Journal of Dental Medicine

Background and Aim: A single nucleotide polymorphism at codon 72 of the p53 gene alters the p53 protein structure and affects its activity. This polymorphism depends on geographic regions and race. Also its association with some cancers has been reported. The aim of this study was to investigate this polymorphism in well differentiated oral SCC and normal population in the city of Isfahan.

Materials and Methods: In this case-control study, 20 paraffin blocks of non metastatic and well differentiated oral SCC were selected from the archive of oral pathology department of dental school between 2001 and 2005. 20 whole blood samples from normal people were considered as control group. After DNA extraction, p53 codon 72 polymorphism was determined by polymerase chain reaction (PCR) technique using specific primers of Arg and Pro and agarose gel electrophoresis. Data were analyzed by Fisher's exact test with p<0.05 as the level of significance.

Results: The prevalence of Arg/Arg , Arg/Pro and Pro/Pro genotypes in case group were 45%,45% and 10% respectively compared to 45%,50% and 5% in controls. There was no statistical significant difference in p53 codon 72 genotypes distribution between case and control groups.

Conclusion: Based on the results of this study, p53 polymorphism could not be considered as a genetic predisposing factor for oral SCC development in Isfahan.

Background and Aims: Periodontitis is one of the most common oral diseases with the various incidence rates in different populations. A number of bacteria are considered as the major etiologic agents of periodontitis. The aim of the present study was to determine the prevalence of periodontopathogen bacteria in patients using both PCR and culture techniques.
Materials and Methods: In this study, one-hundred patients (including 62 females and 38 males with an average age of 49±11.5 years) with adult periodontitis referred to periodontics department of School of Dentistry/Tehran University of Medical Sciences were investigated. The samples were taken and sent immediately to the laboratory for culture and molecular evaluation. The PCR was performed using specific primers and the statistical analysis of data was performed using SPSS statistic software and McNemar test.
Results: The results demonstrated that the total detection rate in culture method was 64%. The rate of Aggregatibacter actinomycetemcomitans (Aa) was 28% which was significantly higher than that of Porphyromonas gingivalis (Pg) (6%) and Prevotella intermedia (Pi) (3%). 27% of cases showed mixed bacterial growth. 65% of patients were positive using molecular method. The rate of Aa (30%) was significantly higher than that of Pg (7%) and Pi (5%). The mixed PCR positive rate containing of Aa, Pg and Pi was (23%).
Conclusion: In this study, it was found that most of the bacteria isolated using culture and molecular methods were Aa, Pg and Pi, respectively. Although the detection frequencies of both techniques were similar, the specificity, sensitivity and bacterial detection speed of the PCR technique is obviously higher. Therefore, the use of molecular techniques is strongly recommended. However, both techniques seem to be suitable for microbiological diagnostics.