Visibility, location, and morphology of the primary maxillary sinus ostium and presence of accessory ostia: a retrospective analysis using cone beam computed tomography (CBCT)

Relationship of the accessory maxillary ostium to mucosal thickening and maxillary sinus cysts: a 3D segmentation study

OBJECTIVES

We aimed to investigate the relationship between the presence of the accessory maxillary ostium (AMO) with mucosal thickening (MT) and maxillary sinus cysts (MSCs).

STUDY DESIGN

This single-center retrospective study included patients who underwent paranasal sinus computed tomography (CT) between November 2022 and February 2023. We excluded patients with natural maxillary ostium (NMO) occlusion. Two radiologists evaluated the presence of AMOs, MT, and MSCs in CT images and measured their dimensions using a three-dimensional volumetric analysis program.

RESULTS

We included 125 patients (mean age: 36.47 ± 16.0 years; male/female: 67/58). In total, 65 patients (52%) had single or multiple AMOs. No significant relationship was found between the presence of an AMO and the presence of MT on either side (P ≥ .306). There was a statistically significant difference between the presence of an AMO and MSC on the right side (P = .002), but not on the left side (P = .477). The diameter of the AMO and the distance from the AMO to the maxillary sinus floor were not correlated with mucosal thickness or MSC volume, but the distance from the AMO to the sinus floor had a small positive correlation with total maxillary sinus volume.

CONCLUSIONS

The presence of an AMO and its increased diameter may not contribute to ipsilateral maxillary sinusitis in patients whose unilateral or bilateral NMOs are not occluded.

Frequency of Accessory Maxillary Ostium in Patients With/Without Sinusitis, and Its Correlation with Anatomical Variations of Paranasal Sinuses: A Cone Beam Computed Tomography Study

This study assessed the frequency of accessory maxillary ostium (AMO) in patients with/without sinusitis and its correlation with anatomical variations using cone-beam computed tomography (CBCT). In this cross-sectional study, 244 CBCT scans were evaluated in two groups: with maxillary sinusitis having > 2 mm mucosal thickening and without max sinusitis as a normal group having normal or less than 2 mm mucosa. The CBCT scans of each group were carefully evaluated for the presence/absence of AMO, patency/obstruction of the primary maxillary ostium (PMO), and the presence of anatomical variations of the paranasal sinuses. Data were analyzed by independent t-test, Pearson Chi-square test, and Fisher's exact test (alpha = 0.05). CBCT scans of 134 females (54.9%) and 110 males (45.1%) with a mean age of 34.16 ± 19.01 years were evaluated. The presence of AMO had no significant correlation with maxillary sinusitis (P = 0.104). The two groups had no significant difference in the frequency of Haller cell, nasal septal deviation, and concha bullosa (P > 0.05). However, the frequency of paradoxical concha (PC; P < 0.001) and bifid concha (BC; P = 0.017) was significantly higher in the normal group, and the frequency of PMO obstruction was significantly higher in the sinusitis group (P < 0.001). AMO had no significant correlation with any anatomical variation in any group (P > 0.05). Gender had a significant effect on the presence of AMO (P = 0.013). The presence of AMO had no significant correlation with maxillary sinusitis. However, its frequency was significantly higher in females in normal group and males with sinusitis. The presence of AMO had no significant correlation with anatomical variations.

Comparative study of anatomical features of primary and accessory maxillary ostia between patients with obstructive sleep apnea and healthy controls

PURPOSE

The purpose of this study was to examine how the size and shape of the maxillary sinus and its ostia (the primary maxillary ostium and accessory maxillary ostium) relate to each other in patients with OSA using computed tomography (CT) scans. Additionally, the study aimed to explore whether or not obstructive sleep apnea (OSA) had an effect on these structures.

METHODS

CT images of patients diagnosed with OSAS and healthy participants were evaluated to compare the patency, location, dimension, and presence of PMOs and AMOs using the Mann-Whitney U, Student t, and chi-square tests. Also, intragroup correlations were analyzed by Spearman's correlation test.

RESULTS

Among 139 patients with OSA and healthy controls, there were significant variations in the average length (p = 0.001) and width (p = 0.008) of PMOs among the study groups. The mean maxillary sinus volume was significantly decreased in the OSA group (p = 0.001). A significant decrease in the maxillary sinus volume was observed in the OSA group (p = 0.001). In the OSA group, a significant correlation was observed between PMO obstruction and the presence of AMO (p = 0.004). The healthy group had significant correlations (r = 0.755, p = 0.000) between the vertical height and the distance between PMO and the maxillary sinus floor. Correlation analyses revealed positive, strong correlations between study variables such as the mean length and width of AMO and the vertical height of the maxillary sinus (r = 0.566, p = 0.000) in the OSA group.

