Cariology (Sharples) Midterm Flashcards
Enamel (hydroxyapatite) pH critical level
5.5
Dentin pH critical level
6.2
Enamel (hydroxyfluorapitite) critical pH level
4.5
A caries lesion in any surface of the anatomical tooth crown
Coronal Caries
A caries lesion not adjacent to an existing restoration or crown
Primary Caries
Enamel Composition
90-92% inorganic (HA- hydroxyapatite)
4-12% Water
1-2% protein
Enamel origin
Epithelial origin, built by ameloblasts which die after deposition
Enamel at cervical and incisal/occlusal areas; harder to cleave
Gnarled Enamel
Structural properties depend on direction force is applied (ex: enamel)
Anisotropic
Same structural properties regardless of force direction (ex: composite)
Isotropic
Dentin composition
50% inorganic (HA; 75% wt)
25% collagen (20% wt)
25% water (5% wt)
Dentin development
Mesenchymal origin; built by odontoblasts which remain in pulp
Dentinal Tubule function
Allow fluid movement and ion flow
->Remineralization, apposition of peritubular dentin, pain perception
Dentin Properties
20% less hard than enamel
Higher tensile strength, lower stiffness
Isotropic
Unmineralized zone of dentin immediately superior to cell bodies of odontoblasts
Predentin
Dentin that forms up to 3 yrs after eruption
Primary Dentin
Dentin in which direction changes and deposition slows
Secondary Dentin
Formed dentin in response to stimulus (bacteria); often forms into pulp
Reparative Dentin
Calcification in dentin tubules due to injury/increasing age
Sclerotic Dentin
Cementum (Periodontium) composition
45-50% inorganic (HA)
50-55% organic (water)
5-10% mineral
(Highest fluoride content of all mineralized tissue)
Sudden dryness in mouth (from radiation, medication, etc.)
Xerostomia
Diet effect on caries process
Sucrose -> promotes highly acidogenic bacteria growth
Acidic food -> caries
Hypocalcified Caries
Developmental white spot
Same wet or dry
Do not restore unless for esthetics
Non-cavitated Caries (White Spot lesion)
- Demineralized but not cavitated
- Disappear when wet
- Don’t restore
- Proximal lesions in enamel
Active Caries
- Surface disturbed/missing
- Soft, chalky surface found with explorer tip
- Proximal lesions into dentin
- Can’t remineralize, must restore
Inactive Caries
- Calcium and phosphate in saliva help remineralize
- Remineralized more resistant, looks discolored (brown/black)
- Don’t restore unless for esthetics
