Minimally Anterior Medial Maxillary Approach (MAMMA): a novel technique for a wide access to the maxillary sinus.

PURPOSE: To describe a novel endoscopic technique to approach the maxillary sinus (MS), the Modified Anterior Medial Maxillary Approach (MAMMA), preserving the inferior turbinate (IT) and the nasolacrimal duct (NLD). To perform radiological measurements and describe a case series to study the feasibility and limits of MAMMA. METHODS: Computed tomography (CT) scans (n = 150 nasal cavities) were used to calculate areas of the MAMMA to define surgical limits and extensions. Measurement of distances to critical anatomy landmarks and total area for the MAMMA were calculated. An instructional case illustrating the surgical technique and outcome was also included. RESULTS: Radiological analysis showed a mean distance from the Piriform Aperture (PA) to the anterior limit of the NLD of 1.03 ± 0.18 cm (range 0.59-1.48) and a mean distance from de PA to the posterior limit of the NLD of 1.57 ± 0.22 cm (range 1.02-2.11). The mean distance from the nasal floor to the Hasner's valve was 1.61 ± 0.27 cm (range 1.06-2.52) and the distance from the nasal floor to the insertion of the IT was 2.20 ± 0.36 cm (range 1.70-3.69). Finally, the mean total area for the MAMMA was 4.04 ± 0.52 cm2 (range 3.17-5.53). No complications or recurrence of the pathology were observed in operated patients. CONCLUSION: The MAMMA provides a wide surgical field of the MS walls comparable to more aggressive techniques, with preservation of the sinonasal and lacrimal function. MAMMA is an effective alternative to treat different MS pathologies including benign recurrent maxillary sinus tumors.

Sinus membrane thickness of healthy endodontically treated maxillary molars.

OBJECTIVE: The study aimed to investigate the sinus membrane thickness (SMT) adjacent to healthy endodontically-treated maxillary molars with or without protruded apical foramen into the sinus cavity using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: Images of 207 non-smoker patients aged 18-40 were retrospectively analyzed, 140 were endodontically treated, and 136 were without endodontic treatment. Patients with any sinus pathology, teeth that have symptoms, or poor root filling were excluded. Study groups consisted of Group EM-I (endodontically treated and protruded apical foramen), Group EM-C (endodontically treated and contacted apical foramen), and similarly without endodontic treatment; Group M-I and Group M-C. SMT upon the mesial, distal, and palatal roots was measured. One-way ANOVA and Student's t-tests were performed. RESULTS: Group EM-I had the thickest sinus membrane compared to other groups (p = 0.013). SMT values were 2.37-2.60 mm in Group EM-I, and 1.34-1.58 mm in other groups. Thickening (> 2 mm) percentages were 33.45% in Group EM-I and between 4.25 and 8.25% in other groups. No statistical difference was detected between first and second molars and genders (p > 0.05). CONCLUSION: When the apical foramen protruded into the sinus cavity, the conventional root canal treatment caused a minimal (between 2.37 mm and 2.60 mm) sinus membrane thickening with a rate of 33.45% based upon CBCT examinations.

Infraorbital canal variants and its clinical and surgical implications. A systematic review.

