The Study Of Porphyromonas Gingivalis Pathogenicity Island Gene And Pathogenicity In Gingivitis Patients After Orthodontic Treatment

Objective The gingivitis usually results from a variety of factors in the orthodontic treatment. Previous studies demonstrated that Porphyromonas gingivalis and pathogenicity island-rag genes were closely related with the periodontitis. However, the relationship between the pathogenicity island-rag genes of Porphyromonas gingivalis and gingivitis in orthodontic process was less reported. The purpose of this study was to explore correlation of Porphyromonas gingivalis and gingival inflammation degrees through established multiple PCR, and then analyze its role in occurrence and development of gingivitis during orthodontic treatment.Methods The primers of Porphyromonas gingivalis were designed based on its16S rRNA and pathogenicity island rag genes. Multiple PCR was set up to detect Porphyromonas gingivalis and pathogenicity island genes. The specificity and sensitivity of the PCR were examined by using reference strains. The gingival crevicular fluids of patients with different gingival status in orthodontic treatment were collected. The16S rRNA and pathogenicity island rag genes of Porphyromonas gingivalis were detected. The data from orthodontic and periodontitis patients were compared. The correlation of distribution of rag genes and clinical indicators was analyzed. Results Multiple PCR was established with higher sensitivity and specificity. The results of multiple PCR were consistent with that of general PCR. The distribution of pathogenicity island rag genotypes was different in the high virulence strains and low virulent strains. There was significant positive correlation between the detection rate of P.gingivalis and the gingival index (GI). The detection rate in orthodontics group was higher than the control group, and periodontitis group showed the highest detection rate in the three groups. Significant variance was showed among them (X2=15.918,P<0.01) Pathogenicity island rag genes of P.gingivalis in orthodontics treatment group was significantly higher than the control group, and periodontitis group showed higher detection rate of rag genes than the orthodontics treatment group and control group, there was significant variance among them (X2=22.593,P<0.01). The distribution of four rag genotypes from the overall detection rate was as follows: the detection rate of rag-3type was the highest and followed by rag-4. The rag-1and rag-2type was relatively lower. There was significant difference among them (P<0.05).Conclusion1. Multiple PCR was established with higher sensitivity and specificity.2. The distribution of pathogenicity island rag genotypes was different in the high virulence strains and low virulent strains. 3. Pathogenicity islands rag gene of Porphyromonas gingivalis was closely related with the development of gingivitis in orthodontics treatment.4. The distribution of rag genotypes in Porphyromonas gingivalis was different. P.gingivalis with rag-3and rag-4may be associated with the development of gingivitis in the patients with orthodontics treatment.