Effects of clinical local factors on thickness and morphology of Schneiderian membrane: A retrospective clinical study.

BACKGROUND: It was informed that the thickness of maxillary sinus membrane may be affected by the local and patient-related factors in the literature. PURPOSE: The aim of this retrospective study is to evaluate factors that may have an influence of the thickness and morphology of the maxillary sinus membrane. MATERIALS AND METHODS: A total of 414 cone beam computed tomography images of 207 patients were evaluated. Radiographic parameters were evaluated at each maxillary premolar and molar tooth regions. Statistical analysis was performed to assess the association between the maxillary sinus mucosa thickness and morphology. The following factors including gender, periodontal bone loss (PBL), bone density, amount of residual alveolar bone at the edentulous space, vitality of the teeth present, and anatomical relationship between the sinus floor and posterior teeth were evaluated. RESULTS: The mean thickness of maxillary sinus membrane ranged between 1.47 to 2.92 mm and was significantly thicker in male subjects (P < .05). Positive correlation was detected between the sinus membrane thickness values in each posterior tooth region (P < .05). Thickening of the membrane was noted in 53% of the scans. The most commonly observed morphological change was flat thickening of the membrane (21%). No correlation was found between the evaluated local factors on the thickness and morphology of the maxillary sinus membrane (P > .05). CONCLUSIONS: Tooth vitality, residual alveolar bone height, and PBL seem to have no effect on the thickness and morphology of the maxillary sinus membrane.

The radiological evaluation of posterior superior alveolar artery topography by using computed tomography.

BACKGROUND: Posterior superior alveolar artery (PSAA) is the most important limiting anatomic structure while lateral approach sinus surgeries. PSAA should be taken into consideration to avoid bleeding during preparation of bony window. PURPOSE: The aim of this article was to inform topography of PSAA and to evaluate measurements of this vital structure. MATERIALS AND METHODS: Three hundred and fifty-four cone-beam computed tomography (CBCT) images of PSAA from 177 patients were evaluated retrospectively. Localization of PSAA, diameter of PSAA, classification of PSAA diameter, distance between PSAA and crest, buccal bone thickness, palatal bone thickness, crest height, and crest width were recorded for each posterior tooth separately. RESULTS: The mean age of 177 patients was 54.05 ± 18.33 years. Although the most frequent localization of PSAA was intraosseous in premolar region, they were below Schneiderian membrane in molars. PSAA diameter was measured frequently less than 1 mm for all posterior teeth. Although palatal bone thickness was higher in premolar region than molars, no statistical relationship was found between tooth region and buccal bone thickness (P > 0.05). The width of residual ridge was measured both wider apically and posteriorly. Positive correlation was observed between buccal bone thickness and PSAA diameter in first molar and premolar regions (P < 0.05). CONCLUSIONS: Detailed evaluation of patients by CBCT provided us the opportunity to draw topography of PSAA and inform about overall measurements of PSAA in all posterior teeth region.

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.