Microbiome Changes In Orthodontic Patients With Brackets Versus Clear Aligners

Objectives: Corrective orthodontic movement is typically accomplished with fixed appliances (FA) or clear aligners (CA). Since little is known about it and how these two different appliances effect the oral microbiome, to our best knowledge, we for the first time performed a longitudinal evaluation of the oral microbiome and clinical parameters in patients treated with FA compared to CA.
Methods: 15 patients each participated in the FA and CA groups. Clinical parameters including Plaque Index (PI) and Gingival Index (GI) were determined and oral biofilms were collected from central incisors, first premolars, and the most recently worn CA at the following time points: prior to treatment, and at 1, 3, and 6 months after receiving the appliances. DNA was extracted and subjected to next generation 16s rRNA gene sequencing.

Results: Both PI and GI increased significantly more over time in the FA group compared to the CA group. This was more pronounced in the posterior teeth. Microbiome analysis revealed a distinct shift in the taxonomic composition of the tooth-associated biofilm already within the first month after beginning treatment. . The community level between applicances are under analysis now. The CA trays in contrast harbored a unique microbial community with greatly reduced diversity that formed a distinct cluster upon Beta-diversity analysis.

Conclusions: Clinical parameters during the 6 months study period increase significantly more in FA compared to CA patients. The largest shift in biofilm composition occurs within the first month after starting treatment and the biofilms colonizing CA trays are significantly different from the tooth-associated ones.