CONCLUSIONS

The current study indicated significant differences in sinus volume, PMO occlusion, and AMO-related dimensions between patients with OSA and healthy controls.

Characteristics of maxillary sinus ostia and their correlation with anatomic variations of the osteomeatal complex: Indications for sinus floor elevation

Background

Knowledge of the anatomy and variations of the maxillary sinus is essential for reducing oral surgery complications, such as sinus floor elevation, and increasing surgery success. The CBCT images of 385 patients were examined.

Materials and Methods

The prevalence, localization, and height of PMO (Primer Maxillary Ostium) and AMO (Accessory Maxillary Ostium) were evaluated with respect to sex, dentition, dental treatment, Schneiderian membrane (SM) thickness, concha bullosa, Haller Cells, and septal deviation.

Results

The PMO was present in 87.3% of all patients. Further analysis showed that the mean PMO diameter was 1.42 ± 0.62 mm. Although 11.6% of the PMO was in the inferior region, 60.4% was in the middle and 28% in the superior region. The effect of age and SM on the height and diameter of the PMO was found to be statistically significant. An AMO was present in 20% of the CBCT images. The mean AMO diameter was 2.55 ± 1.25 mm. Although 45.4% of the AMO was in the inferior region, 48% was in the middle and 6.6% was in the superior region. Moreover, SM thickness seemed to influence the height. A significant positive relationship was found between the PMO and AMO height. Also, a significant relationship was observed between the presence of the AMO and septum deviation.

Conclusion

The presence of the AMO, PMO diameter, and height should be added to the preoperative evaluation criteria for the success of sinus floor evaluation. Specifically, sinonasal and demographic conditions should be carefully examined preoperatively for the long-term success of the surgery.

CBCT for Diagnostics, Treatment Planning and Monitoring of Sinus Floor Elevation Procedures

Sinus floor elevation (SFE) is a standard surgical technique used to compensate for alveolar bone resorption in the posterior maxilla. Such a surgical procedure requires radiographic imaging pre- and postoperatively for diagnosis, treatment planning, and outcome assessment. Cone beam computed tomography (CBCT) has become a well-established imaging modality in the dentomaxillofacial region. The following narrative review is aimed to provide clinicians with an overview of the role of three-dimensional (3D) CBCT imaging for diagnostics, treatment planning, and postoperative monitoring of SFE procedures. CBCT imaging prior to SFE provides surgeons with a more detailed view of the surgical site, allows for the detection of potential pathologies three-dimensionally, and helps to virtually plan the procedure more precisely while reducing patient morbidity. In addition, it serves as a useful follow-up tool for assessing sinus and bone graft changes. Meanwhile, using CBCT imaging has to be standardized and justified based on the recognized diagnostic imaging guidelines, taking into account both the technical and clinical considerations. Future studies are recommended to incorporate artificial intelligence-based solutions for automating and standardizing the diagnostic and decision-making process in the context of SFE procedures to further improve the standards of patient care.

Are maxillary sinus variations related to maxillary sinus diameters?

OBJECTIVES

The reasons why the maxillary posterior region is challenging for dentists are its structure and anatomical variations. For this reason, it is necessary to have complete knowledge about the anatomy of this region. In dentistry, necessary information for the desired evaluation in this region can be provided by CBCT. The fact that it provides a three-dimensional evaluation and has measurement reliability emphasizes its importance in surgical applications. The septa, haller cell, and accessory ostium are variations of the maxillary sinus. There are few studies in the literature examining the relationship between maxillary sinus diameters and its variations. The aims of this study are to determine the prevalence of maxillary sinus variations and the average of maxillary sinus diameters, to examine their relationships according to age and gender, and to evaluate the effects of maxillary sinus diameters on variations.

METHODS

In this retrospective study, CBCT images of 212 patients were examined. The examined CBCT images were analysed and recorded in more than one section. Descriptive statistics, chi-square tests, independent t test, one-way Anova tests were used to evaluate the data.

RESULTS

As a result, a statistically significant difference was observed between the variations, gender and age groups in terms of morphometric characteristics of the maxillary sinus. The most common variation was observed to be accessory ostium.

CONCLUSIONS

The rate of patients with at least one anatomical variation was 77.8%. For this reason, a detailed analysis should be performed to avoid complications before surgical procedures are performed in the area.

