| Object: Eight representative target bacteria were extracted from the teeth with combined periodontal-endodontic lesions,and the changes in the number of dental plaque before and after root canal treatment were analyzed to further understand the correlation between pulpal infection and periodontal infection,and to clarify the effect of root canal therapy on the control of periodontal infection in periodontal-endodontic lesions.To provide a theoretical basis for endodontic treatment to improve the prognosis of periodontal inflammation.Methods: The patients with periodontal combined periodontal pulp disease requiring root canal treatment were selected from the stomatology Department of Xinjiang Uygur Autonomous Region People’s Hospital from January 2021 to June 2022.According to the inclusion and exclusion criteria,31 patients(only one affected tooth per patient)were collected,with an average age of 27 to 71 years old.DNA was extracted,8 kinds of target bacterial gene fragments were constructed,recombinant plasmids were constructed and quantitative standards were established.Real-time fluorescence quantitative PCR was used to detect the number of Tannerella forsythia(Tf)、 Porphyromonas gingivalis(Pg)、 Fusobacterium nucleatum(Fn)、 Prevotella intermedia(Pi)、 Treponema denticola(Td)、Digestive streptococcus(Ds)、Enterococcus faecalis(Ef)、Porphyromanus endodontics(Pe).The changes in the number of target bacteria in the periodontal pocket before and after root canal treatment were analyzed to study the effect of root canal treatment on the bacterial spectrum of periodontal combined endodontic lesions.All data were analyzed using SPSS 25.0 software.Results: 1.After the standard preparation of 8 kinds of target bacteria,the plasmids were extracted and sent to Shanghai Sangon for sequencing.The homology analysis with the target fragments showed that:The sequence identity of Ef,Pe,Pg,Pi,Tf,Td,Ds and Fn were 99.5%,100%,100%,99.5%,96.7%,100%,99.4% and 100%,respectively.The linear standard quality plasmid was diluted by 10 times,1/10 times,1/100 times,1/1000 times,1/10000 times and 1/1000000 times to generate the standard curve of various genes,and the eight target bacteria had good linear correlation analysis with the detection CT value.2.The number of bacteria in the root canal was positively correlated with dental plaque,and the number of bacteria in the root canal tissue was lower than that in the dental plaque(P <0.001).8 strains of target bacteria were detected in the root canal and periodontal pockets of 31 teeth before root canal treatment.The total detection rate of each strain was 100%.The proportion of Tannerella forsythia,Prevotella intermedia and Porphyromonas endodontics in dental plaque was 41.64(%),21.72(%)and 20.93(%),respectively.Porphyromonas endodontalis(41.64 %),Treponema denticulosa(25.16 %),and Streptococcus pepticus(14.04 %)were the most common bacteria in the root canal.3.8 kinds of target bacteria could also be detected in the periodontal pocket before and after root canal treatment,and the detection rate of 8 kinds of target bacteria was 100%.Among them,the number of Pe,Pg and Pi bacteria was the most significant,respectively(t=2.187,P=0.044;t=2.893,P=0.011;t=2.164,P=0.045),and the differences were statistically significant(P <0.001).The number of bacteria in the periodontal pocket after root canal treatment was significantly lower than that before root canal treatment,and the difference was statistically significant(P<0.05).Conclusion: In combined periodontal-endodontic lesions of periodontal origin,the infection of suspected periodontal pathogens is the main cause.After perfect root canal treatment,the root canal system is tightly sealed,which reduces the mutual communication with the periodontal and pulp tissues,so that the periodontal inflammation can be effectively controlled. |
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