In patients undergoing fixed orthodontic treatment, does the use of a Waterpik® in addition to a manual toothbrush, compared to using a manual toothbrush alone, improve oral hygiene? A randomised controlled trial.

Aims: To assess whether the use of a Waterpik® in addition to a manual toothbrush improves oral hygiene in patients wearing fixed orthodontic appliances.
Design: single-centre, single-operator, two-arm, parallel-group, stratified, single-blind, randomised controlled clinical trial with a 1:1 allocation ratio.
Setting: A single orthodontic department in an NHS District General Hospital in York (UK).
Subjects: 40 fit and well patients aged 10-20 accessing upper and lower fixed orthodontic therapy.
Methods: Participants were randomly allocated to the control group (manual toothbrush) or intervention group (manual toothbrush and Waterpik®). Plaque index, gingival index and interdental bleeding index were recorded as primary outcomes at baseline, 8-weeks, 32-weeks, and 56-weeks. Secondary outcome measures assessed were soft tissue trauma, adherence with oral hygiene regime and satisfaction with oral hygiene regime. A mixed model analysis was used to assess differences between groups.
Results: Interim analysis is performed due to COVID-19 disruption of the project progress. 34 participants have been recruited. 4 participants have completed the trial. The remaining patients are at various points with approximately 50% of data collected. The overall differences between the groups were as follows:
Orthodontic modification of plaque index: 0.02 (p = 0.85, 95% CI: -0.2, 0.2)
Gingival index: -0.06 (p = 0.45, 95% CI: -0.21, 0.09)
Interdental bleeding index: -5.5 (p = 0.418, 95% CI: -19.29, 8.21)
There was no difference in terms of soft tissue trauma.
It was not possible to assess adherence with and satisfaction with oral hygiene regime in the interim analysis.
Conclusions: There is no statistical or clinical benefit in the use of a Waterpik® in addition to a manual toothbrush for patients wearing fixed orthodontic appliances.
However, as the data for the trial is incomplete and the analyses were performed on limited sample size, any conclusions should be interpreted with caution.