Analysis of risk variables for association with maxillary sinus mucosal thickenings: a cone-beam computed tomography-based retrospective study

PURPOSE

This study aimed to determine which patient-related, anatomical, pathologic, or iatrogenic variables may be directly associated with and which may have a modifying effect on the generation of maxillary sinus (MS) mucosal thickenings.

METHODS

A total of 278 cone-beam computed tomography (CBCT) scans obtained from 114 males and 164 females were evaluated. The protocol included the assessment of 21 candidate variables, of which 18 were bilateral and 3 were unique. The relationship among the study variables and the mucosal thickenings were examined individually and adjusted for confounding using univariate and multivariate binary logistic regression models.

RESULTS

The prevalence of mucosal thickenings was 71.20% at patient level and 53.40% at sinus level. The ostium height > 28.15 mm, the infundibulum length ≤ 9.55 mm, the infundibulum width ≤ 0.50 mm, along the occurrence of periapical lesions and slight-to-severe periodontal bone loss acted as strong/independent risk variables for MS mucosal thickenings. Confounding and interaction relationships between MS height and depth, and between the alveolar process type and the presence of foreign materials with respect to age stratum > 47.50 years might be also associated with the mucosal thickenings.

CONCLUSIONS

While increased ostium height, decreased infundibulum length/width, the presence of periapical lesions and periodontal involvement might be the foremost indicator variables for MS mucosal thickenings, there are synergistic relationships among the increased sinus height and depth as well as aging regarding atrophic/partially atrophic alveolar process status and the presence of foreign materials that may be also associated with a greater proportion of these mucosal abnormalities.

Current Applications of Deep Learning and Radiomics on CT and CBCT for Maxillofacial Diseases

The increasing use of computed tomography (CT) and cone beam computed tomography (CBCT) in oral and maxillofacial imaging has driven the development of deep learning and radiomics applications to assist clinicians in early diagnosis, accurate prognosis prediction, and efficient treatment planning of maxillofacial diseases. This narrative review aimed to provide an up-to-date overview of the current applications of deep learning and radiomics on CT and CBCT for the diagnosis and management of maxillofacial diseases. Based on current evidence, a wide range of deep learning models on CT/CBCT images have been developed for automatic diagnosis, segmentation, and classification of jaw cysts and tumors, cervical lymph node metastasis, salivary gland diseases, temporomandibular (TMJ) disorders, maxillary sinus pathologies, mandibular fractures, and dentomaxillofacial deformities, while CT-/CBCT-derived radiomics applications mainly focused on occult lymph node metastasis in patients with oral cancer, malignant salivary gland tumors, and TMJ osteoarthritis. Most of these models showed high performance, and some of them even outperformed human experts. The models with performance on par with human experts have the potential to serve as clinically practicable tools to achieve the earliest possible diagnosis and treatment, leading to a more precise and personalized approach for the management of maxillofacial diseases. Challenges and issues, including the lack of the generalizability and explainability of deep learning models and the uncertainty in the reproducibility and stability of radiomic features, should be overcome to gain the trust of patients, providers, and healthcare organizers for daily clinical use of these models.

The Use of CBCT in Evaluating the Health and Pathology of the Maxillary Sinus

The use of cone-beam computed tomography (CBCT) has been increasing in dental practice. This narrative review summarized the relevance and utilizations of CBCT to visualize anatomical structures of the maxillary sinus and common pathologies found in the maxillary sinus. The detection/visualization rate, the location and the morphometric characteristics were described. For sinus anatomy, the reviewed features included the posterior superior alveolar artery, sinus pneumatization, sinus hypoplasia, sinus septa, and primary and accessory sinus ostia. For pathology, the following items were reviewed: membrane thickening associated with periapical lesions/periodontal lesions, mucous retention cyst, and antrolith. The visualization and assessment of the maxillary sinus is very important prior to procedures that take place in close proximity with the sinus floor, such as tooth extraction, implant insertion, and sinus floor elevation. Some sinus pathologies may be associated with odontogenic lesions, such as periapical diseases and periodontal bone loss.