BACKGROUND: Recent literature highlights anomalous cranial nerves in the sinonasal region, notably in the sphenoid and maxillary sinuses, linked to anatomical factors. However, data on the suspended infraorbital canal (IOC) variant is scarce in cross-sectional imaging. Anatomical variations in the sphenoid sinuses, including optic, maxillary, and vidian nerves, raise interest among specialists involved in advanced sinonasal procedures. The infraorbital nerve's (ION) course along the orbital floor and its abnormal positioning within the orbital and maxillary sinus region pose risks of iatrogenic complications. A comprehensive radiological assessment is crucial before sinonasal surgeries. Cone-beam computed tomography (CBCT) is preferred for its spatial resolution and reduced radiation exposure. OBJECTIVE: The aim of this study was to describe the prevalence of anatomical variants of the infraorbital canal (IOC) and report its association with clinical condition or surgical implication. METHODS: We searched Medline, Scopus, Web of Science, Google Scholar, CINAHL, and LILACS databases from their inception up to June 2023. Two authors independently performed the search, study selection, data extraction, and assessed the methodological quality with assurance tool for anatomical studies (AQUA). Finally, the pooled prevalence was estimated using a random effects model. RESULTS: Preliminary results show that three types are prevalent, type 1: the IOC does not bulge into the maxillary sinus (MS); therefore, the infraorbital foramen through the anterior wall of MS could be used for identification of the ION. Type 2: the IOC divided the orbital floor into medial and lateral aspects. Type 3: the IOC hangs in the MS and the entire orbital floor lying above the IOC. From which the clinical implications where mainly surgical, in type 1 the infraorbital foramen through the anterior wall of MS could be used for identification of the ION, while in type 2, since the lateral orbital floor could not be directly accessed an inferiorly transposition of ION is helpful to expose the lateral orbital wall directly with a 0 scope; or using angled endoscopes and instruments, however, the authors opinion is that direct exposure potentially facilitates the visualization and management in complex situations such as residual or recurrent mass, foreign body, and fracture located at the lateral aspect of the canal. Lastly, in type 3, the ION it's easily exposed with a 0° scope. CONCLUSIONS: This systematic review identified four IOC variants: Type 1, within or below the MS roof; Type 2, partially protruding into the sinus; Type 3, fully protruding into the sinus or suspended from the roof; and Type 4, in the orbital floor. Clinical recommendations aim to prevent nerve injuries and enhance preoperative assessments. However, the lack of consistent statistical methods limits robust associations between IOC variants and clinical outcomes. Data heterogeneity and the absence of standardized reporting impede meta-analysis. Future research should prioritize detailed reporting, objective measurements, and statistical approaches for a comprehensive understanding of IOC variants and their clinical implications. Open Science Framework (OSF): https://doi.org/10.17605/OSF.IO/UGYFZ .

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.

Incidence of maxillary sinus septa in the saudi population.

BACKGROUND: The variability in the maxillary sinus anatomy makes dental implant planning challenging. One of the anatomical landmarks that could affect the decision for implant placement around the maxillary sinus is the sinus septa. This study aimed to retrospectively determine the prevalence, anatomical distribution, and morphology of the maxillary sinus septa. MATERIALS AND METHODS: This study included 309 CBCT images that were analyzed to determine the prevalence, height, location, and orientation of the maxillary sinus septa. Descriptive statistics, Mann‒Whitney U tests, and Kruskal‒Wallis tests were used for data analysis. RESULTS: A total of 618 maxillary sinuses were analyzed. Maxillary septa were present in 30% (n = 188) of the sinuses and in approximately 45% of the analyzed images. The mean height of the septa was 5.09 mm. The presence of bilateral septa was evident in 49 subjects (35.25%). Female subjects were significantly more likely to have only one septum (n = 67, 53.6%, p < 0.05). CONCLUSION: The presence of septa is very common, found in one-third to approximately half of the evaluated cases, which warrants careful examination before any surgical interventions to avoid possible complications.

Does the floor of the maxillary sinus affect tooth movement for premolar extraction space closure?

OBJECTIVE: The study investigated orthodontic tooth movement by comparing various horizontal and angular measures of the teeth having different sinus-root relationship (SRR) of patients undergoing first premolar extraction treatment protocols. MATERIALS AND METHODS: This retrospective cross-sectional study included 45 Taiwanese adult patients, classified as the control group (n = 15) and the sinus group (n = 30) according to SRR. The control group had type I SRR (sinus floor above the level connecting the buccal and palatal root apices), whereas the sinus group included patients with type V SRR (the buccal and palatal root displayed apical protrusion into the sinus floor). Morphology was identified using pretreatment orthopantomograms. Lateral cephalometric measurements were conducted before treatment (T1) and at debonding (T2). RESULTS: Post debonding, there were no statistically significant difference in the two groups. However, the incisors in the control group became marginally more upright than those of the sinus group, and the molars demonstrated tipping movement with minimal anchorage loss in the sinus group than in the control group. The total treatment time was not significantly different between the 2 groups. CONCLUSION: The study revealed that the sinus-root relationship does not affect the orthodontic tooth movement. However, a more extensive 3-D study with larger sample size is strongly recommended before coming to any conclusion. CLINICAL RELEVANCE: The lining of the floor of the maxillary sinus does not affect the orthodontic tooth movement.

Assessment of the prelacrimal recess in different maxillary sinus pneumatizations in relation to endoscopic prelacrimal recess approaches: a computed tomography study.

