Dental Caries: History, theories, and definitions Flashcards
What are the exogenous theories of dental caries?
Worm theory
Chemical (acid) theory
Parasitic (septic) theory
What are the endogenous theories of dental caries?
Humoral theory
Vital theory
What are the non-exogenous AND non-endogenous theories of dental caries?
The acidogenic theory
The proteolytic theory
Proteolysis Chelation theory
Sucrose Chelation theory
What are the current concepts of caries aetiology?
Demineralisation and remineralisation
What is the worm theory of dental caries?
Dental caries are the result of a “worm that drunk blood of the teeth and fed
on the roots of the jaws”
What is the chemical theory of tooth destruction?
During the 17th and 18th centuries the theory was that teeth were destroyed by acids formed in the oral cavity.
In this theory it was believed that putrefaction of protein led to formation of ammonia which was subsequently oxidised to nitric acid. In other words, fermentation was considered a non-vital process.
What is the humoral theory of tooth destruction?
A persons physical and mental constitution was determined by the relative
proportions of the four elemental fluids of the body which correspond to the four humors,
What is the proteolytic theory of tooth decay?
Caries-like lesions are initiated by proteolytic activity at a slightly alkaline pH and considered that the process involved depolymerisation and liquefaction of the organic matrix of enamel.
Microorganisms invade the organic pathways (lamellae) of enamel and
initiate caries by proteolytic action. Subsequently the organic salts are
dissolved by acidogenic bacteria
What is the acidogenic theory of tooth decay?
Dental decay is a chemo-parasitic process consisting of two stages:
- i) Decalcification (preliminary step)
- ii) Dissolution(subsequent step)
What did the acidogenic theory of tooth decay show?
Showed that the degradation of carbohydrate containing food resulted in acid formation and tooth tissue destruction
Demonstrated this process invitro, with isolated oral bacteria and extracted teeth
What were miller’s conclusions in the acidogenic theory of tooth decay?
Dental caries are caused by multiple species of oral bacteria
No specific bacteria was implicated
Traditional non-specific plaque hypothesis
Proper prevention is therefore needed to remove or minimise multiple bacterial species
What were the limitations of the acidogenic theory?
Unable to explain site-specificity (esp.smooth surface)
Does not determine specific bacterial aetiology
Does not explain why some populations are caries free
Cannot explain arrested caries
What is the specific plaque hypothesis?
In the 1970s, culture-based techniques and microscopy allowed discrimination of
specific bacterial species
It was noticed that the antibiotic kanamycin was particularly effective against cariogenic species such as oral streptococci and reduced caries formation
Removing cariogenic bacteria from the oral cavity using antibiotics could prevent caries
What are the limitations of the specific plaque hypothesis?
Use of kanamycin resulted in overall reduction of caries but at some surfaces the caries rate increased.
Cariogenic bacteria were not eliminated after treatment.
How was the specific plaque hypothesis updated?
To the non-specific plaque hypothesis. Specific pathogens from the SPH were indigenous bacteria and sometimes common bacteria in health.
During this time most researchers seemed to agree that gingivitis was a non-specific inflammatory reaction to a complex indigenous microbiota.
Some bacteria could be more virulent than others