Anatomical Characteristics of the Accessory Maxillary Ostium in Three-Dimensional Analysis

Background and Objectives: The accessory maxillary ostium (AMO) can interfere with ventilation and drainage of the maxillary sinus, and therefore the importance of evaluating the anatomical features of the AMO has been emphasized. This study aimed to evaluate anatomical characteristics of the AMO together with the natural ostium (NO) using three-dimensional (3D) analysis and to assess the relationship between the AMO and maxillary sinus pathologies. Materials and Methods: This retrospective study included 394 sinuses in 197 patients. Using 3D computed tomography images, the prevalence of the AMO and concurrent sinus pathologies were examined. For patients with an AMO, 3D spatial positions of the AMO and NO related to adjacent anatomic structures and dimensions of the AMO and NO were evaluated. Results: A total of 84 sinuses showed single or multiple AMO, with a prevalence of 21.3%. The AMO was located superiorly by 30.1 mm from the maxillary sinus floor, inferiorly by 1.3 mm from the orbital floor, and posteriorly by 22.4 mm from the anterior sinus wall. The AMO was located 5.4 mm posteriorly and 0.7 mm inferiorly from the NO. On the same coronal plane as the NO or AMO, height from the maxillary sinus floor to the NO and AMO ranged from 19.4 to 45.8 mm and 14.5 mm to 41.9 mm, respectively. The mean horizontal and vertical dimensions were 5.9 mm and 4.6 mm for the NO and 2.8 mm and 3.0 mm for the AMO. We detected a significant association between the presence of the AMO and the mucosal thickening (p = 0.029). Conclusions: The results of this study suggest that, although the AMO and NO are mostly located in positions that do not limit sinus-related surgeries, such as maxillary sinus floor augmentation, the AMO and NO are also found in lower positions, which may be a detriment to the postoperative physiological function of the maxillary sinus and affect treatment outcomes.

The Relationship Between an Accessory Maxillary Ostium and Variations in Structures Adjacent to the Maxillary Sinus without Polyps

Introduction  The maxillary sinus and its variations are very important to dentistry and rhinology.

Objective  To investigate the effect of the accessory maxillary ostium (AMO) on the variations of adjacent structures of the maxillary sinus.

Methods  The computed tomography (CT) images of 400 patients were retrospectively evaluated. The prevalence of AMO was calculated. The relationship between morphological variations of adjacent structures of maxillary sinus such as agger nasi cell (ANC), Haller cell (HC), nasal septum deviation (NSD), hypertrophy of inferior concha (HIC), pneumatization of middle concha (PMC), mucus retention cyst (MRC), mucosal thickening (MT), and maxillary sinusitis (MS), as well as the presence of AMO, were investigated.

Results  Presence of AMO was diagnosed in 42 patients (10.5%), having been found in 4.5% of the patients only on the right side, in 1.25% of the patients only on the left side, and in 4.75% of the patients on both sides. There is an increasing incidence of ANC, HC, NSD, HIC, and PMC in the presence of AMO and MS. There is a decreasing incidence of MRC in the presence of AMO. Furthermore, AMO does not affect the incidence of MT.

Conclusion  This study showed that most parameters, except for MRC and MT, had increasing incidence in the presence of AMO. It is important for radiologists and rhinologists to have knowledge about the location of AMO and the presence of variations of MS adjacent structures to avoid surgical complications.

Anatomical variations of the ethmoid sinuses and their association with health or pathology of the ethmoid and maxillary sinuses in a Southern Chinese population: An analysis using cone-beam computed tomography

Purpose

The aim of this study was to evaluate the prevalence of clinically relevant anatomical variations of the ethmoid sinuses and their potential association with ethmoid and maxillary sinus pathologies on cone-beam computed tomography (CBCT) scans. Additionally, potential associations with different sides and demographic factors, including age and sex, were evaluated.

Materials and Methods

In total, 273 CBCT scans with complete ethmoid and maxillary sinuses were analyzed to determine the prevalence of Agger nasi cell, supraorbital ethmoid cell, Haller cell, Onodi cell, and ethmomaxillary sinus. In addition, the health or pathology of the ethmoid and maxillary sinuses was also recorded to assess correlations with the aforementioned variations.

Results

The prevalence of Agger nasi cell was found to be the highest (95.6%) in this study, followed by Onodi cell (60.4%), Haller cell (29.3%), and supraorbital ethmoid cell (19.4%). Ethmomaxillary sinus was the least common finding (16.5%). Males and persons above 61 years of age had a significantly higher frequency of supraorbital ethmoid cell and Onodi cell, respectively. However, no significant relationships were noted between anatomical variations of the ethmoid sinus and pathologies of the ethmoid or maxillary sinus.