PURPOSE: To assist in planning before the endoscopic prelacrimal recess (PLR) approach, we aimed to investigate the relationship between morphometry and variations of PLR in maxillary sinus (MS) pneumatizations. METHODS: Retrospective analysis of the paranasal sinus computed tomography images of 150 patients was conducted to determine the pneumatization patterns of the MS, PLR variations, and the applicability of the PLR approach. The results were compared based on lateralization, gender, and age groups. RESULTS: The PLRwidth, the anteroposterior diameter of the nasolacrimal duct (NLD), the vertical and horizontal diameters of the MS were the highest in hyperplasic MS, and decreased significantly with increasing age (p = 0.005, p = 0.017, p = 0.000), respectively. Most of the morphometric measurements were higher in hyperplasic MS, while the medial wall thickness of PLR was higher in hypoplasic MS. The PLRwidth for feasibility of the PLR approach were Type I (48%) in hypoplasic MS and Type III (80%) in hyperplasic MS (p < 0.001), respectively. The PLR medial wall thickness was higher in Type I, while the piriform aperture angle (PAA), MS volume, length, and slope of the NLD were higher in Type III PLRwidth (p = 0.000), respectively. The highest anterior and separation-type variations of the PLR were observed in hyperplasic MS, whereas 31.0% of hypoplasic MS had no PLR (p < 0.001). CONCLUSION: This study revealed that PLRwidth and PAA were the highest in hyperplasic MS, which allows the endoscopic PLR approach to be performed more easily. For safer and uncomplicated surgery, surgeon should be aware of the PLR anatomy in different MS pneumatization patterns.

Cone-beam computed tomographic analysis of maxillary sinus septa among Yemeni population: a cross-sectional study.

BACKGROUND: Maxillary sinus septa increase perforation risk of Schneiderian membrane during the sinus floor elevation (SFE). Cone Beam Computed Tomography (CBCT) allows for a more precise assessment of the septal position; thus, preoperative CBCT analysis is substantial to avoid possible complications. This study aims to investigate the 3D characteristics of the maxillary sinus septa based on CBCT images. To our knowledge, no study reported the CBCT-based investigation for the sinus septa among Yemeni population. MATERIALS AND METHODS: This is a retrospective cross-sectional analysis of 880 sinus CBCT images 440 patients. The septa prevalence, locations, orientations, morphology, and associated factors were analyzed. The effect of age, gender, and dental status on the sinus septa and the relationship between sinus membrane pathology and sinus septa were also analyzed. Anatomage (Invivo version 6) was used for CBCT images analysis. Descriptive and analytical statistics were performed, and a P-value < 0.05 was significantly considered. RESULTS: The maxillary sinus septa were found among 63.9% of patients and 47% of sinuses. The average septa height was 5.2 mm. 15.7% of patients had septa in the right maxilla, 18% in the left, and 30.2% in both. Gender, age, and dental condition had no influence on the presence of septa, and septa presence did not influence sinus membrane pathology. Many septa originated from the floor (54.5%), located in the middle (43%), with coronal orientation (66%) and complete configuration (58.2%). CONCLUSION: Based on our findings, the septa prevalence, locations, orientations, and morphology were significant and equivalent to the highest recorded in the literature yet. Thus, when sinus floor elevation is planned, CBCT imaging of the maxillary sinus is recommended for safe dental implantation.

Comparison of biological and mechanical properties of different paranasal sinus mucosa in goat.

OBJECTIVE: The present study was designed to explore endurable pressure intensity of different paranasal sinus mucosa in goats. METHOD: Mucosa commonly involved in maxillary sinus augmentation, including mucosa from maxillary sinus crest, maxillary sinus floor, and frontal sinus, were harvested in a computed tomography-guided manner. The obtained mucosa was then sectioned into square and irregular ones for maximum endurable pressure intensity determination and morphological observation, respectively. RESULTS: Thickness of paranasal sinus mucosa, as determined under morphological staining by an optical microscope with a graduated eyepiece, were calculated. And the results showed that the average thickness of maxillary sinus crest mucosa, floor mucosa, and frontal sinus mucosa in goats were 410.03 ± 65.97 µm, 461.33 ± 91.37 µm and 216.90 ± 46.47 µm, respectively. Significant differences between maxillary sinus crest and frontal sinus, maxillary sinus floor, and frontal sinus were observed (P < 0.05). Maximum endurable pressure intensity was determined by utilizing a self-made clamp device and the results revealed maximum endurable pressure intensity of maxillary sinus crest mucosa, floor mucosa and frontal sinus mucosa in goats were 260.08 ± 80.12Kpa, 306.90 ± 94.37Kpa and 121.72 ± 31.72Kpa, respectively. Also, a statistically significant difference was observed when comparing the endurable pressure intensity between maxillary sinus crest and frontal sinus, maxillary sinus floor, and frontal sinus (P < 0.05). Further correlation analysis also revealed a positive correlation between the thickness of mucosa of the maxillary sinus and frontal sinus and maximum endurable pressure intensity (P < 0.05). CONCLUSION: Mucosal thickness and maximum endurable pressure intensity of maxillary sinus crest and floor were larger than that of frontal sinus mucosa and a positive correlation between the thickness of mucosa and endurable pressure intensity was observed. Our results thus might provide an experimental basis and guidance for mucosa-related problems involved maxillary sinus augmentation.

