Day 3 lecture 2

Question 1

Know major cariogenic bacteria

Answer 1

Know major cariogenic bacteria

Question 2

3 sites for caries initiation

Answer 2

Different lesions at different sites.

1. Pit and fissures
2. Smooth enamel surfaces
3. Root surfaces

Question 3

Pits and fissures

Answer 3

Bacteria - pits and fissures are difficult to clean. Gram + cocci S. sanguis in particular, are found in the pits and fissures of newly erupted teeth, large numbers of MS are found in carious pits and fissures.
Physically like an inverted V. Small and spreads out once it hits dentin.

Question 4

Progression of caries - pits and fissures

Answer 4

Progresses along enamel rods (why it is angular and spreads).

Question 5

Enamel lesion

Answer 5

Decay in enamel - E1 if less than halfway through. More than halfway = E2. Doesn’t depend on dentin decay.

Question 6

“Watch”

Answer 6

Don’t cut. What you can do is have flouride treatment, watch diet.

Question 7

Entering dentin

Answer 7

After initial lesion occurs, reaction can be seen in the dentin and pulp. **Forceful probing at this stage can result in damage to weakened porous enamel and accelerate the lesion progress. Class 1 is usually performed here.

Question 8

Deeper into dentin

Answer 8

initial cavitation of the opposing walls of the fissure cannot be seen occlusally. Before it gets through DEJ, you do not need to remove. Opacification occurs similarly. Remineralization can make detecting this difficult

Question 9

Remineralization

Answer 9

Requires a good vital functioning blood supply in the pulp.

Question 10

Moving into pulp

Answer 10

Occlusal surface darkens significantly.

Question 11

Smooth enamel surface

Answer 11

Present a less favorable site for biofilm attachement, but distal/mesial surfaces below contact points, and below HOC you have protected areas that can decay. Once DEJ is penetrated, caries spreads laterally and down.

Question 12

Dentin decay

Answer 12

D1 - first third or so, D2 - rest of the way. Cut on D1 and D2. D2 usually crowned.

Question 13

Root surfaces

Answer 13

Rougher than enamel - biofilm builds up more quickly. Cementum is extremely thin, not as mineralized, do not have well-defined margins. Just look like mush. Critical pH for dentin is higher than for enamle. Likely to start before the pH reaches the critical level for enamel (pH 5.5). Tend to be U shaped in cross-section. This has increased as more older people retain more teeth.

Question 14

Progression of caries lesions

Answer 14

Progression/morphology varies. Usually a year to 2 years to develop a cavity. Peak rates of incidence is 3 years after tooth eruption. Occlusal pit and fissure lesions take less time/we can’t tell if they’re there. Poor hygeine and frequent exposure to acidic/sugary food leads to white spot lesions in potentially 3 weeks.

Question 15

Xerostomia

Answer 15

Head and neck radiation loses salivary glands.

Question 16

Enamel Caries histopathology

Answer 16

Dark zone - bacteria. When it is remineralizes, it is still very dark and shiny. This is due to a combination of things contained in it.
Translucent zone - beginning to demineralize.

Question 17

Enamel caries variety

Answer 17

Hypocalcified enamel (undercalcified- look white and opaque). Don’t go away when wet. Do not restore unless aesthetic.
White spot lesion (noncavitated lesion). If you get them wet, they disappear. If they are dry you can see it.
Cavitated enamel lesion (active caries). Connection between outside of tooth and dentin.
Remineralized enamel lesion (inactive caries). Usually are dark - occlusions/impurities in them. Dark zone causes this.

Question 18

Hypocalcified enamel

Answer 18

(undercalcified- look white and opaque). Don’t go away when wet. Do not restore unless aesthetic (patient wants it).

Question 19

White spot lesion

Answer 19

(noncavitated lesion). If you get them wet, they disappear. If they are dry you can see it. Hard external surface. Do not restore*** Proximal lesions in enamel. Most original crystal framework is here, aids in remineralization.

Question 20

Cavitated enamel lesion

Answer 20

(active caries). Connection between outside of tooth and dentin. Restoration needed, as original framework is gone. Bigger in mouth than on x-ray

Question 21

Remineralized enamel lesion

Answer 21

(inactive caries). Usually are dark - occlusions/impurities in them. Dark zone causes this. Supersaturation of saliva w/Ca and P. Presence of flouride is best. New decay here is extremely rare.

Question 22

Kissing lesions

Answer 22

Mesial/distal surfaces of teeth share adjacent lesions.

Question 23

Cervical burnout

Answer 23

Tooth narrows, doesn’t have as much density.

Question 24

Enamel caries summary **

Answer 24

Know this slide* - add all

Question 25

Normal enamel

Answer 25

Hydrated:
Desiccated:
Surface texture:
Surface Hardness:

Question 26

More pain from

Answer 26

Enamel to dentin. As it goes further into dentin, there is less pain. Little response to pain in Dentin.

Question 27

Dentinal caries

Answer 27

Softer, partially demineralized, still remineralizable. Bacteria near to peritubular dentin. Zone 3 = infected dentin. Zone 2 = effected dentin. Peels off in layers parallel to DEJ. Crystallites appear in dentin, appear to occlude preventing bacteria. Zone 1 = normal dentin.

Question 28

Pulp-dentin complex react to caries attack

Answer 28

1. long term low level - pulp responds by building reparative dentin. Direct exposure to microorg is not needed for pulp to react. It can also hypermineralize on outer layers (called sclerotic dentin, shiny, dark). Need vital pulp.
2. Moderate intensity attack. More intense caries activity. Can cause degeneration and death of odontoblasts and mild pulp inflamation. Pulpal blood supply important limiting factor to recovery.
3. Severe - death of pulp, infection, abscess. Blood supply impaired.

Question 29

Pulp stones

Answer 29

Reparative dentin in pulp, trauma was present and it didn’t know where to build.

Question 30

Sclerotic dentin

Answer 30

Irregular - can’t even find tubules sometimes.

Question 31

Zones of dentin caries

Answer 31

advances w/3 changes

1. Weak organic acids demineralize dentin.
2. Organic material of dentin (collagen) dissolves.
3. Loss of structural integrity.

Question 32

Zone 1

Answer 32

Normal dentin - deepest area in lesion. Has tubules with odontoblastic processes. No bacteria in tubules. Very painful.

Question 33

Zone 2

Answer 33

Affected dentin. Damage to odontoblastic processes. Softer than normal dentin. Large crystals in lumen of dentinal tubules for occluding bacteria. Collagen cross-linking remains (can be repaired). Can be subclassed (sub-transparent, transparent, turbid). If cleaned and sealed off, it can be remineralized. Partial excavation restoration sometimes used.

Question 34

Zone 3

Answer 34

Infected dentin - layer clinician encounters first. Zone of bacteria is marked by widening/distorted dentinal tubules. Little mineral present, collagen is irreversibly denatured.