M1 | Histopathology of Dental Caries Pt. 2

Enamel Caries | Dentin Caries | Root 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

pits and fissures caries

what kind of enamel caries is this?

pyramidal, triangular or conical

shape of pits and fissures caries

going towards the pits and fissures

apex of pits and fissures caries

going to the DEJ

base of pits and fissures caries

smooth surface caries

what kind of enamel caries is this?

pyramidal, triangular or conical

shape of smooth surface caries

going to the DEJ

apex of smooth surface caries

going to the surface enamel

base of smooth surface caries

proximal caries

most common caries that form on the smooth surfaces because it is between adjacent teeth; thus it is protected from: mastication, tongue movement or salivary flow

• plain transmitted light

• polarized light-clearer picture

smooth surface caries can be viewed microscopically in:

• pits and fissures caries

• smooth surface caries

enamel caries that follow the direction of the enamel rods

• early submicroscopic lesion

• phase of non-bacterial enamel crystal destruction

• cavity formation

• bacterial invasion of enamel

• undermining of enamel

five stages of enamel caries

subsurface enamel

once affected by the acid does not remineralized as much as the exposed enamel, hence they are affected greatly

carbohydrates

acid producing microorganism will act upon:

demineralization

metabolized carbohydrates result in acid that will cause:

laterally

demineralization will cause microcavitation for caries with MGs to enter the tooth, subsequently DEJ and spread:

smooth surface enamel (proximal)

zones in enamel caries are found and more appreciated in:

• ZONE 4 | Surface Zone

• ZONE 3 | Body of the Lesion

• ZONE 2 | Dark Zone

• ZONE 1 | Translucent Zone

four zones in enamel caries

ZONE 4 | Surface Zone

ZONE OF ENAMEL CARIES

• less demineralized

• outermost zone; most superficial zone

calcium and phosphorus

zone 4 of enamel caries has the highest amount of mineral content with saliva and biofilm rich in:

plaque and saliva

zone 4 of enamel caries is the area of active re-precipitation of minerals derived from both:

9.9%

mineral reduction in ZONE 4 | Surface Zone

less than 5%

pore volume in ZONE 4 | Surface Zone

ZONE 3 | Body of the Lesion

ZONE OF ENAMEL CARIES

• area with greatest demineralization due to marked band of Retzius

24%

mineral reduction in ZONE 3 | Body of the Lesion

10-25% in central part; 5% at the periphery

pore volume in ZONE 3 | Body of the Lesion

relatively unaffected surface layer and the dark zone

ZONE 3 | Body of the Lesion lies between the:

negative birefringence

ZONE 3 | Body of the Lesion is the zone of:

penetrated some way into the dentin

the surface zone remains intact and also well mineralized because it is a site were calcium and phosphate ion released by subsurface dissolution, become reprecipitated, eventually the surface zone is demineralized usually at the stage when the lesion has:

ZONE 2 | Dark Zone

ZONE OF ENAMEL CARIES

• a result of demineralization that appears dark brown with presence of small pores in ground section surrounding the body of the lesion and lies adjacent to the translucent zone

dark brown

color of ZONE 2 | Dark Zone

body of the lesion

ZONE 2 | Dark Zone surrounds the:

translucent zone

ZONE 2 | Dark Zone lies adjacent to:

85-90%

ZONE 2 | Dark Zone has positive birefringence in [BLANK] of the lesions which may be due to the arrest of microorganism

2-4% of spaces

pore volume in ZONE 2 | Dark Zone

6% per unit volume

mineral reduction in ZONE 2 | Dark Zone

“positive zone”

ZONE 2 | Dark Zone is usually present thus referred to as:

ZONE 1 | Translucent Zone

ZONE OF ENAMEL CARIES

• not always present

• zone of reaction found in enamel

• white area adjacent to the dark zone

• lies at the advancing front of the lesion

• slightly more porous than sound enamel

advancing front of the lesion

translucent zone lies at the:

prism boundaries and other junctional sites

spaces or pores created in the tissue at zone 1 of enamel caries are located at:

white opaque

earliest visible changes of early lesion in proximal

lateral walls of the fissure

initial lesions of pits and fissures caries develop on the

remineralization of enamel surface

initial cavitation of the opposing walls of the fissure is not seen on the occlusal surface due to:

pits and fissures caries

• more tubules will be involved because its base going to the DEJ is wider and will spread laterally

1. what produce greater cavitations as compared to smooth surface caries?

2. why?

A | progression of pits and fissures caries

• The initial lesions develop on the lateral walls of the fissure.

• Demineralization follows the direction of the enamel rods, spreading laterally as it approaches the dentinoenamel junction (DEJ).

B | progression of pits and fissures caries

• Soon after the initial enamel lesion occurs, a reaction can be seen in the dentin and pulp.

• Forceful probing of the lesion at this stage can result in damage to the weakened porous enamel and accelerate the progression of the lesion.

• Clinical detection at this stage should be based on observation of discoloration and opacification of the enamel adjacent to the fissure.

• These changes can be observed by careful cleaning and drying of the fissure.

