152 - Randomized Controlled Trial of Motivational Interviewing in Orthodontic Oral Hygiene

Purpose:
To evaluate the effect of a motivational interviewing (MI)–based intervention compared with standard oral hygiene instruction (OHI) on clinical and patient-reported outcomes among adolescent orthodontic patients.

Methods:
Fifty adolescents aged 14–19 years undergoing fixed orthodontic treatment were randomized to receive MI or standard OHI. The study was Institutional Review Board–approved (IRB-300014350) and registered at ClinicalTrials.gov. Clinical examiners and participants were blinded to group allocation. Plaque Index (PI), Gingival Index (GI), and Decayed, Missing, and Filled Teeth (DMFT) were recorded at baseline, 4–6 weeks, and 3 months by calibrated examiners. Patient-reported outcomes, including knowledge, attitudes/motivation/self-efficacy, oral hygiene practices, and symptoms, were assessed using a validated questionnaire. Between-group comparisons for PI, GI, symptom scores, and questionnaire-based outcomes across time points (T0, T1, and T2) were analyzed using the Chi-square test, while continuous outcomes were evaluated using Student’s t-test. At T2, associations between PI or GI and questionnaire-based outcomes were assessed using the Chi-square test. Statistical analyses were performed using SAS® 9.4, with significance set at p < 0.05.

Results:
At 3 months, the MI group demonstrated significantly improved clinical outcomes compared with the control group, with reductions in PI and GI (p < 0.0001), while no significant difference was observed in DMFT (p = 0.17). Significant improvements were observed in knowledge, attitudes, and oral hygiene practices, with most knowledge and attitude measures reaching statistical significance (p < 0.05). Self-reported symptom scores decreased significantly in the MI group (mean: 1.12 to 0.17) compared with minimal change in the control group (mean: 1.36 to 1.12), with a significant between-group difference (p = 0.00053). Improvements in symptoms were accompanied by reductions in PI and GI, indicating strong alignment between patient-reported and clinical outcomes.

Conclusions:
A motivational interviewing (MI)–based intervention resulted in significant improvements in plaque control, gingival health, patient-reported symptoms, and oral health behaviors among adolescent orthodontic patients compared with standard oral hygiene instruction. These findings support MI as an effective patient-centered approach for improving both clinical and behavioral outcomes. Continued follow-up to six months will evaluate durability.