Empirical Analysis of the Effectiveness of Motivational Interviewing in Improving Oral Hygiene Compliance Among Orthodontic Patients in Lagos

Motivational interviewing is a patient-centred communication approach with demonstrated efficacy in health behaviour change, and empirically evaluating its application to orthodontic oral hygiene compliance in a Lagos tertiary setting fills an important gap in Nigerian orthodontic clinical research. This study empirically evaluated the effectiveness of motivational interviewing delivered by dental hygienists on plaque index improvement and oral hygiene compliance among orthodontic patients at Lagos University Teaching Hospital over a 6-month period. A randomised controlled trial design was employed, assigning 80 orthodontic patients to motivational interviewing sessions (n = 40) or standard oral hygiene instruction (n = 40) at appointments 1, 2, and 4. Plaque index scores and patient compliance with inter-proximal cleaning were assessed at baseline, 3, and 6 months. The MI group showed significantly lower plaque index scores at 3 months (mean 1.12 versus 1.67, p < 0.001) and 6 months (mean 0.94 versus 1.58, p < 0.001). Compliance with interdental brush use was significantly higher in the MI group (72.5 percent versus 42.5 percent at 6 months, p < 0.01). MDAS anxiety scores declined more in the MI group. The treatment effect size was large (Cohen's d = 0.89). The study provides original empirical evidence for MI efficacy in Nigerian orthodontic practice and recommends training dental hygienists in motivational interviewing techniques, developing a structured MI protocol for orthodontic clinics, and evaluating integration into orthodontic consent and onboarding processes. Keywords: motivational interviewing, orthodontic compliance, oral hygiene, plaque index, Lagos University Teaching Hospital