Effects of orthodontic treatment on porphyromonas gingivalis, gingipains and gingival inflammation

Purpose: To assess the effects of orthodontic treatment on the changes of Porphyromonas gingivalis (P.g) and gingipains as well as gingival inflammation. Materials and methods: A total of 105 patients who had healthy gingivae and were treated as research subjects, the gingival crevicular fluid of whom was all collected before treatment and in the 1st, 2nd, 3rd, and 6th months after wearing an appliance. Then, the 16S ribosomal deoxyribonucleic acid (rDNA) polymerase chain reaction (PCR) technique was employed to detect the levels of P.g, Lys-gingipain (Kgp) and Arg-gingipain (Rgp) in the specimens. It was followed by a statistical analysis of the data via the SPSS 23.0 software package. Results: In P.g detection, the 16S rDNA PCR technique presented specific advantages and high sensitivity. The positive detection rate of P.g in the 1st, 2nd and 3rd month of treatment (p < .05), that of Kgp in P.g-positive patients in the 2nd and 3rd months of treatment (p < .05), and that of Rgp in P.g-positive patients in the 2nd and 3rd months of treatment (p < .05) were higher than the pre-treatment results. Compared with gingival index (GI)-0 patients, GI-1 patients exhibited higher positive detection rates of P.g and Kgp and Rgp, which were further found to be positively correlated with the treatment duration and GI (p < .05). Conclusion: In the early stage of orthodontic treatment, the levels of P.g, Kgp and Rgp rise after wearing the appliance, inducing gingival inflammation.