Maxillary Sinus Septa: Prevalence and Variation with Gender and Location

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INTRODUCTION
Maxillary sinus septa are the barriers of cortical bone that divide the maxillary sinus floor into multiple compartments, known as recesses. 1The role of the septum is to separate the sinus into two or more antra and to strengthen the bony structure of the sinus. 2 The presence and dimension of maxillary septa are of practical relevance to periodontists, oral and maxillofacial surgeons as well as otolaryngologists. 3 relevance to the placement of implants, septa seen in the floor of the sinus or along the lateral wall can interfere with its placement either directly by being present in its area of placement or indirectly by hindering the elevation of the wall during lateral sinus approach. 4The prevalence of mul-

RESULTS
The    The prevalence of uniseptate septa were greater than multiseptate septa being 184 (92.93%) and 14 (7.07%) respectively.The total number of septa in the present study was found to of 211.The highest number of septa were located in the middle region extending from distal aspect of second premolar to mesial aspect of second molar (157, 74.41%) followed by anterior region which is mesial from middle region (52, 24.64%) and posterior region which is distal to second molar (2, 0.95%, Figure 2).

DISCUSSION
Maxillary sinus was first analysed by Underwood AS for its characteristics and presence of septa, thus it is also referred as Underwood's septa. 7Underwood reported that the septa are formed because of the different eruption phases of the teeth. 7Structurally, they have been described as inverted gothic arches arising from the inferior and lateral walls of the sinus and coming to a sharp edge along its most apical border; they can divide the sinus into two or more compartments. 8Neivert and Harry proposed that the septa are derived from the fingerlike projections produced by the embryologic out-pouching of the ethmoid infundibulum, where the contiguous walls do not absorb. 9Vinter et al.
observed that resorption of the maxillary alveolar process proceeds irregularly in different regions leaving bony crests on the sinus floor. 10ennmair et al. (1999) proposed a classification of congenital and acquired septa into primary septa, which can develop in all regions of the maxillary sinus, and arise during development of the maxilla, and secondary septa, which arise from irregular pneumatization of the sinus floor following tooth loss. 11However, the exact mechanism responsible for maxillary septum development is still unclear, although a role for the irregular pneumatization of the sinus floor following tooth loss has been suggested. 5e present study observed the maxillary sinus septa in panoramic radiographs.This method is the most commonly used diagnostic aid in pre-operative sinus evaluation, and is affordable. 12The result showed that the septa were more prevalent in males.Furthermore, the unilateral septa were more prevalent in male.These findings were statistically significant.Similar observations were reported in other studies. 2,5,13,14However, female prevalence have been observed. 2,15The mean maximum bite force in males was observed to be significantly higher than in females, which could explain the difference in septa prevalence based on gender. 16e right maxilla showed greater prevalence of septa as compared to the left side (57.73% and 42.27% respectively).
Other studies also showed the greater presence of septa in the right side than on the left. 4,6Park et al. 2 observed a greater prevalence on the left side.However, their finding was not statistically significant.
Septa are classified under headings such as septa location, morphology, and orientation.When septa are evaluated in terms of location, anterior septa exist between the first and second premolar region (sinus anterior wall) and the mesial of the first molar.Middle region septa exist between the mesial of the first molar and the mesial of the second molar.
Posterior septa are between the distal of the second molar and the posterior sinus wall. 17The present study showed that the highest number of septa was present on the middle region followed by anterior and posterior region (74.41%,24.64% and 0.95% respectively).Similar prevalence of septa on the middle region were revealed by few other studies 2,5,14 whilst few studies reported anterior septa being more prevalent. 18,191][22] Alurt et al. 20 observed posterior prevalence in both CBCT (cone-beam computed tomography) and panoramic radiograph.
Owing to the increase in sinus floor elevation procedures by general practitioners, more complications of sinus floor elevation are seen.This is probably due to the lack of formal training or inadequate training for performing this type of surgery and ignorance about the anatomy of the maxillary sinus.This emphasises need for studies related to the maxillary sinus.The perforation of the Schneiderian membrane has been reported to be as high as 44%. 23,24One of the possible causes of such a high perforation rate of the Schneiderian membrane during sinus floor elevation is the presence of septa. 24Presence of septa in the floor of the sinus or along the lateral wall, can interfere with the placement of an implant either directly by being present in its area of placement or indirectly by hindering the elevation of the wall during lateral sinus approach. 4NCLUSION Septa in the maxillary sinus was more prevalent amongst males.Unilateral presentation of septa was prevalent than bilateral.This signifies practitioner to be cautious during treatment involving the maxillary sinus; specially on the right side.However, further studies based on other imaging modalities as well as clinical correlation is needed for supporting the findings.
An analytical cross-sectional observational study was carried out in the Department of Periodontics, Kantipur Dental College Teaching Hospital and Research Centre after ethical approval from the institution.The study was carried out for a period of three months.The sample size of 433 was obtained using the formula: sample size Z= z deviate corresponding to desired reliability level (at 95%, 1.96) Correspondence Dr. Kamana Neupane Email: drkneupane@gmail.comCitation Neupane K, Dhami M, Pandey N, Aryal D, Koju S, Maharjan N. Maxillary Sinus Septa: Prevalence and Variation with Gender and Location.J Nepal Soc Perio Oral Implantol.2021 Jul-Dec;5(10):82-6 e = precision level = 0.04 p= proportion in the target population = 0.236 6 q= 1-p (proportion in the target population) = 0.764 The study constituted of good quality standard panoramic radiographs with clearly visible maxillary sinus of patients who had full complement of teeth taken as part of pretreatment planning or oral diagnosis.Each patient was exposed to panoramic X-ray by Carestream (CS9300, Kodak) at 74kv, 12 mA for 14.3 seconds exposure time with head positioning according to the manufacturer's specified position.Radiographs of patients with evidence of previous intrusion procedure of sinus, any pathological or developmental changes in maxillary sinus, poor quality radiographs lacking adequate contrast, distorted images and unclear radiographs were excluded.Orthopantomograms (OPGs) which fulfilled the inclusion criteria of the study were taken and were observed by single examiner for the presence of septa in the maxillary sinus.Presence or absence of septa were noted along with their position and site (Figure 1).Demographic details like age and gender were noted.Data were compiled and analysed using Statistical package for the Social Sciences (SPSS) software version 21 (IBM Corp., Armonk, N.Y., USA).Descriptive analysis was performed.Chi-Square test was applied to check the association between gender and presence of septa and site.P value < 0.05 was taken as statistically significant.

Figure 2 :
Figure 2: Bar diagram showing frequency distribution of prevalence of maxillary sinus septa based on the location.