الفهرس 
REVIEW OF LITERATURE
Radiographic assessmentOnly 14 pages are availabe for public view
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Abstract
Periodontitis is an inflammatory disease involving the destruction of both soft and hard tissue in the periodontal region. Many factors can influence its etiology, but specific Gram-negative anerobic bacterial species are required for its development in subgingival plaque as; P. gingivalis, T. forsythia, T. denticola, P. intermedia, and A.a.
For the identification of periodontal microorganisms, different techniques have been used such as culture technique, DNA-DNA hybridization, immunological and immunoenzymatic analyses. Nonetheless, these techniques display different limitations. However, real time PCR method is a most precise, efficient, and rapid method for the detection, identification, and quantification of periodontal microorganisms.
The purpose of the present study was to investigate the bacterial levels of P. gingivalis, T. forsythia, T. denticola, P. intermedia, and A.a in subgingival plaque in patients with grade B periodontitis and healthy individuals in a group of Egyptian and Yemeni participants.
The present study was conducted on (80) participants, (40) participants were from the Egyptian population, and the other (40) participants were from the Yemeni population. The Egyptian participants were divided into two groups, (20) participants with periodontitis and (20) healthy controls. The Yemeni participants were divided into two groups, (20) participants with periodontitis and (20) healthy controls.
The following clinical parameters were recorded for each participant; PI, GI, BOP, PD, CAL and radiographic examination was done for all participants. Bacterial samples were collected from the deepest periodontal pocket in the Periodontitis group of participants. Whereas the mesiobuccal side of the permanent maxillary left first molar was chosen to collect the microbial sample in the Control group. A sterile paper point was used for bacterial sample collection.
DNA from all subgingival clinical samples was isolated using DNA/RNA extraction kit (PREP DNA/RNA EXTRACTION KIT/DNA TECNOLOGY RUSSIA). PCR mixture solution was used with real time PCR machine (PARODONT REAL-TIME PCR DETECTION KIT/DNA TECNOLOGY RUSSIA).
The results of the present study showed that overall, the bacterial counts of the five periodontal pathogens were high in the periodontitis group compared to the healthy control group in both populations.
The present study showed a high detection frequency of periodontopathic bacteria; P. gingivalis, T. forsythia, T. denticola, P. intermedia, and A. actinomycetemcomitans in periodontitis participants in both populations. The differences in the bacterial load between the two populations were statistically non-significant except for the T. denticola, which was significantly more prevalent in the periodontitis participants in the Egyptian population. T. forsythia was the most frequently detected species among periodontitis participants in both populations which may reflect its role in periodontal destruction in the two populations.