• diet

• oral hygiene

• genetics

• dental anatomy

• dentin and enamel composition

• use of fluorides and other chemotherapeutic agents

• saliva composition

• saliva flow

• buffering capacity

Example of factors that modulate demineralization and remineralization (give 5 only):

• person to person

• tooth to tooth in the same individual

• site to site on a same tooth

These factors (in D&R) are highly individual and tooth specific and differ from:

acidogenic or acidophilic

with constant exposure to factors that promote caries, from symbiotic, microorganism will transform into

repeated demineralization

may cause localized dissolution and destruction of the calcified dental tissues → caries lesion

caries lesion

resulted from repeated demineralization

cavitation in the enamel surface

collapse of the surface from demineralization at the enamel subsurface level

dentin cavitation

due to demineralization of the inorganic phase (dentin mineral) and denaturation and degradation of the organic phase (primary dentin collagen)

• saliva flow and components

• remineralization (fluoride, calcium, phosphate)

• good oral hygiene

• strategies that maintain a healthy microbiome (probiotics, prebiotics, arginine, pH modifiers, erythritol and xylitol)

• strategies that modulate a dysbiotic microbiome (silver, peptides, tin, antimicrobials)

caries balance: 5 protective factors

• probiotics

• prebiotics

• arginine

• pH modifiers

• erythritol

• xylitol

strategies that maintain a healthy microbiome

• acid-producing bacteria

• sub-normal saliva flow and/or function

• frequent eating/drinking of fermentable carbohydrates

• poor oral hygiene

caries balance: 4 pathological factors

remineralization

protective factors can lead to

demineralization

pathological factors can lead to

Caries Lesion Progression

depends on the site of origin and conditions in the mouth

18 months (± 6 months)

from a non-cavitated caries lesion to a cavitated caries lesion on smooth surfaces

3 years after eruption of the tooth

peak rates for incidence of new lesions

less time

occlusal pit-and-fissure lesions develop in (MORE TIME or LESS TIME?) than smooth-surface caries lesions

3 weeks

poor oral hygiene and frequent exposures to sucrose-containing or acidic food can produce non-cavitated initial ("white spot") lesions in

usually slow

caries lesion progression in healthy individuals is (USUALLY FAST or USUALLY SLOW) compared with the progression in compromised persons

3 months

radiation related caries may develop in how many months after radiation-induced hyposalivation (dry mouth) due to radiation therapy?

initial lesion

earliest evidence of enamel caries lesion; non-cavitated enamel caries lesions

white spots

[BLANK] of initial caries must be distinguished from developmental white spot hypocalcification or other developmental defects of enamel

initial (white spot) caries lesion

partially or totally disappear visually when the enamel is wet

hypocalcified enamel

is affected less by drying and wetting

facial and lingual surfaces of teeth

initial (white spot) caries lesion is usually observed on the

5 seconds

chalky white, opaque areas can be seen after drying the tooth for

desiccated

initial lesion is seen only when the tooth surface is

demineralization

areas of enamel lose their translucency because of the extensive subsurface porosity caused by

ICDAS CODE 1 or ADA INITIAL CARIES

initial lesion in ICDAS or ADA CSS

advanced lesion

- irregular surface that is rougher than the unaffected normal enamel

- with softened chalky enamel that can be chipped away with an explorer

- sign of active caries

rougher

irregular surface that is (ROUGHER or SMOOTHER) than the unaffected normal enamel

explorer

advanced lesion has a softened chalky enamel that can be chipped away with an

active caries

advanced lesion is a sign of what type of caries

ENAMEL

usual site of initial lesion

gingival recession

unless dentin or cementum becomes exposed by [BLANK], then the attack will proceed there

initial lesion

earliest evidence of enamel caries lesion

white spots

partially or totally disappear visually when the enamel is wet; “suddenly” appeared

hypocalcified enamel

affected less by drying and wetting; developed slowly or long term

facial and lingual surfaces of teeth

initial caries is usually observed in:

5 seconds

chalky white, opaque areas can be seen after drying the tooth for:

desiccated

initial lesion is seen only when the tooth surface is:

demineralization

areas of enamel lose their translucency because of the extensive subsurface porosity caused by

subsurface of enamel

the most external part of enamel comes in contact with calcium, phosphate and brushing action; hence it is not much affected by demineralization unlike:

ICDAS CODE 1 or ADA INITIAL CARIES

classification of initial lesion in ICDAS and ADA CSS

advanced lesion

irregular surface that is rougher than the unaffected normal enamel

ball ended instrument

advance lesion has softened chalky enamel that can be chipped away but should be kept for it to be remineralized again, so this instrument is used

active caries

what type of caries is advanced lesion a sign of?

surface enamel

affected by advance lesion

porosities and small cavitation

advanced lesion is different from the beginning, it has:

topical fluoride

treatment for advanced lesion

ICDAS CODE 2 and 3

classification of advanced lesion in ICDAS