Anatomical Changes in a Case with Asymmetrical Bilateral Maxillary Sinus Hypoplasia.

Background and Objectives: The maxillary sinus hypoplasia (MSH) is an occasional variation of the maxilla, occurring either unilaterally or bilaterally. Previous studies dealing with MSH have not detailed the consequent anatomical changes of the maxilla and adjacent fossae. Materials and Methods: A 58-year-old female case was scanned in Cone Beam Computed Tomography and found to have asymmetrical bilateral MSH, who was then further evaluated anatomically. Results: The maxillary sinuses were hypoplastic and had mild mucosal thickenings. The orbital floors were curved. The uncinate process and the ethmoidal infundibulum were laterally displaced beneath the orbit floor. On each side, the lateral nasal wall protruded within the respective maxillary bone to reach above the vestibular cortical plate of the alveolar process. This expansion of the lateral nasal walls was limited to the premolar and first molar regions. The inferior turbinates were laterally curved. The perpendicular palatine plate was building a postero-lateral nasal wall in front of the pterygopalatine fossa. Conclusions: The classification systems of MSH should be detailed to indicate whether the normal uncinate process is medial or inferior to the orbit. The lateral expansion of the lateral nasal wall in MSH is limited to the anterior part of that wall. The laterally expanded nasal fossa could reach anterior to the pterygopalatine fossa in MSH. Seemingly, CBCT is a better tool than CT to evaluate the detailed anatomy of the modified anatomical structures in MSH; as such, it could be of help in a surgical approach.

Surgical anatomy and nuances of the expanded transpterygoid approach to the pterygopalatine fossa and upper parapharyngeal space: a stepwise cadaveric dissection.

BACKGROUND: Superb knowledge of anatomy and techniques to remove the natural barriers preventing full access to the most lateral aspect of the skull base determines the ease of using the transpterygoid approach (ETPA) as the main gateway for all the coronal planes during endonasal surgeries. METHODS: Throughout stepwise image-guided cadaveric dissections, we describe the surgical anatomy and nuances of the ETPA to the pterygopalatine fossa (PPF) and upper parapharyngeal space (UPPS). CONCLUSION: The ETPA represents a lateral extension of the midline corridor and provides a valuable route to access the PPF/UPPS. Major landmarks for this EEA are the infraorbital canal, sphenopalatine foramen, and vidian nerve. It comprises the removal of the palatine bone, posterior wall of the maxillary sinus, and PPF transposition to drill the pterygoid process.

Three-dimensional visualization of the alveolar bone and posterior superior alveolar foramen in gender.

The present study applied a three-dimensional (3D) program to measure the distances from the maxillary sinus floor (MSF) to the lingual and buccal alveolar bone and also to the posterior superior alveolar foramen (PSAF), with the aim of determining differences according to gender. The study also attempted to verify the accuracy of measurements obtained from 3D images by performing comparisons with the results obtained in a preliminary study. The results showed that the alveolar bone length and the MAF-PSAF were generally larger in males than in females. It is also predicted that the accuracy of data obtained from a 3D program will be higher than that of data derived from conventional two-dimensional (2D) images. The accurate measurements obtained in this study are anticipated to prove useful in assessments related to dental implantation and anatomical structures. The fundamental data obtained in this study may also assist in setting the goals of future studies utilizing 3D programs.

A morphometric analysis of the immature human infraorbital canal.

