This investigation aimed to establish the frequency and distribution patterns of maxillary sinus (MS) pathologies originating from periapical (PA) endodontic lesions, to compare the primary and persistent forms of apical periodontitis (AP), and to examine the associations between distinct AP categories and endodontic procedures. A retrospective evaluation of 400 cone-beam computed tomography (CBCT) volumes from individuals referred to the Radiology Department at the College of Dentistry, King Abdulaziz University, was undertaken. The analysis focused on identifying PA lesions in the maxillary posterior dentition, classifying MS disease types, and assessing their spatial relationship with root apices, PA pathoses, and the antral floor. Statistical methods were applied to explore the interrelationships among the investigated variables. PA lesions were detected in 54% of initial infections and 46% of recurrent infections. In 56% of instances, the pathosis was restricted to the bone. MS disease was evident in 28% of cases presenting with persistent infections (P < 0.05). Unilateral sinus involvement was noted in 68% of cases, whereas bilateral manifestation accounted for merely 10% (P < 0.05). PA mucositis had a markedly higher incidence than PA osteoperiostitis, particularly in cases dominated by primary endodontic infections. These observations yield crucial knowledge regarding the interplay between MS disorders and endodontic pathoses, potentially guiding clinical therapeutic decision-making.
