# Effects of removable clear dental aligners on the composition of the oral microbiome

## TL;DR

This study examines how clear dental aligners affect the oral microbiome and finds minimal impact on its overall composition.

## Contribution

The study provides new empirical evidence on the stability of the oral microbiome during clear aligner treatment.

## Key findings

- Clear aligners did not significantly alter the overall composition of the oral microbiome.
- Microbiome stability was observed in saliva, subgingival, and supragingival samples during treatment.
- Some species-specific changes were detected but had small effect sizes.

## Abstract

Proper tooth alignment is important for oral and periodontal health, allowing better hygiene and reducing plaque build-up. While traditional braces are effective, clear aligners offer an aesthetic advantage and are also thought to promote better oral hygiene. However, their specific impact on the oral microbiome is not yet fully understood. This longitudinal study used 16S amplicon sequencing to study the oral microbiome (from saliva, subgingival, and supragingival samples) of 11 patients undergoing clear aligner treatment. Samples were collected at three time points: before treatment and at 3 and 6 months during therapy. Our results revealed large differences between the microbiomes of different oral sites but no significant overall changes in the oral microbiome composition due to orthodontic treatment. While some species-specific changes were observed, their effect sizes were very small. Although these results should be confirmed in a larger and more diverse cohort, they suggest that the treatment had a small or negligible impact. Given the observed stability of the oral microbiome in all three studied niches throughout the treatment and the known benefits to oral hygiene, clear aligners may present a favorable therapeutic alternative compared to fixed appliances.

•The study revealed large differences in the composition of the microbiome between the different oral locations (saliva, subgingival and supragingival), although treatment with clear aligners did not significantly alter this overall composition.•The stability of the oral microbiome during treatment with clear aligners, together with their hygienic advantages, positions clear aligners as favorable treatment options over fixed appliances.

The study revealed large differences in the composition of the microbiome between the different oral locations (saliva, subgingival and supragingival), although treatment with clear aligners did not significantly alter this overall composition.

The stability of the oral microbiome during treatment with clear aligners, together with their hygienic advantages, positions clear aligners as favorable treatment options over fixed appliances.