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All subjects must present with the same symptoms
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Causative organism must be isolated in pure culture
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When inoculated into a 2nd host, it must produce the same symptoms
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Identical pure culture must be obtained from second host
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> No overt pathogen - mostly mixed infections
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> More than 700 identified oral species
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> Not all members of biofilm community are cultivable
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> Presence may be as a result rather than cause of disease
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> Sites don't appear to be actively progressing at all times
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> Different sites in mouth may break down as a result of different species
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> Strains of putative pathogens may vary in virulence
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> Some strains may harbour bateriophages or plasmids that confer virulence properties
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Overgrowth of indigenous microbiota
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Same organisms observed in health and disease
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Shifts in microbial proportions rather than specific pathogens
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Any plaque biofilm can cause disease
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More sophisticated studies demonstrated:
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> Improved cultural and sampling methods
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> Composition of plaque biofilm differs both inter-orally and intra-orally
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> Increase at a sight of infection
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> Decrease in health or following treatment
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> Qualitative changes in plaque biofilm
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Exogenous pathogens and not endogenous microbiota caused disease
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Fails to explain:
> Mode of transmission
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> Acquisition
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> Means of colonization
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> Effect of treatment on indigenous species
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Opportunistic endogenous infection
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Ecological shift from predominatly G+ cocci to G- rods/cocci-bacilli
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Any bacterial species may be pathogenic
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Ecological changes in environment dictate virulence mechanisms
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Disease prevented by elimination or interruption of ecological succession
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Most common:
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1. Dental caries (supragingival plaque)
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2. Periodontal disease (subgingival plaque)
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1) Tooth worm:
5000BC, 1803 - Diagrams and 1825- Case histories
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2) Humoral Theory:
Blood, phlegm, black bile, yellow bile - Imbalance= disease
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3) Chemical Theory:
Fermentation of food remains
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4) Parasitic Theory:
Decomposition resulting from action of organisms in the mouth
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2 stage process:
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i) decalcification of enamel resulting in destruction of dentin
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ii) dissolution of softened residue of enamel and dentin
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Schutz and Martin (1955)
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Simultaneous attack on organic and inorganic compounds of tooth
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