Prevalence and Location of Maxillary Sinus Septum and its Relation to Maxillary Sinusitis

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INTRODUCTION
Dental implant therapy has become a proven and predictable treatment modality providing both conservative and aesthetic alternative compared to conventional fixed and removable prostheses. 1 However, the possibility of implant therapy depends on the availability of bone at the surgical site.Implant placement in the posterior maxilla is especially complicated due to pneumatisation of the maxillary sinus leading to the reduced bone height of alveolar process. 2 The level of vertical bone height for implant placement may become deficient as it has individual variation. 3,4][10][11] Cone beam computed tomography (CBCT) guarantees images obtained in different planes, without superimpositions, with high quality, and excellent resolution, with relatively low dose of radiation making it the best choice for evaluating the maxillary sinuses. 12,13wever, there is limited data about prevalence of maxillary sinus septa and their relation to maxillary sinusitis.
Therefore, the purpose of the present study was to examine the prevalence and location of maxillary sinus septa and their relation to maxillary sinusitis using CBCT.

RESULTS
Of the 110 patients evaluated, 65 (59.09%) of them were  These surgeries are very sophisticated and may result in the rupture of the sinus membrane which may interfere with the physiology of the maxillary sinus.Furthermore, other anatomic characteristics, such as the presence of sinus septa may make this surgical technique even more complicated and results in the development of acute or chronic sinusitis and graft resorptions. 5rate of 22.8% sinus membrane perforations occurred, in the study done by Irinakis et al., 6 irrespective of whether there was a septum interfering in the region.Interference of septa in maxillary sinuses showed incidence of membrane perforation as 44.7%, with large perforations occurring in 26.3% and small perforations in 18.4% of the cases.
][10][11] In the present study, sinus septa were observed in 49.1% of the patients evaluated and 30.9% of the total sinuses had septa.5][16][17] However higher prevalence of maxillary sinus septa were reported by Zyl et al. 18 with the prevalence of 69% and lower prevalence of 9% were reported by a study done by Yang et al. 19 In the present study, the prevalence of septum is more in right side which is about 20.9%, which is similar to the finding of Koymen et al. 20 but it is higher on left side by a study done by Orhan et al. 12 and equal on right and left sinuses by a study done by Shen et al. 21 this study, there was no statistically significant association between gender and the presence of septa and its distribution.Other studies, however, showed that males had much more prevalence of sinus septa than females. 12,18,21,22e association was noted between sinusitis and the presence of septa and its distribution in the present study which was 54 (49.09%) who had septa had sinusitis which is statistically significant, this was inconsistent with a study done by Zhu et al., 23 and they have significant association between the absence of sinus septa and sinusitis.In another study, maxillary sinusitis was common in the presence of complete or incomplete sinus septa, 24 and this might be due to larger septa impeding proper drainage of the sinus.However further studies have to be done in larger populations to assess relationship between sinus septum and maxillary sinusitis.Statistically significant association was also noted between the presence of septum and the location in the arch with higher prevalence in the middle region of the maxillary sinus which is also seen in the majority of other studies in the literature. 6,8,12,25In the present study, of the total 54 sinuses where septa was present, only one septum was observed whereas Lee et al. 26 observed 24.5% of sinuses with one septum, 0.3% with two and Lee et al. 27 observed 28% of sinuses with one septum, 5% with two and 1% with three septa.
The high rate of prevalence of sinus septum in this study could be due to the accurate imaging technique, CBCT, as it represents one of the best techniques to evaluate the relevant anatomic variations for the cases of maxillary sinus surgeries.

CONCLUSION
analytical cross-sectional study was conducted at the Department of Periodontics and Department of Dr. Bhageshwar Dhami,1 Dr. Priti Shrestha,2 Dr. Ankit Saha,3 Dr. Nashib Pandey,1 Dr. Deepa Aryal 1 Dhami et al: Prevalence and Location of Maxillary Sinus Septum and its Relation to Maxillary Sinusitis Oral Medicine and Radiology, Kantipur Dental College, Basundhara, Kathmandu, Nepal.The study was conducted during July 2019 to June 2020 after getting approval from the Institutional Review Committee (Ref.8/19).Sample size was calculated using the following formula: Sample Size (n) = z 2 pq/e 2 .Where, z=1.96, p=0.071 (7.1%), 8 q=1-p=0.929,e=0.05(5%).Here, n = 101.3≈ 110.Thus, 110 subjects and 220 maxillary sinuses were evaluated for the study.Patient visiting the Department of Periodontics and Department of Oral Medicine and Radiology with age more than 15 years were included in the study by convenience sampling after they had signed an informed consent.The subjects excluded were; patients with craniofacial lesions or anomalies, with history of trauma and/or maxillofacial surgeries, patients who presented dental implants or bone grafts in the posterior region of the maxilla either or not associated with maxillary sinus augmentation surgeries.Cone beam computed tomography data were obtained from the CBCT images taken via CS9300 Care Stream, USA machine using the standardised protocol at 85 kV, 6.3 mA, Voxel size of 300x300x300 µm and the field of view was fixed at 17x13.5 cm.The data was then exported as Dicom Files and the CS Imaging site was used to visualise the radiographs in axial, coronal and sagittal views and measured using inbuilt measuring tools .The evaluations of maxillary sinus septum, prevalence, location, and maxillary sinusitis were done in axial, sagittal, cross-sectional, and reconstructed panoramic images with three-dimensional reconstructions (Figure 1).Each maxillary sinus bearing a septum was divided into three portions: anterior = mesial to distal aspect of second premolar; middle = distal aspect of second premolar to distal aspect of second molar; and posterior = distal aspect of second molar.Two examiners were trained individually with calibration exercises to identify and locate the sinus septum in the digital images of the CBCT scan.Each CBCT scan was analysed by these two examiners to confirm the presence or absence of sinus septum and location of sinus septum.Statistical analysis was done using SPSS version 20 (IBM Corp., Armonk, N.Y., USA).Association between age, gender and presence of sinus septa was calculated using Chi-square test.Statistical level was set at P <0.05 for significance.
Maxillary sinus septum in the present study was evaluated and was present in almost half of the subjects evaluated, the majorities were unilateral.Evaluation of maxillary sinus septum with the use of appropriate radiographic techniques is necessary to prevent possible complications during sinus surgery.Cone beam computed tomography is a powerful technique for the examination of maxillary sinus which represents three-dimentional representation of the region with minimum radiation.Presence and distribution of maxillary sinus septa is important in planning sinus surgeries and placement of implant in maxillary posterior region.

Table 1 :
Dhami et al: Prevalence and Location of Maxillary Sinus Septum and its Relation to Maxillary Sinusitis Distribution of sinus septum and its association with gender.
had mucosal thickening.Maxillary sinusitis involving both sinuses were present in 14 patients (12.73%), and 6 (5.45%) in right sinus and 11 (10%) in left sinus.In male subjects, 16 out of 54, (29.63%) had more maxillary septum in right sinus, whereas in female subjects, the number of sinus septum was found to be almost equal in right, left and both sinuses (Table1). of dental implants.In such areas, bone graft surgeries need to be done to place dental implants as short or extra short implants might not always serve the purpose for a long term success.Along with bone augmentation, posterior region of maxilla may need surgical procedures like direct

Table 2 :
Distribution of sinus septum and its association with maxillary sinusitis.

Table 3 :
Distribution of maxillary sinus septum and its association with its location.Dhami et al: Prevalence and Location of Maxillary Sinus Septum and its Relation to Maxillary Sinusitis and indirect sinus lift to elevate maxillary sinus floor.