| dc.description.abstract | Black-pigmented anaerobic rods, Fusobacterium nucleatum, Actinobacillus
actinomycetemcomitans, Eikenella corrodens, Tannerella forsythensis and
Treponema denticola are putative periodontopathogens indigenous to the
oral cavity, which frequency and proportion in healthy and diseased
periodontal sites may exhibit regional differences. The purpose of this study
was to evaluate, by employing microbiological culture and PCR, the
presence of these microorganisms in periodontal sites of 30 patients with
chronic periodontitis, 30 patients with aggressive periodontitis and 30
subjects with healthy periodontium. The samples were collected with paper
points and transferred to Ringer PRAS solution, under CO2 flux. The material
was homogenized, introduced into an anaerobic chamber and, following
serial 10-fold dilutions up to 10-4, it was cultured onto selective media and
incubated at 37ºC for up to 15 days. Bacterial identification was based on
macroscopic, microscopic and biochemical-physiological characteristics.
Also, part of the clinical specimen was centrifuged and the sediment used
for DNA extraction by the phenol-chloroform method. Specific primers that
targeted the 16S rDNA were employed for PCR amplification. The results of
the microbiological culture have shown associations between P.
intermedia/nigrescens, F. nucleatum, F. varium and chronic periodontitis,
and between P. intermedia/nigrescens, A. actinomycetemcomitans and
aggressive periodontitis. The PCR results have indicated that P. intermedia,
P. nigrescens, Fusobacterium spp., T. forsythensis and T. denticola were
statistically associated to the chronic and the aggressive forms of
periodontitis, whereas E. corrodens was shown to be associated only to
chronic periodontitis. PCR has been shown to be more sensitive for the
detection of most of the investigated microorganisms. The antagonistic or
synergistic associations observed among the bacterial samples isolated from
patients with aggressive periodontitis, differ from those found in patients
with chronic periodontitis, which reinforces the importance of those
associations in periodontal disease expression. | |
