Dental caries develop due to an increase in strongly acidogenic
and aciduric Gram-positive bacteria while common forms of periodontal
disease are linked to anaerobic Gram-negative bacteria in
subgingival plaque.While caries and periodontitis are bacterial diseases,
Wade (2013) makes the case that they are not infectious
diseases sensu stricto because they result from a complex interaction
between the commensal microbiota, host susceptibility and
environmental factors such as diet and smoking. Periodontitis, in
particular, appears to result from an inappropriate inflammatory
reaction to the normal microbiota, exacerbated by the presence of
some disease-associated bacterial species.