A cone beam computer tomography-based assessment of the maxillary air sinus dimensions using the facial index classification

Recent research indicates that the facial skeleton affects the maxillary sinus (MS) anatomy, spurring further investigation into variations in the size of the MS based on facial phenotypes. Orthodontic and maxillofacial surgeon show great interest in the facial phenotype, as it is directly affected by the MS morphology, growth and development. This study aimed to assess various MS dimensions and evaluate their characteristics with respect to the facial index (FI), which classifies facial phenotypes. The study included cone beam computed tomographic (CBCT) images of 348 adults in Saudi Arabia. A vision iCAT software was used to extract and measure both facial and MS dimensions of the subjects’ CBCT scans. The subjects were classified into five categories based on their FI classification (which was obtained from measured facial height and width), namely: hypereuryprosopic, euryprosopic, mesoprosopic, leptoprosopic, and hyperleptoprosopic. A one-way ANOVA conducted showed that the sizes of MS were significantly different with respect to different facial phenotype. Hypereuryprosopics and euryprosopics had the widest MS width, hyperleptoprosopic had the highest MS height and the euryprosopics had the widest inter-sinus distance. Linear regression analysis demonstrated regression equations for clinicians to predict MS dimensions from the facial dimensions. We provided evidence that strong morphological differences exist in MS dimensions among individuals, based on their specific facial phenotype. Understanding these relationships is therefore essential to surgeons when performing maxillofacial or orthodontic procedures. The regression models obtained could be used to empirically calculate MS dimensions, which can come in handy during patients’ preoperative preparations.