CAP2-4 Flashcards
Name the 4 types of non-carious tooth surface loss
- Erosion
- Abrasion
- Attrition
- Abfraction
What is tooth erosion caused by?
Acids from food e.g. fruits, fizzy drinks, stomach contents, acid reflux
What is abfraction caused by?
Impact from another object e.g. toothbrush
What is dental attrition?
Tooth surface loss due to tooth on tooth mechanical wear and grinding
Describe the enamel structure
A prism unit made up of a prism core (centre) and a prism sheath (periphery)
Describe the structure of the enamel prism core
Tightly packed hydroxyapatite with little inter-crystalline spaces
Describe the structure of the enamel prism sheath. What activity starts here?
Less well packed crystals with spaces (pores) containing water and organic material, allowing easy diffusion of acid.
Demineralisation starts here
What are the 2 conditions necessary for detection of white spot lesions
- Clean (plaque-free) teeth
2. Dry teeth
Does a mineralised surface appear lighter or darker in a micro-radiograph?
More mineralised - lighter
Less mineralised - darker
Name the 4 lesion zones of enamel caries (starting from the advancing front)
- Translucent zone
- Dark zone
- Body of lesion
- Surface zone
Porosity in Translucent zone?
Few large pores due to the loss of prism periphery
Porosity in Dark zone?
porosity of 5-10% - consists of large and small pores
Porosity in body of lesion?
porosity of 25-50%
Porosity in the surface zone?
porosity of 1-2%
How do arrested caries appear histologically?
Wide and well-developed dark zone
What results in arrested caries?
- Re-mineralisation
- Changes in environment - plaque control, fluoride and altered diet
Name the 3 zones in the ‘zone of established dentine caries’ (from the outermost)
- Zone of Destruction
- Zone of bacterial penetration
- Advancing front of dentine
What are the 3 possible reactionary defence mechanisms to dentinal caries?
- Reactionary Tertiary Dentine - form at the ends of dentinal tubules
- Sclerotic Dentine - blocks tubules
- Reparative Tertiary Dentine - if rapid progression and there is no sclerosis + death of odontoblasts
In which zone is the tubular structure of dentine no longer present?
Zone of destruction
Classify dentinal caries into 2 zones
- Outer, superficial zone
2. Inner, deeper zone
Name 3 differences between the outer, superficial zone and the inner, deeper zone of dentinal caries
- Outer, superficial zone is highly infected with bacteria whereas the inner, deeper zone is minimally infected
- Irreversibly damaged dentine in the outer, superficial zone whereas the dentine in the inner, deeper zone is reversibly attacked
- Proteolytic degradation of collagen matrix in the outer, superficial zone whereas the collagen matrix in the inner, deeper zone has not been severely damaged
What is the critical pH of enamel? What happens beyond that pH?
5.5
Hydroxyapatite starts to dissolve
Bacteria in plaque - factors affecting acid production (x5)
- number of acidogenic bacteria
- types of acid produced
- number of acid-consuming bacteria
- number of base-producing bacteria
- metabolic state of bacteria when food is ingested
Name 3 nutritive alternative sweeteners
- Xylitol
- Mannitol
- Sorbitol
