Association of Skeletal Facial Pattern With Treatment Response of Obstructive Sleep Apnoea Using Mandibular Advancement Devices - A Cluster Analysis.

Mandibular advancement devices (MADs) are an effective treatment for obstructive sleep apnoea (OSA), though individual responses to therapy can vary. This study aims to: (1) examine how craniofacial characteristics are associated with MAD effectiveness to refine patient selection and improve outcomes; and (2) assess the association of skeletal facial patterns with treatment efficacy and mandibular advancement. This retrospective study used data from a previous quasi-experimental study. Analysis was conducted with two-piece adjustable devices, following a standardised protocol. K-means clustering analysis categorised the sample into subtypes using clinical, polysomnographic, and anatomical data to evaluate MAD treatment response. Patients were also classified by growth pattern, and treatment response and mandibular advancement were compared across facial patterns. The study included 112 patients. Of these, 41 patients (36.61%) were assigned to Cluster 1 and 71 patients (63.39%) to Cluster 2. Cluster 1 patients had more severe OSA, with higher ESS, BMI, T90%, and AHI, along with a vertical facial pattern and narrower airways. Treatment response rates were significantly lower in Cluster 1 compared to Cluster 2. Among facial pattern groups, 32 patients were hyperdivergent, 46 were neutral, and 34 were hypodivergent. The responder rate was significantly lower in the hyperdivergent group, indicating reduced treatment effectiveness. This study suggests that the efficacy of OSA treatment with MADs may be associated with anatomical subtypes. Cluster 1 patients showed a lower response rate compared to Cluster 2. Additionally, patients with hyperdivergent patterns may have a less favourable response to MAD treatment.