Conclusion

There was a high prevalence of ethmoid sinus variations in this Southern Chinese population. The prevalence of Agger nasi cell and Onodi cell was higher than that of other anatomical variations of the ethmoid sinuses. Anatomical variations of the ethmoid sinuses were not associated with ethmoid or maxillary sinus pathologies in this patient cohort.

Investigation of the accessory maxillary ostium: a congenital variation or acquired defect?

OBJECTIVE

We sought to determine whether an accessory maxillary ostium (AMO) is a congenital or acquired condition and we investigated concomitant sinus pathologies associated with this structure.

METHODS

Paranasal sinus CT examinations of individuals aged ≥13 years and <13 years were compared retrospectively. In total, 552 sinuses of 276 patients aged ≥13 years (Group 1) and 284 maxillary sinuses of 142 children aged <13 years (Group 2) were evaluated. Patients were classified as AMO-positive or -negative. The following features were evaluated in Group 1: AMO presence, mucus retention cysts, mucosal thickening, sinusitis of the maxillary sinus, nasal septum deviation, concha hypertrophy, concha bullosa, primary ostium obstruction, uncinate process atelectasis, paradox concha, Agger nasi and Haller cells, and sinus hypoplasia. The sizes and locations of AMOs were also evaluated. The presence of an AMO and sinusitis were evaluated in Group 2.

RESULTS

AMOs were detected in 122 sinuses in Group 1. In the AMO-positive group, sinusitis, mucosal thickening, and primary ostium obstruction were significantly more common than in the AMO-negative group (p < 0.00001). Statistically significant associations were not observed between AMO presence and other parameters. AMOs were present in two sinuses in Group 2.

CONCLUSION

Our results suggest that AMOs are acquired defects caused by sinus diseases. The rare occurrence of these structures in patients aged <13 years suggests that they may be a perforation or secondary drainage pathway in patients with sinusitis or primary ostium obstruction.

Ancestry-based variation in maxillary sinus anatomy: Implications for health disparities in sinonasal disease

Paranasal sinus drainage is mediated by mucociliary transport and gravity. However, human orthograde posture, along with the superior positioning of the maxillary sinus (MS) ostium, increases reliance on the mucociliary system. Previous research has thus suggested that differences in MS size and shape may impede mucociliary clearance, potentially contributing to disparities in sinusitis susceptibility. To further investigate this hypothesis, this study collected 29 three-dimensional (3D) coordinate landmarks and seven linear measurements of MS morphology from 167 computed tomography (CT) scans of crania of European, East Asian, or Equatorial African ancestry. MANOVA results reveal the Asian-derived individuals are characterized by both a significantly taller MS (F = 14.15, p <  0.0001) and a significantly greater distance from the MS floor to the ostium (F = 17.22, p <  0.0001) compared to those of European and African ancestry. A canonical variate (CV) analysis conducted on 3D landmark data provides corroborative results, distinguishing Asian-derived individuals predominantly on the basis of a relatively lower MS floor. As a greater distance between the MS floor and ostium may impede mucociliary clearance, our results suggest MS anatomy may be a more prominent factor in chronic sinusitis among individuals of Asian ancestry compared to those of European and African ancestries. This provides tentative evidence of an anatomical etiology for chronic sinusitis even in the absence of anatomical variants/abnormalities (e.g., nasal polyps, concha bullosa, Haller's cells, and Agger nasi cells). Further research into the relationship between MS anatomy and sinusitis, in addition to socioeconomic inequalities of healthcare, is warranted to continue evaluating possible contributions to health disparities.

Rare Variation of Accessory Maxillary Ostium

Accessory maxillary ostium (AMO) is one of the anatomical variations in the maxillary sinus. It can be present in different sizes, shapes, and locations. We here reported a case of a rare variation of AMO with large size in a patient with chronic rhinosinusitis. It is important to identify the presence of AMO especially in patients with chronic rhinosinusitis as it can lead to mucus recirculation and disease persistence.

Involvement of the maxillary sinus ostium (MSO) in the edematous processes after sinus floor augmentation: a cone-beam computed tomographic study

Background

After sinus floor augmentation, a thickening of the sinus mucosa has been described. The aim of the present study was to evaluate the involvement of the maxillary sinus ostium in the edematous processes after a sinus floor augmentation procedure.

Methods

Seventy-two cone-beam computerized tomographies (CBSTs) were taken before sinus floor augmentation and after 1 week and 9 months from surgery and analyses. Sinus mucosa thickness and area, ostium diameter and patency, and extension of the post-surgical transient mucosal thickening in relation to the ostium were evaluated on the CBCTs for all three periods. The term “virtual” when referring to sinus mucosa thickness and area was introduced because of the edema and bleeding that both contributed to a transient thickening and additional elevation of the sinus mucosa.