PURPOSE: The importance of the infraorbital canal in the growth of the maxilla and associated mid-facial region has significance for innervation of this region as well as the associated dentition, yet little is known about the development of the canal. An analysis of its dimensions and morphology during the late prenatal and early postnatal periods was thus undertaken. The aim of this study was to describe changes in the morphology, size and branching pattern of the infraorbital canal during the late prenatal and early postnatal stages of human growth. METHODS: Fifty human fetal and neonatal maxillae were analyzed. The sample included 27 late prenatal individuals (30 gestational weeks and birth) and 23 early postnatal individuals (birth and 1 year). Maxillae were scanned using a Nikon XTH 225 L micro-CT unit and analyzed using VG studiomax v3.2. Measurements included the maximum width, height and surface area of each foramen associated with the infraorbital canal and the total length of the canal, bilaterally. RESULTS: All the measurements of the canal were greater in the early postnatal group than in the late prenatal group, while the walls and branching pattern of the canal were better developed in the postnatal group. Bone development occurred within the walls as development proceeded. Variations in the branching pattern of the canal were found. CONCLUSION: The morphology of the infraorbital canal reflected the developmental stage of associated structures such as the dentition, maxillary sinus and orbit.

Complications in sinus lift.

Prosthetic rehabilitation of atrophic maxillary implants often requires grafting owing to vertical and transversal bone deficiency. The use of this procedure in order to insert implants was introduced by Tatum and published as a clinical study by Boyne and James. It can be performed via a lateral or crestal approach. This surgery is now widespread, with good results in terms of bone augmentation and implant osseointegration. Nevertheless, there is a small proportion of patients who have infectious complications with an incidence ranging from 3.5% to 10.5%. We observe that maxillary sinus augmentation is a successful preprosthetic technique for augmentation of the edentulous posterior maxilla. Preoperative assessment of the anatomy of the sinus reduces the rate of complications considerably.

Assessment of the prelacrimal recess in maxillary sinus in different sex and age groups using cone beam computed tomography (CBCT).

BACKGROUND: The intranasal endoscopic prelacrimal recess approach (PLRA) to the maxillary sinus (MS) has been reported to treat many MS and skull base diseases. However, previous studies revealed that the width of the prelacrimal recess (PLR) shows a large individual variation. The purpose of this study was to ascertain the prevalence of the PLR in MS according to gender and age. METHODS: A series of 701 maxillofacial cone beam computed tomography (CBCT) scans from adult patients were analyzed retrospectively. Patients were divided into five age groups (18-24 years, 25-34 years, 35-44 years, 45-54 years, and ≥ 55 years) and by sex. The frequencies of occurrence of the PLR in the MS were calculated and compared. RESULTS: According to the findings obtained from our study, PLR was present in 81.5% of maxillary sinuses. No differences were found when the data distributions of right and left sides were compared. For individuals, the right and left sides were not always symmetrical. The probability of PLR was lesser among women than among men, but this differences was not significant. Another finding of our study was that the percentage of PLR decreased with increasing age among patients aged < 55 years, however, increased again among patients aged ≥ 55 years. CONCLUSION: The anatomy of PLR varies among individuals. Careful analysis of individual anatomical structure characteristic is recommended when considering intranasal endoscopic PLRA to the MS. Besides, the age variation of PLR should be considered in order to avoid complications.

Endoscopic transnasal transmaxillary approach to the upper parapharyngeal space and the skull base.

PURPOSE: Treatment of tumors arising in the upper parapharyngeal space (PPS) or the floor of the middle cranial fossa is challenging. This study aims to present anatomical landmarks for a combined endoscopic transnasal and anterior transmaxillary approach to the upper PPS and the floor of the middle cranial fossa and to further evaluate their clinical application. METHODS: Dissection of the upper PPS using a combined endoscopic endonasal transpterygoid and anterior transmaxillary approach was performed in six cadaveric heads. Surgical landmarks associated with the approach were defined. The defined approach was applied in patients with tumors involving the upper PPS. RESULTS: The medial pterygoid muscle, tensor veli palatini muscle and levator veli palatini muscle were key landmarks of the approach into the upper PPS. The lateral pterygoid plate, foramen ovale and mandibular nerve were important anatomical landmarks for exposing the parapharyngeal segment of the internal carotid artery through a combined endoscopic transnasal and anterior transmaxillary approach. The combined approach provided a better view of the upper PPS and middle skull base, allowing for effective bimanual techniques and bleeding control. Application of the anterior transmaxillary approach also provided a better view of the inferior limits of the upper PPS and facilitated control of the internal carotid artery. CONCLUSIONS: Improving the knowledge of the endoscopic anatomy of the upper PPS allowed us to achieve an optimal approach to tumors arising in the upper PPS. The combined endoscopic transnasal and anterior transmaxillary approach is a minimally invasive alternative approach to the upper PPS.

