Anatomical Possibilities of the Alveolar Bone at the Upper Second Premolar Level.

Background and Objectives: The upper posterior teeth are typically regarded as being exclusively inferior to the maxillary sinus (MS). The expansion of the nasal fossa above the maxillary alveolar base (MAB) needs better investigation. The hypothesis was raised that the MAB in the upper premolar region, which is usually addressed by surgeons for the elevation of the antral floor, is not exclusively beneath the MS. Therefore, we aimed to document the possible upper relations of the MAB as antral, nasal, or both. Materials and Methods: A total of 145 CBCT scans were used to study four types of MAB: type 1-antral; type 2-antral with a palatal recess; type 3-antral and nasal; type 4-nasal. In type 2, the orthoradial width of the alveolar bone, the rectilinear width of the antral floor, and the maximum depth of the palatal recess were measured. For type 3, the MAB width and the straight widths of the antral and nasal segments of the MAB were measured. Results: Type 1 was found in 67.24%, type 2 in 13.45%, type 3 in 16.21%, and type 4 in 3.1% of the 290 MSs investigated. Palatal recesses were found in 11.72% of the MSs on the right side and 15.17% of the MSs on the left side. Types 1 and 2 exhibited strongly statistically significant bilateral symmetry (Pearson's Chi2 = 86.42, p < 0.001). Type 3 correlated equally with contralateral types 1 and 3. The bilateral symmetry for types 1-3 was stronger in the males (Pearson's Chi2 = 47.83, p < 0.001) than in the females (Pearson's Chi2 = 56.96, p < 0.001). There were no statistically significant associations between sex and the unilateral anatomical type. Conclusions: The MAB in the upper second premolar area should not be considered to be exclusively antral during surgeries or in anatomical teaching.

Middle meatal nasal recesses of the maxillary sinuses and dangerously modified nasal anatomy.

Pneumatisation of the maxillary sinus (MS) is variable. The archived cone-beam computed tomography file of a 54-year-old female was retrospectively evaluated anatomically. Nasal or retrobullar recesses of the MSs (NRMS) were found. The MSs were bicameral. NRMSs extended from the postero-lateral chambers of the MSs into the lateral nasal walls. The right NRMS was reached superior to the middle turbinate and the ethmoidal bulla was applied on its anterior side. The left NRMS had two medial pouch-like ends, one beneath the ethmoidal bulla and the other on the anterior side of the basal lamella of the middle turbinate. Additional anatomical findings were the uncinate bulla, infraorbital recesses of the MS, maxillary recess of the sphenoidal sinus, and atypical posterior insertions of the superior nasal turbinates, maxillo-ethmoido-sphenoidal and ethmoido-sphenoidal. The NRMS is a novel finding and could lead to erroneous endoscopic corridors if not documented before the interventions.

The sinus septi nasi and other minor pneumatizations of the nasal septum.

The osseous nasal septum (NS) consists of the perpendicular plate of the ethmoid bone (PPE) and the vomer bone. Few studies evaluated the possibilities of septal pneumatization of the PPE, or adjacent to it. We aimed to observe the anatomical possibilities of NS pneumatizations. A retrospective lot of cone-beam computed tomography (CBCT) files was used. One hundred seventy-one CBCT files from 51 males and 120 females were documented. There were found 46 files that were null for septal pneumatization. The other cases (73.1%) had different septal pneumatizations extended from neighboring air spaces. Pneumatized crista galli (CG) exclusively extended from a frontal sinus was found in 7.01% of cases. The frontal sinuses had minor extensions anterior to the PPE in 7.6% of cases. Unique or double pneumatizations of the sphenoidal rostrum extending within the posterior part of the PPE were detected in 71.34% of cases. In six cases were found ethmoidal pneumatizations of the PPE, either from an anterior ethmoid cell, or from a posterior one, or from a pneumatized CG. In this last case was found a sinus septi nasi of 25.37 mm sagittal size. The supra-septal recesses of the ethmoid air cells were roofing the respective nasal fossa. As all the morphological possibilities of NS pneumatization involve the upper part of the PPE, they should be adequately discriminated anatomically, as well as when the NS and the cribriform plate of the ethmoid bone are approached surgically.