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CLINICALFEATURE
susceptibility or for gingivitis /periodontitis 17, 18 . With regard to
caries saliva samples can be used to establish the numbers
of Streptococcus mutans and Lactobacillus species – the two
major caries associated pathogens.
In order to detect caries associated flora, paraffin wax
stimulated whole saliva samples are collected and a dip slide
containing the selective growth medium (which permits the
growth of only the specific organism) is dipped into the
collected saliva. Afterwards the slide is incubated within the
container at 37 º C for upto 24 hrs and the resultant colonies of
the putative pathogen is assessed in a semi-quantitative
manner. In general the approximate figures for the cariogenic
flora are:
• High caries activity > 10 6 /mL S mutans and/or 105m/L
lactobacillus spp
• Low caries activity : < 10 5 /mL S mutans and/or 104m/L
lactobacillus spp
The presence of high salivary levels of S mutans or
lactobacilli does not necessarily mean that the patient has an
increased risk of developing dental caries, as it is a disease
of multifactorial aetiology 19 . Other factors such as the diet,
buffering capacity of saliva, fluoride content of enamel and
degree of oral hygiene should also be considered. Although
this particular test is at best a generalized approximation of
the caries risk it could be utilized to identify patients who have
unusually high numbers of potential pathogens, so that these
data can be taken into account when integrating all the
factors that may contribute to carious process in an individual
patient. In addition, the test could be utilized to monitor the
efficacy of caries prevention techniques such as dietary and
oral hygiene advice and the use of antimicrobial agents such
as chlorhexidine 20 .
Due to the foregoing reasons salivary-based tests for
monitoring plaque-related infections can not be construed as
truly diagnostic, rather they are harbingers of a patient’s risk
potential for disease and the consequent need for preventive
measures. This approach has proven successful as a public
health, preventive measure especially in Scandinavian
countries for many decades 21 .
With regard to periodontal disease and the detection of major
periodontopathogenic bacteria salivary diagnostics have
proven less successful. Tests are however, now available for
chair-side assessment of Porphymonas gingivalis, a
pathogen closely associated with periodontal disease. Other
salivary markers that have been studied as potential
diagnostic tools for periodontal disease include proteins of
host origin such as enzymes and immunoglobulins, host cells,
hormones (cortisol), bacterial metabolites and volatile
compounds.
Of these, host-derived enzymes and other inflammatory
mediators originating from the gingival crevice appear to hold
the greatest promise as salivary diagnostic tests for
periodontal disease both on an individual basis or on a
community wide assessment of risk for periodontal disease.
The recent exciting developments on the potential role of
periodontal disease as a risk factor for cardiovascular and
cerebrovascular diseases 22 and the incidence of pre-term lowbirth-weight
babies 23 bring new impetus to this aspect of
salivary diagnostics.
It is now well recognized that Helicobacter pylori are the
causative agents of a significant proportion of gastritis and
duodenal ulcers (peptic ulcer disease) in humans and, it may
also play a role in gastric cancer 24 . Studies have also shown
that dental plaque biofilms may act as a reservoir of H pylori
in some of these individuals. Hence attempts have been
made to use saliva as a diagnostic aid for peptic ulcer
disease. A nested PCR assay is now available to detect H.
pylori DNA in saliva and confirm the presence of H. pylori
infection in patients 25 . Other immunologic studies indicate that
saliva may also be used for predicting risk for gastric
adenocarcinoma 26 .
Saliva from patients with a variety of other disorder including
shigellosis, pigeon breeders disease and Lyme disease have
been evaluated for the presence of specific antibodies, with
mixed results 27 . But with the increased sensitivity of tests and
advancing technology it is likely that saliva would be used as
an important diagnostic fluid for such disease entities.
Auto-immune Disorders
When body defenses turn against itself as seen in many
autoimmune disorders, diseases such as Sjögren’s syndrome
may ensue. The latter is a chronic, illness characterized by
20 Dental Asia • May / June 2008