Study On The Colonization Of Porphyromonas Gingivalis In The Root Canal Of Periapical Periodontitis Patients

Objective:SYBR GREEN real-time quantitative PCR was used to detect the amount of P.gingivalis in the root canal of patients with periapical periodontitis,and restriction fragment length polymorphism analysis was used to determine the kgp genotype.This experiment explores the relationship between the number of P.gingivalis and clinical symptoms,and the relationship between P.gingivalis kgp genotype and clinical symptoms in the root canal of patients with periapical periodontitis,so as to explore the colonization of P.gingivalis in patients with periapical periodontitis in the root canal.Methods: The article included three parts Part1:We cultured P.gingivalis standard strains,extracted bacterial genomic DNA,amplified the target gene of P.gingivalis by PCR,and ligated the target fragment to the p MD18-T vector for plasmid digestion and sequencing verification.Part2:The bacterial genomic DNA was extracted from the root canal of 43 patients with periapical periodontitis.SYBR Green real-time quantitative PCR was used to detect the number of P.gingivalis in the samples,and the relationship between the detection rate and detection amount of P.gingivalis and the clinical symptoms of periapical periodontitis patients.Part3:PCR was used to amplify the fragment encoding the catalytic domain of kgp,and the restriction enzyme Mse? was used to segment the catalytic domain of kgp,so as to determine the genotype of kgp and compare the relationship between different genotypes of kgp and clinical symptoms of periapical periodontitis patients.Results:1.The recombinant plasmid containing P.gingivalis arg-ginggain single copy gene was successfully constructed,and the real-time fluorescent quantitative PCR standard was obtained.2.The detection rate of P.gingivalis in the pain group and the swelling group was higher than that in the non-pain group and the non-swelling group,but there was no statistical difference(P>0.05).There was no significant difference in the detection rate of P.gingivalis between the percussion pain group and the non-percussion pain group,the fistula group(no pyorrhea)and the non-fistula group(P>0.05).Correlation analysis showed that the detection rate of P.gingivalis had no correlation with the pain,percussion pain,fistula(no pyorrhea)and swelling of periapical periodontitis.3.There was no significant difference in the detection amount of P.gingivalis in the pain group and the non-pain group,the percussion pain group and the non-percussion pain group,the fistula group(no pyorrhea)and the non-fistula group,and the swelling group and the non-swelling group(P> 0.05).4.The distribution of kgp genotypes in the pain group and the non-pain group were different.Among them,P.gingivalis in the pain group was mainly kgp ?,and the difference was statistically significant(P<0.05).There was no significant difference in the distribution of kgp genotypes in the percussion pain group and the non-percussion pain group,the fistula group(no pyorrhea)and the non-fistula tract group,and the swelling group and non-swelling group(P> 0.05).Conclusion:1.Real time quantitative PCR can be used for quantitative detection of pathogenic microorganisms of pulp and periapical diseases.2.There was no significant correlation between the detection rate and amount of P.gingivalis and the clinical symptoms of patients with periapical periodontitis.3.There is polymorphism of P.gingivalis kgp genotypes in the root canal of periapical periodontitis patients,and P.gingivalis in the pain group is mainly kgp ?.