Effect of an enzyme-containing mouthwash on the dental biofilm and salivary microbiome in patients with fixed orthodontic appliances: a randomized placebo-controlled pilot trial

Abstract

Background: Mouthwashes containing oral antiseptics or enzymes are suggested suitable for controlling biofilm accumulation in patients with fixed appliances and thereby limiting unwanted side effects during the orthodontic treatment.

Objectives: To evaluate the effect of an enzyme-based mouthwash on the amount of dental biofilm and the composition of the salivary microbiome in patients undergoing treatment with fixed orthodontic appliances.

Trial design: Randomized double-blind placebo-controlled trial.

Material and methods: In total, 35 young adolescents (14-18 years) under treatment with fixed appliances were consecutively enrolled and randomly allocated to an experimental or a placebo group by opening a computer-generated numbered envelope. The subjects were instructed to rinse twice daily during an intervention period of 8 days with experimental mouthwash or placebo without active enzymes. Unstimulated whole saliva samples were collected at baseline and after 8 days. The participants and examiner were blinded for the allocation. The primary outcome was the Orthodontic Plaque Index (OPI) and the secondary was the composition of the salivary microbiome.

Results: In total, 28 adolescents (21 females and 7 males) completed the trial and there were no differences in age, clinical, or microbial findings between the test (n = 14) and the placebo group (n = 14) at baseline. We found a decreased OPI in the test group after 8 days and the difference was statistically significant compared with the placebo group (P < 0.05). There were no significant treatment effects on the richness and global composition of the salivary microbiome.

Harms: In total, one participant in the test group claimed nausea and abandoned the project. In total, two participants did not like the taste of the mouthwash but used it as instructed. No other adverse events or side effects were reported.

Limitations: Short-term pilot trials may by nature be sensitive for selection and performance biases and are not designed to unveil persisting effects.

Conclusion: Daily use of enzyme-containing mouthwash reduced the amount of dental biofilm in adolescents under treatment with the fixed orthodontic appliances, without affecting the composition of the salivary microbiota.

Ethical approval: Approved by the Regional Ethical Board, Lund, Sweden (Dnr 2020-05221).

Clinical trial registration: NCT05033015.

© The Author(s) 2022. Published by Oxford University Press on behalf of the European Orthodontic Society.

Figures

Figure 1.

Flow chart of the trial according to CONSORT 2010.

Figure 2.

Relative change in orthodontic plaque index (OPI) scores from baseline to follow-up in the test and placebo groups. The vertical bars denote the standard error. The decrease in the test group was statistically significant (P < 0.05).

Figure 3.

(A) Stacked bar plot showing the relative abundance in the percentage of the 11 most abundant genera for each baseline sample (n = 29). The ‘other’ category contains all the lower abundant genera. (B) Boxplot showing the pairwise Bray–Curtis dissimilarity between baseline and follow-up sample for the placebo (red) and test (blue) group, with no statistical difference between groups (P = 0.704). (C) Barplot showing the change in richness from baseline to follow-up for each subject. We measured the richness by counting the number of unique operational taxonomic units (OTUs) in each sample and the subjects are visualized according to the placebo (red) and test (blue) groups. No statistically significant change was found between the groups, but there was a trend toward an increased richness in the placebo group compared with the test group from baseline to follow-up (P = 0.06).

Figure 4.

(A) Boxplot showing the log2 ratio of the relative abundance of the eight significantly different OTUs between baseline and follow-up. The red box shows the change in abundance for the placebo group and the blue box shows the change for the test group. (B) Barplot showing the relative abundance for the eight significantly different OTUs in the percentage of all the samples. The bars are coloured according to taxonomic classification on genus level.