Relationship between zygomatic process morphology and maxillary sinus pneumatization

Abstract

Recognizing the characteristics of the zygomatic process of the maxilla (ZPM) has several applications in implant dentistry and orthodontics. The present study evaluated the relationship between ZPM morphology, as obtained from panoramic images, and sinus pneumatization within the ZPM, according to cone-beam computed tomography (CBCT). CBCT and panoramic images of 300 patients were obtained, and the patients were divided into three age groups: Group I (15-34 years), Group II (35-55 years), and Group III (≥ 55 years). ZPM morphology was classified into J-shaped and non-J-shaped types based on panoramic images. The ZPM volume, maxillary sinus volume, and extent of sinus pneumatization within the ZPM were measured using CBCT scans, and their relationship to ZPM morphology classification was evaluated. Statistical analyses were performed using the Shapiro-Wilk test, one-way ANOVA, independent sample t-test, Mann-Whitney U test, Kruskal-Wallis test, and chi-square test (α = 0.05). Participants ranged in age from 17 to 82 years, and 67% were female. Most ZPMs were J-shaped (75%). J-shaped ZPMs had significantly greater sinus volume (1.83 ± 0.81 cm³), sinus pneumatization (53.56 ± 12.60%), and ZPM volume (3.50 ± 0.98 cm³) compared to non-J-shaped ZPMs (P < 0.05). Male participants had significantly larger ZPM volumes than females (P = 0.039). Sinus pneumatization and maxillary sinus volume were comparable across age groups and between gender. The presence of a non-J-shaped ZPM might be associated with less sinus pneumatization than J-shaped ZPMs, regardless of the patient's age or gender. Therefore, non-J-shaped ZPMs might offer more bone availability for various applications in dentistry.

Keywords: Cone-beam computed tomography; Maxillary sinus pneumatization; Panoramic; Radiography; Zygomatic process of the maxilla.

Fig. 1

The classification of ZPM according to panoramic view: A) J-shaped; B) U-shaped; and C) V-shaped

Fig. 2

Adjusting the orientation of the patient’s head: A) In the sagittal plane, the anterior and posterior nasal spines were connected (yellow dashed line). Then, the horizontal plane was adjusted in a way that became parallel to the yellow dashed line; B) In the coronal plane, a pink dashed line was drawn along the floor of the nasal cavity. The head position was adjusted so that this pink line became parallel to the horizontal plane, ensuring standardized orientation across all cases

Fig. 3

Localization of ZMS: A) In the axial view, the first section in which ZMS was identified was selected (yellow arrow points to ZMS); B) the vertical plane (red line) was aligned with the ZMS; C) in the coronal view, the first section, in which the lower border of the zygoma connects to the maxilla, was selected (pink arrow)

Fig. 4

Drawing the measuring cube: A) In the coronal section, the inferior side of the cube was aligned with an imaginary line extending from the nasal floor. The medial side of the cube aligns with the imaginary line that is tangential to the buccal part of the alveolar process of the maxilla (red line), and the orbital floor forms the superior side of the cube; B) In the axial section, the anterior wall of the maxilla forms the anterior side of the cube, the lateral side of the cube is aligned to the ZMS (vertical red line), and the posterior side of the cube is aligned with the horizontal green line, which defined the junction between the zygoma and maxilla

Fig. 5

Measuring the ZPM volume and the level of maxillary sinus pneumatization into the ZPM: A) After selecting the free region grow tool, in the axial section, mark the bony border of the ZPM in the cube until it reaches the orbital floor. B) After measuring the ZPM volume, select the free region grow tool again and start marking the border of the maxillary sinus in the ZPM (yellow line highlights the ZPM border)