Longitudinal changes in microbiology and clinical periodontal variables after placement of fixed orthodontic...

In the past few decades, more patients have been treated orthodontically, but no longitudinal study has compared orthodontic bands and brackets microbiologically and clinically.

This longitudinal trial (split-mouth design) included 24 patients. Microbiology (sub- and supragingival), probing depth (PD), bleeding on probing (BOP), and gingival crevicular fluid flow (GCF) were assessed at baseline (band placement) and at weeks 18 (bracket bonding) 20, 24, and 36. A statistical comparison was made over time and among the banded, bonded, and control sites.

The aerobe/anaerobe ratio of sub- and supragingival colony forming units decreased significantly (relatively more anaerobes) over the study period for the banded and bonded sites (P <0.001). This decrease was accompanied by significant elevations in PD, BOP, and GCF. These changes occurred faster after bonding compared to banding. No significant changes were observed 18 weeks after banding with the exception of increased PD (P <0.001). At week 36, all microbial and clinical variables at the bonded site had changed significantly in the negative direction (P <0.001) compared to week 18. The control sites did not show any significant changes over time, indicating that the effects were localized.

The placement of fixed orthodontic appliances had a significant impact on microbial and clinical variables. The changes occurred faster at the bonded sites compared to the banded sites, probably because wire insertion caused difficulties in approximal cleaning. Over the long term, banding did not lead to more adverse microbial and periodontal effects than bonding.