The effect of mastic mouthwash on halitosis and oral hygiene in orthodontic patients: a randomized clinical trial.

Background/objectives: The aim of this trial was to investigate the effect of mastic mouthwash on halitosis using as a proxy the levels of the Volatile Sulfur Compounds (VSCs), and the effect on plaque and gingival indices in adolescents undergoing orthodontic treatment with fixed conventional labial appliances.

Subjects/methods: The study was a double-blinded, placebo-controlled, parallel-group, randomized clinical trial. Thirty patients with fixed orthodontic appliances were randomly allocated at a 1:1 ratio, to either the mastic-mouthwash or the placebo-mouthwash group. Eligibility criteria included ages between 13 and 18, active orthodontic treatment with fixed appliances, good general health, and total initial VSCs levels above 150 ppb. The primary outcome was the objective hydrogen sulfide (H2S) level, measured with the Oral ChromaTM device. The secondary outcomes were (1.) the methyl-mercaptan (CH3SH) and (2.) dimethyl sulfide [(CH3)2S] levels, measured with the same device, (3.) the subjective perception of the own malodour via questionnaires, and (4.) the oral hygiene assessed with the use of the Modified Silness and Löe Plaque Index (PI-M) and the Silness and Löe Gingival Index (GI) at baseline (T0) and after 2 weeks (T1). Stratified randomization by gender was used, and allocation was concealed with opaque numbered sealed envelopes.

Results: H2S level dropped from 221.00 ppb (T0) to 125.00 ppb (T1), and the difference between treatment groups was statistically significant in favour of the mastic group (coef: 72.34, 95% CI: 8.48, 136.27, P = 0.03). The levels of the other VSCs, the subjective measurements of oral malodour, and the oral hygiene indices did not differ between treatment arms.

Limitations: The objective organoleptic assessment by a calibrated examiner was not performed.

Conclusions/implications: Mastic mouthwashes could be an alternative treatment for adolescent patients suffering from halitosis during orthodontic treatment with fixed appliances.

Registration: The trial was registered at ClinicalTrials.gov (identifier: NCT05647369).