Accuracy of Schneiderian membrane thickness: a cone-beam computed tomography analysis with histological validation

Objectives: Cone-beam computed tomography (CBCT) has been used in the literature to evaluate Schneiderian membrane thickness (SMT), but its accuracy has never been validated. The primary aim of this study was to compare the SMT measured by CBCT to the gold standard histological assessment. The correlations between SMT and anatomical structures of the maxillary sinus and alveolar bone were also tested. Materials and Methods: Fourteen fresh cadaver heads were used for the study, and 28 sinus lift augmentation procedures were performed to obtain the membrane samples. Samples were fixed in formalin and stained with hematoxylin-eosine and Masson trichrome. Specimens were measured by optic microscope at three points, and a mean was obtained. Anatomical landmarks were used to accurately position the CBCT slice, so the SMT could be measured in predetermined locations. Wilcoxon signed-rank test was used to compare values of histological and CBCT measurements, and Spearman's correlation coefficient was calculated to examine the relationship between thickness and anatomical parameters. Results: A total of 597 histological measurements were performed, and the mean SMT thickness was 0.30 +/- 0.17 mm. The mean CBCT membrane thickness was 0.79 +/- 0.52 mm. A statistically significant difference from histological and radiological readings was observed (P = 0.000). Interestingly, 87.77% histological measurements had membrane less than 0.5 mm in thickness compared to 26.66% in CBCT assessment. Conclusions: Within the limitation of this study, the median histological Schneiderian membrane thickness was 0.30 mm. Cone-beam computed tomography assessment was 2.6 times higher than the histological examination.