C | progression of pits and fissures caries

• Initial cavitation of the opposing walls of the fissure cannot be seen on the occlusal surface.

• Opacification can be seen that is similar to the previous stage.

• Remineralization of the enamel because of trace amounts of fluoride in the saliva may make progression of pit-and-fissure lesions more difficult to detect.

D | progression of pits and fissures caries

Extensive cavitation of the dentin and undermining of the covering enamel darken the occlusal surface

DENTIN CARIES LESION

V-shaped in cross section with a wide base at the DEJ and the apex directed to the pulpal cavity

• presence and orientation of dentinal tubules

• less minerals, more organic content as compared to enamel

• area of dentin would have cavitation later on

dentin caries lesion advance more rapidly than enamel caries lesion because:

dentinal tubules

provide a pathway for the ingress of bacteria and egress of minerals

DEJ’s lower mineral content as compared to primary dentin

“when enamel demineralization advances to the DEJ, rapid lateral spread or expansion of the caries lesion along the DEJ may occur if there is bacterial contamination” this was attributed to:

DEJ’s high concentration of Matrix Metalloproteinases (MMPs)

“when enamel demineralization advances to the DEJ, rapid lateral spread or expansion of the caries lesion along the DEJ may occur if there is bacterial contamination” this is attributed to:

area of the DEJ

high concentration of Matrix Metalloproteinases (MMPs) can be found in the:

Matrix Metalloproteinases (MMPs)

enzymes related to tissue healing/re-modelling and now implied in dentin caries lesion progression

• beaded dentin

• oblong cleft

• transverse cleft

seen in advance dentin caries:

beaded dentin

string of pearls

length of dentinal tubules

beaded dentin is found within the:

small beads on string

microscopic view of beaded dentin:

1 dentinal tubule along its length

affected in beaded dentin

distension on the walls of dentinal tubules

seen in beaded dentin

oblong cleft

• 2 or more dentinal tubules will be affected, coalesce or fuse because of MGs that will result in one big cavity or area with MGs

• adjacent dentinal tubules will have the same condition as the beaded dentin

• parallel to the direction of dentinal tubule

• the center will be the most affected - necrotic area

2 or more dentinal tubules

affected in oblong cleft

direction of dentinal tubule

oblong cleft is parallel to the:

center

which area will be the most affected (most necrotic) in oblong cleft?

transverse cleft

• area perpendicular to dentinal tubules

• lateral branching of the dentinal tubules

• microorganism inside the dentinal tubules will occupy that area

globular dentin

in transverse cleft [BLANK] is present, meaning there is not enough calcification near area of dentinal tubules

• ZONE 0 | Zone of Retreating Odontoblastic Process

• ZONE 1 | Zone of Fatty Degeneration of Odontoblast Process

• ZONE 2 | Zone of Dentinal Sclerosis

• ZONE 3 | Zone of Decalcification of Dentin

• ZONE 4 | Zone of Bacterial Invasion of Decalcified but Intact Dentin

• ZONE 5 | Zone of Decomposed Dentin

six zones of dentinal caries

ZONE 0 | Zone of Retreating Odontoblastic Process

ZONE OF DENTIN CARIES

• not the first zone, but happens in the innermost zone before the cycle starts again

ZONE 1 | Zone of Fatty Degeneration of Odontoblast Process

ZONE OF DENTIN CARIES

• preparation for sclerosis

fat globules

ZONE 1 | Zone of Fatty Degeneration of Odontoblast Process

• disposition of [BLANK]

  • receded early sclerotic changes

  • fat contributes to impermeability

  • predisposing factor for dental sclerosis

odontoblast process

inside dentinal tubules

no sclerosis

no fatty deg. =

ZONE 2 | Zone of Dentinal Sclerosis

ZONE OF DENTIN CARIES

• characterized by deposition of calcium salts in the dentinal tubules

ZONE 3 | Zone of Decalcification of Dentin

ZONE OF DENTIN CARIES

• a narrow zone, receding bacterial invasion

• there’s no microorganisms yet, only their byproducts

ZONE 4 | Zone of Bacterial Invasion of Decalcified but Intact Dentin

ZONE OF DENTIN CARIES

• happens after they’ve been given a portal of entry via decalcification or demineralization

ZONE 5 | Zone of Decomposed Dentin

ZONE OF DENTIN CARIES

• the bacteria that invaded will destroy organic substances leading to decomposition of dentin

• continuous cycle of this will lead to a more visible necrotic area of dentin

• proximal root surface

• facial/lingual/buccal/ surface

2 possible location of root caries lesion

proximal root surface

most common area of root caries lesion

• gingival recession → exposed root

• concaved surface contour

• occasional roughness in CEJ

proximal root surface near the cementoenamel junction is often unaffected by the action of hygiene procedures such as flossing and favor the formation of mature, cariogenic biofilm and proximal root surface caries lesions due to:

• negligence in hygiene procedures (like brushing)

• protection from friction during mastication

• presence of cariogenic biofilm

caries form in facial/lingual/buccal root surfaces due to:

• gingival recession → exposed root

• concaved surface contour

• occasional roughness in CEJ

root caries are caused by: