This study characterized maxillary sinus mucositis (SIMS) adjacent to teeth with apical periodontitis (AP), and assessed its resolution three months after endodontic treatment. 29 subjects who maxillary posterior teeth with AP were imaged with cone-beam computed tomography (CBCT). Resolution of SIMS was assessed with CBCT three months after treatment, and periapical healing was assessed using the PAI after six months. Four non-compliant subjects were discontinued and SIMS was identified in 14/25 subjects (56%). Three months post-treatment, SIMS was resolved fully in 3/10 subjects (30%), and partially in 3/10 subjects (30%). Six months post-treatment, 6/10 subjects (60%) were classified as healed.
