Day 3 lecture 2 Flashcards
Know major cariogenic bacteria
Know major cariogenic bacteria
3 sites for caries initiation
Different lesions at different sites.
- Pit and fissures
- Smooth enamel surfaces
- Root surfaces
Pits and fissures
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.
Progression of caries - pits and fissures
Progresses along enamel rods (why it is angular and spreads).
Enamel lesion
Decay in enamel - E1 if less than halfway through. More than halfway = E2. Doesn’t depend on dentin decay.
“Watch”
Don’t cut. What you can do is have flouride treatment, watch diet.
Entering dentin
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.
Deeper into dentin
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
Remineralization
Requires a good vital functioning blood supply in the pulp.
Moving into pulp
Occlusal surface darkens significantly.
Smooth enamel surface
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.
Dentin decay
D1 - first third or so, D2 - rest of the way. Cut on D1 and D2. D2 usually crowned.
Root surfaces
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.
Progression of caries lesions
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.
Xerostomia
Head and neck radiation loses salivary glands.
Enamel Caries histopathology
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.
Enamel caries variety
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.
Hypocalcified enamel
(undercalcified- look white and opaque). Don’t go away when wet. Do not restore unless aesthetic (patient wants it).
White spot lesion
(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.
Cavitated enamel lesion
(active caries). Connection between outside of tooth and dentin. Restoration needed, as original framework is gone. Bigger in mouth than on x-ray
Remineralized enamel lesion
(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.
Kissing lesions
Mesial/distal surfaces of teeth share adjacent lesions.
Cervical burnout
Tooth narrows, doesn’t have as much density.
Enamel caries summary **
Know this slide* - add all
Normal enamel
Hydrated:
Desiccated:
Surface texture:
Surface Hardness:
More pain from
Enamel to dentin. As it goes further into dentin, there is less pain. Little response to pain in Dentin.
Dentinal caries
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.
Pulp-dentin complex react to caries attack
- 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.
- 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.
- Severe - death of pulp, infection, abscess. Blood supply impaired.
Pulp stones
Reparative dentin in pulp, trauma was present and it didn’t know where to build.
Sclerotic dentin
Irregular - can’t even find tubules sometimes.
Zones of dentin caries
advances w/3 changes
- Weak organic acids demineralize dentin.
- Organic material of dentin (collagen) dissolves.
- Loss of structural integrity.
Zone 1
Normal dentin - deepest area in lesion. Has tubules with odontoblastic processes. No bacteria in tubules. Very painful.
Zone 2
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.
Zone 3
Infected dentin - layer clinician encounters first. Zone of bacteria is marked by widening/distorted dentinal tubules. Little mineral present, collagen is irreversibly denatured.
