L3 Aetiology of Dental Caries Flashcards
What are the major consequences of untreated dental caries?
- Bacterial infection of the pulp, pulp inflammation and death
- Inflammation of the periapical tissues (within alveolar bone)
- Infection of the jaw and adjacent tissues e.g. abscess, laryngeal obstruction
What has been the trend in dental caries incidence since the 70s in developed and developing countries?
Developed countries: steady decrease in DMFT.
Developing countries: increase in DMFT (intro of Western diet).
What is acidogenic theory of dental caries aetiology?
Acidogenic theory
- Acid from fermentation of dietary carbohydrates by oral bacteria causes demineralisation of tooth substance
- Subsequent disintegration of the organic matrix
What is proteolytic theory of dental caries aetiology?
Proteolytic theory
- Initial attack is enzymatic destruction of organic matrix of enamel
- Allows greater penetration of enamel by acid, causing demineralisation of enamel
What is proteolysis chelation theory of dental caries aetiology?
Proteolysis chelation theory:
- Products of bacterial metabolism remove calcium ions from mineral phase by chelation, without involvement of acid
What are the requirements for dental caries?
- Bacteria
- Sugar
- Susceptible tooth surface
- Time
What are stagnation areas?
Areas where plaque accumulates, difficult to clean
- Occlusal fissures
- Interproximal space below contact point
- Areas along the gingival margin
What type of bacteria are most commonly assocaited with dental caries, gram positive or negative?
Gram positive
Which bacteria is involved in initiation of almost all carious lesions of enamel?
S. mutans
Which sugars were found to decrease caries incidence when replacing sucrose?
- Fructose group had 32% less new caries than the sucrose
group - Xylitol group had 90% less new caries than control group
Xylitol is a non-fermentible sugar
Which factors related to sugar consumption contribute most to dental caries formation?
- Frequency of sugar exposure
- Amount of sugar consumed
What is the critical pH?
pH 5.5
How does increasing sucrose concentration affect plaque pH?
Increasing sucrose concentration causes plaque to fall to a lower pH and for a longer period of time (more difficult to return above critical pH)
What is the effect of age of dental plaque on acid production?
Older plaque causes a greater fall in pH for a longer period of time when exposed to sucrose.
How many white spot lesions penetrate into dentine after 3/4 years?
Only half of lesions penetrated dentine.
Suggests that progression of carious lesions is not inevitable and the possibility of remineralisation exists.
