LAUSR

OBJECTIVES The location of the maxillary sinus significantly affects the orthodontic treatment, particularly when temporary anchorage devices (TADs) are taking place. The current study aims to evaluate the maxillary sinus size and location in a skeletal class II population. MATERIALS AND METHODS The pre-orthodontic treatment CBCT images of the skeletal class II population were selected. The sinus's volumetric size, height, width, and depth were measured and compared among different skeletal vertical patterns and between genders. In addition, the height and width of the alveolar bone surrounding the maxillary sinus floor were quantified in the same manner. RESULTS Patients who displayed a high-angle skeletal pattern had significantly greater maxillary sinus dimensions, shorter vertical distance between the maxillary sinus floor and the alveolar bone crest, and thinner alveolar bone surrounding the maxillary sinus. Meanwhile, the maxillary sinus dimension measurements were positively correlated with the SN-MP angle in both genders but only correlated with ANB angle in females. On the other hand, the vertical distance between the maxillary sinus floor and the alveolar bone crest was negatively correlated with the SN-MP angle in males but the ANB angle in females. CONCLUSIONS In the skeletal class II population, the high-angle patients faced a higher risk of maxillary sinus perforations by TADs. In addition, gender-related variations were noticed warranting clinical attention, as males have a higher potential for maxillary sinus penetration from TAD placement than females. CLINICAL RELEVANCE Maxillary posterior alveolar TADs are often prescribed to achieve the distalization of maxillary posterior teeth in class II patients. The current study provided more insight into the "safe zone" for TAD placement related to the maxillary sinus.