Canalis sinuosus: anatomical variation or structure?

PURPOSE: The main goal of the present study was to verify the presence, spatial location, the end of the canalis sinuosus (CS) trajectory and size of CS using cone beam computed tomography (CBCT) to characterise it as either a structure or an anatomical variation. METHODS: A trained examiner specialist in dental radiology and imagenology selected 200 CBCT images of the maxilla from 107 (53.5%) female and 93 (46.5%) male individuals aged between 18 and 85 years. RESULTS: A total of 133 (66.5%) patients had CS, being 61 (45.86%) unilateral and 72 (54.14%) bilateral. A higher frequency of CS was observed in males (P < 0.05) and no relationship was found between its presence and age. The end of the CS trajectory was more frequent in the regions of central incisor (n = 91; 44.39%), followed by lateral incisor (n = 45; 21.95%) and canine (n = 29; 14.15%). In our sample, the majority of these canals had a diameter of up to 1 mm (n = 198/205; 96.6%). No statistically significant relationship between diameter and the end of the CS trajectory, with location (i.e. bilateral or unilateral) was found. Gender and age had no influence on diameter, spatial location and the end of the CS trajectory (P > 0.05%). CONCLUSION: As CS was frequently found in our sample, it can be considered an anatomical structure, and as such, it is fundamental that the dentist requests a CBCT examination before performing any invasive procedure in the maxillary region to preserve this important structure.

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.

Evaluation of the Relationship of Dimensions of Maxillary Sinus Drainage System with Anatomical Variations and Sinusopathy: Cone-Beam Computed Tomography Findings.

OBJECTIVE: The aim of this study was to evaluate the correlation between the length of the infundibulum and ostium height with the anatomic variations of osteomeatal complex (OMC) and sinus pathology using cone-beam computed tomography (CBCT). METHODS: CBCT images of 204 patients (408 maxillary sinuses) were evaluated retrospectively. The height of the ostium and the length of the infundibulum were measured. The presence of maxillary sinus pathology, nasal septal deviation, Haller cells, concha bullosa, and sinus septa were analyzed. The correlation between the size of the maxillary sinus drainage system and anatomic variations was compared using the t test, Fisher's exact test, and χ2 test. The effect of tooth loss on the length of the infundibulum and ostium height was also analyzed using ANOVA. RESULTS: The height of the ostium and the maximal septal deviation angle were found to be significantly greater in males (p < 0.05). As ostium height increased, the presence of maxillary sinus septa increased (p < 0.05). No statistically significant association was detected between other variations and the length of infundibulum or ostium height. The relationship between tooth loss and both the length of the infundibulum and ostium height were found to be insignificant (p > 0.05). CONCLUSIONS: Radiographic examination, especially on CBCT images, is important for an evaluation of maxillary sinuses. here, we demonstrated a significant relationship between ostium height and the presence of maxillary sinus septa. However, it was found that nasal septal deviation, concha bullosa, Haller cells, and other sinusopathies did not have a major effect on the size of the maxillary sinus drainage system.

[Function and physiology of the maxillary sinus]. / Funktion und Physiologie der Kieferhöhle.

BACKGROUND: The question of the "true" function of the maxillary sinus and the paranasal sinuses (PS) has been a controversial issue in the literature for decades, leading to many discussions and speculations. OBJECTIVE: This review briefly summarizes various theories on the possible physiology and functions of the maxillary sinus/PS that have been discussed over the centuries. MATERIALS AND METHODS: A literature search was conducted in PubMed using a combination of the search terms "physiology," "function," "maxillary sinus," and "paranasal sinuses." RESULTS: Current and scientifically evidenced theories are described. "Sinusology" is the science of the PS. The maxillary sinuses might simply serve to improve the respiratory function of the nose. A flow of inspiratory air does not occur. The maxillary sinuses are decisively involved in the production of nitrogen monoxide (NO) and thus in supporting the immune defense of the nasal cavity. The mucosa of the maxillary sinus continuously synthesizes NO and serves as a reservoir of NO. Other important functions are protection of the orbit and the brain in case of skull fractures, as well as weight reduction of the skull. CONCLUSION: The various theories about the function of the PS still raise many questions and their true function is yet not fully understood. Possible functions of the maxillary sinuses are local immune defense through the production of NO. The PS serve as a crumple zone for vital cerebral structures in the context of craniocerebral traumas.