Does residual bone thickness apical to periodontal defect play a major role in maxillary sinus mucous membrane thickness?: A cone-beam computed tomography-assisted retrospective study.

Background: The mucous membrane of the maxillary sinus is very sensitive to foreign bodies and infections. Any triggering may lead to mucous membrane thickening (MMT). Residual bone thickness (RBT) is the remaining bone apical to the periodontal defect until the floor of the maxillary sinus acts as a barrier for the periodontal infections to reach the sinus.