Objective: To investigate the effects of porphyromonas gingivalis (PG) infection on periodontal indexes, nod like receptor protein-3 (NLRP-3) and T-helper cell 17 (Th17) / T-regulatory cell (Treg) balance in patients with chronic periodontitis (CP). Methods: 106 patients with chronic periodontitis who underwent tooth extraction in our hospital from June 2018 to November 2021 were selected as CP Group, they were divided into infection group and non-infection group according to whether they were infected with PG. 63 healthy periodontal patients who treated in our hospital due to impacted teeth and misplaced teeth were selected as the control group. The probing depth (PD), plaque index (PLI), bleeding index (BI), attachment loss (AL) of all objects were recorded,the infection rate of PG was detected by polymerase chain reaction (PCR), the expression of NLRP-3 mRNA, apoptosis-associated speck-like protein containing a CARD (ASC) mRNA and caspase-1 mRNA in periodontal ligament were detected by RT-PCR, the levels of Th17 and Terg in peripheral blood were detected by FACScalibur flow cytometry and Th17 / Treg was calculated, the levels of detection indexes in the two groups were compared. Results: The positive rate of PG infection in the control group was 17.46%, which was lower than 79.25% in the CP Group, the difference between the two groups was statistically significant (P<0.05). The levels of PD, PLI, BI, Al in the infection group were higher than those in the non-infection group, the differences were statistically significant (P<0.05). The expressions of NLRP-3 mRNA, ASC mRNA, Caspase-1 mRNA in the infection group were higher than those in the non-infection group, the differences were statistically significant (P<0.05). The levels of Th17 cells and Th17 / Treg in peripheral blood in the infection group were higher than those in the non-infection group, and the level of Treg in the infection group was lower than that in the non-infection group, the differences were statistically significant (P < 0.05). Conclusion: Most patients with CP have PG infection, PG infection has a significant impact on periodontal health, inflammation and immunity of patients with CP. |