Histopathology of Caries Flashcards
(26 cards)
What are Dental Caries?
- Bacterial disease of the calcified dental tissues
- Characterised by the demineralisation of the inorganic an destruction of the organic substance
Classifications of Dental Caries: What are the different sites of attack?
- Pit and fissure caries
- Smooth surface caries
- Cemental or root caries
- Recurrent caries
What are Pit & Fissure Caries?
- On the occlusal surfaces of molars and premolars
- Buccal and lingual surfaces of molars
- Lingual surfaces of incisors
What are Smooth surface caries?
Approximal surfaces typically:
- Below contact points
- Progression leads to cavitation
Gingival 3rd of buccal and labial surfaces:
- Similar to proximal caries
- Almost always produce wide open cavity
What are Cemental (root) Caries?
- The root surface exposed to oral environment
- Periodontal disease
- Causes softened root surface
- Shallow cavities with ill defined boundaries
- Subsurface demineralisation may reach the dentine
What are Recurrent caries?
- Occur around the margin or at the base of a previously existing restoration
What are the Classifications of Dental Caries based on the rate of attack?
- Rampant (Acute) caries
- Slow progressive (chronic) caries
- Arrested caries
What are Rampant/Acute Caries?
- Rapidly progressing caries
- Many or all of the erupted teeth
(kids + bottle milk) - Rapid coronal destruction
- Rapid involvement of the pulp
What are Slowly Progressive (Chronic) Caries?
- Slow progression
- Late pulp involvement
- Common in adults
- Reaction from the pulp (tertiary dentine - sclerosis & reactionary)
What are Arrested Caries?
- Caries of enamel or dentine or root caies that becomes static and shows no tendency for further progression
- BASICALLY - STOP PROGRESSING
Arrested Caries and Enamel: What effect might the removal adjacent teeth have on approximal lesions?
- They can become arrested
Arrested Caries and Dentine: What happens to the caries if Tertiary dentine is produced?
- Lesions with early tertiary dentine (sclerosis) limit inward spread of caries
- They appear deeply stained brown-blackish colour
Histopathology: What’s the appearance of Early Lesions (White Spot Lesion)?
- Cone shaped with the base on the enamel surface (top facing inwards)
- Apex pointing towards the amelodentinal junction
- Different zones reflecting different degrees of demineralisation
What are the 4 zones within Enamel Caries?
- Translucent Zone
- Dark Zone
- Body of the lesion
- Surface Zone
What is the Translucent Zone?
- Advancing edge of the lesion moving towards the amelodentinal junction
- More porous than normal enamel
- Large pores
Could be partially or totally missing
What is the Dark Zone?
- 2-4% of volume of pores
- Larger and smaller pores than translucent zone
- Remineralisation due to precipitation of minerals lost from Translucent zone
- Narrow in rapidly advancing lesions
- Wider in slow lesions with more remineralisation
What’s the body of the lesion?
- 5-25% of pore volume
- Larger crystals than normal enamel
- More prominent Striae of Retzius
What’s the surface zone?
- Highly mineralised zone with minerals coming from the plaque and from the demineralised deeper layers
- Little change in early lesion
What’s the Histopathogenesis of Enamel Caries?
- Subsurface translucent zone
- Enlarges and a dark zone develops in the centre
- Body of the lesion forms in the centre of the dark zone (hite spot)
- When reaching the dentinoenamel junction, caries spread laterally undermining adjacent enamel (bluish)
- After a critial stage, enamel breaks forming a cavity
What are the characteristics of Fissure Caries?
- Caries start to form in the wall of the fissure
- Caries spread outwards to adjacent enamel and downwards towards dentine
- The lesions meet at the base of the fissure
- Cone shaped lesion with a base towards the dentinoenamel junction
- Larger area of involved dentine
What are the characteristics of Dentine Caries?
- Living tissue is capable of responding to carious attacks
- High organic content that might be destroyed
- Pulpal reaction before the lesion reaches the dentine
- Demineralisation occurs before the bacterial front
- Organic matrix break down by bacterial invasion
Dentine Caries: What are the 4 Zones? (1)
Zone of Sclerosis:
- Translucent zone
- Beneath and at the sides of the lesion
- Broader beneath the lesion
- Reaction of odontoblasts to caries
- Higher mineral content = acceleration of peritubular dentine formation & calcification of the odontoblastic process
Dentine Caries: What are the 4 Zones? (1b)
Zone of Sclerosis:
- Dead tracts (dead tracts of fish)
- Death of Odontoblasts
- Air filled (appear black)
- Ready access to the pulp
- Pulpal cells occlude the tracts with hyaline calcified material
Dentine Caries: What are the 4 Zones? (2)
Zone of Demineralisation:
- Intertubular dentine is affected by an acid wave
- Acid diffuses ahead of the bacteria
- Soft dentine and sterile
- Might become stained yellow to other bacterial products