Results

The mean virtual thickness of the sinus mucosa was 2.7 ± 4.0 mm, 7.7 ± 7.1 mm, 1.7 ± 2.0 mm before surgery, and after 1 week and 9 months. The virtual mucosa area was 37.2 ± 52.5 mm², 184.5 ± 153.8 mm², and 34.0 ± 50.7 mm². The ostium diameter at the three periods evaluated was 1.8 ± 0.5 mm, 1.1 ± 0.6 mm, 1.5 ± 0.8 mm, respectively. Three infundibula (4.2%) were found out of patency before surgery while this number increased to 14 (19.4%) after 1 week. Nine months after surgery, only one infundibulum (1.4%) was out of patency, however, without presenting signs of sinus pathologies. The extension of the mucosal edema on the palatal sinus was reduced after 9 months of healing.

Conclusions

One week after sinus floor augmentation, the maxillary sinus mucosa increased in dimensions and in several cases involved the ostium, reducing its diameter and producing a transient loss of patency. After 9 months of healing, the initial conditions were recovered.

Sinus floor elevation or referral for further diagnosis and therapy: A comparison of maxillary sinus assessment by ENT specialists and dentists using cone beam computed tomography

OBJECTIVES

To compare ear, nose, and throat (ENT) specialists and dentists assessing health or pathology of maxillary sinuses using cone beam computed tomography (CBCT).

MATERIAL AND METHODS

Two ENT specialists and two oral surgeons assessed 100 CBCT datasets of healthy patients referred for dental implant placement in the posterior maxilla and decided on the possibility of sinus floor elevation or the necessity for further diagnostic examinations based solely on radiographic findings. Inter-rater agreements within the same specialty were calculated with Cohen's kappa and overall agreements with Fleiss kappa, and factors influencing the decisions taken were evaluated using regression analyses.

RESULTS

The correlation between all four raters was generally fair to moderate. The intra-specialty comparison showed a lower correlation between dentists than between ENT specialists. Absence of membrane thickening and total or subtotal sinus opacification showed the highest predictive value for a consensus in favor of sinus floor elevation and ENT referral, respectively. Flat membrane thickening with an irregular surface morphology was associated with disagreement between the examiners. Dome-shaped membrane thickenings were often considered as to be referred by dentists but not by ENTs.

CONCLUSION

The assessment of maxillary sinuses using CBCT imaging exhibited unsatisfactory agreement between ENT specialists and oral surgeons. Referral guidelines based on accidental CBCT findings that aim to diagnose relevant sinus pathologies early and avoid unnecessary diagnostics and/or therapies are needed, and an initial proposal for such recommendations is provided. Further research on correct interpretation of sinus findings and a validation of the present recommendations are required.

Frequency, location, and morphology of accessory maxillary sinus ostia: a retrospective study using cone beam computed tomography (CBCT)

PURPOSE

To evaluate the reliability of cone beam computed tomography (CBCT) imagining in the assessment of the frequency, location, and morphological characteristics of accessory maxillary ostia (AMOs), and to analyze a potential association with sinus and dentoalveolar pathologies.

METHODS

CBCT scans with bilateral maxillary sinuses that were acquired from September 2016 to September 2018 were initially screened. A total of 160 CBCT scans (320 sinuses) that fulfilled the inclusion criteria were included for further analysis. The presence, location, and morphological characteristics of the AMOs were evaluated in axial, coronal, and sagittal CBCT views. The findings were correlated with age, gender, sinus, and dentoalveolar pathology to assess for potential influencing factors on AMOs.

RESULTS

An AMO was present in 151 (47.2%) of the 320 sinuses. Most of the AMOs were located within the region of the nasal fontanelle or hiatus semilunaris (81.1%) presenting with an ovaloid (48.4%) or a round shape (39.0%). The average length of the AMOs was 2.33 ± 1.42 mm, occupying an area of 3.43 ± 4.51 mm², respectively. Morphological changes of the maxillary sinus mucosa were positively associated with length and area of AMOs. Furthermore, the status of the dentition in the posterior maxilla seemed to be an influencing factor on AMO shape.

CONCLUSIONS

Nearly half of the maxillary sinuses assessed in the present study population had an AMO. Pathologies of the maxillary sinus seem to have an impact on AMOs, which is demonstrated here by morphological changes of the sinus mucosa being associated with an increase in length and area of accessory ostia.