Background: Different local factors may affect the maxillary sinus membrane thickening (MSMT). The aim of 
this study is to assess the effect of periodontal bone loss (PBL) of maxillary molars on the MSMT, using a 3-
dimension (3D) cone beam computed tomography (CBCT) imaging. 
Methods: This is a retrospective observational CBCT study of 126 patients with PBL of maxillary molar that 
were selected and evaluated for presence of MSMT on a reconstructed sagittal cut. On a cut of the highest point 
of the MSMT the length of the thickening was recorded and correlated with severity of PBL and age using 
Spearman correlation coefficient. 
Results: Statistically significant difference was found between the group with MSMT and the group without 
thickening with p<0.001. There was a positive poor relationship between the presence of mucosal thickening 
and PBL of 0.019. A negative poor relationship of -0.111 was found between MSMT and age, with no 
statistically significant difference between different age group of 20-40 y and 41-60 y, where p=0. 212. 
Conclusion: The presence of PBL may have an impact on the state of maxillary sinus membrane