Evaluation of single tooth loss to maxillary sinus and surrounding bone anatomy with cone-beam computed tomography: A multicenter study

Background: Posterior maxillary tooth loss may complicate the implant treatment due to the alterations in alveolar anatomy and maxillary sinus pneumatization. This study aimed to comprehensively examine the anatomical structure of this region from cone-beam computed tomography (CBCT) images. Materials and Methods: The posterior maxilla regions with single tooth loss were analyzed by dividing the variables into 3 subgroups from images of 597 patients chosen from 1160 CBCTs. Variables associated with sinus membrane (SM), sinus dimensions, ostium, septa, sinus neighborhood, alveolar bone height (ABH) and width (RW), posterior superior alveolar artery (PSAA), and adjacent roots were evaluated. Results: The majority of the patients demonstrated 0 to 5 mm membrane thickness. Irregular SM thickening was lower for female patients. While females showed higher number of narrow sinus, males had higher RW than females. Sinus augmentation classification showed negative correlation with ABH, root-tip sinus floor and edentulous site classification. Posterior septa height was correlated with number of septa and ABH. PSAA diameter and location were also correlated between each other. Conclusion: The present results define formation of a sinus space with 11 mm coronal and 16 mm apical width after single tooth loss. A flat or semispherical thickening around 4 mm is usual in most cases with 51% possibility of anterior septum existence. A ridge anatomy, around 7.5 mm ABH and 7.2 to 9.3 RW from coronal to apical, complements this anatomy. Further studies are needed to clarify the reasons behind the SM and crestal anatomy variations between genders.