Long‐term changes in microbiology and clinical periodontal variables after completion of fixed orthodontic appliances

Structured Abstract Objectives The aim of this prospective study was to monitor patients' microbiological and clinical periodontal parameters prior and up to 2 years after orthodontic treatment. Material and Methods Twenty-four adolescents were treated with brackets. Fourteen of them received bands on upper first molars for extra-oral force application before bonding brackets to the remaining teeth. Microbiology, periodontal probing depth, bleeding on probing (BOP), and gingival crevicular fluid (GCF) flow were assessed at baseline (T1), bracket removal (T2), and 2 years post-treatment (T3). A statistical comparison was made over time and between bands and brackets. Results A significant increase from T1 to T2 and a decrease from T2 to T3 in pathogenicity of plaque were noted. No significant difference was observed concerning supragingival colony-forming units (CFU) ratio (aerobe/anaerobe) between T3 and T1. However, the subgingival CFU ratio (aerobe/anaerobe) at T3 did significantly differ from the ratio at T1. Periodontal probing depth, BOP and GCF flow showed a significant increase between T1 and T2 and a reduction between T2 and T3, resulting in the absence of significant differences between T3 and T1, except for BOP at banded sites. Conclusion Placement of fixed appliances has an impact on periodontal parameters. The results showed that not all parameters were normalized at T3, indicating that the changes are only partially reversible.