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 Table of Contents  
Year : 2021  |  Volume : 33  |  Issue : 3  |  Page : 260-265

Hidden pathologies of maxillary sinus using CBCT scans

Department of Oral Medicine and Radiology, Sardar Patel Post Graduate Institute of Dental and Medical Sciences, Lucknow, Uttar Pradesh, India

Date of Submission04-Feb-2021
Date of Decision03-Jun-2021
Date of Acceptance04-Jun-2021
Date of Web Publication28-Sep-2021

Correspondence Address:
Dr. Md Sanaullah
Quazi Tola Arrah Bhojpur, Bihar
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jiaomr.jiaomr_36_21

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Introduction: Diagnosis of orofacial pathologies is difficult with the 2 dimensional (2D) images taken from conventional radiography. Cone-beam computed tomography (CBCT) has been developed with 3 dimensional (3D) modalities and has become a better alternative to conventional radiography. Highre solution axial, coronal, and sagittal sections are the most revealing, noninvasive techniques for assessing the maxillary sinus anatomical variations, pathology, and its adjacent structures and areas. Aim: This study aimed to analyze the prevalence of pathological changes in the maxillary sinus of asymptomatic cases using CBCT for diagnostic purposes. Materials and Methods: This study was evaluated among 200 patients for hidden pathologies in the maxillary sinus. Pathological findings were categorized as a mucosal thickening, polypoid mucosal thickening, radiopacification, and no pathological findings. Results: In the present study, the overall prevalence of the mucous retention cyst was found to be 30.25%, the polyp was 4.25%, the mucocele was 0.50%, and the overall mucosal thickenings was 35%. Conclusions: In our study, the mucosal thickening has a very high rate of incidental maxillary sinus pathologies in asymptomatic patients. Therefore, a detailed three-dimensional imaging using CBCT is stated in most patients for proper treatment planning. A careful review of the entire CBCT scans is essential to avoid under-or overestimation of potential complications in providing comprehensive health care.

Keywords: CBCT Scans, incidental pathologies, maxillary sinus

How to cite this article:
Sanaullah M, Sinha A, Srivastava S, Mishra A, Singh Y, Basu S. Hidden pathologies of maxillary sinus using CBCT scans. J Indian Acad Oral Med Radiol 2021;33:260-5

How to cite this URL:
Sanaullah M, Sinha A, Srivastava S, Mishra A, Singh Y, Basu S. Hidden pathologies of maxillary sinus using CBCT scans. J Indian Acad Oral Med Radiol [serial online] 2021 [cited 2023 Feb 8];33:260-5. Available from: http://www.jiaomr.in/text.asp?2021/33/3/260/326885

   Introduction Top

Four paired sets of air-filled craniofacial complex cavities reflect the paranasal sinuses.[1] They are called maxillary, ethmoid, sphenoid, and frontal according to their place in the facial structures.[2] There is a biphasic development in the maxillary sinus, also called the maxillary antra or Highmore's antrum. In the first 3 years of life, there is the first stage of development, followed by a second cycle between the ages of 7 and 18.[2] The maxillary sinus, via a posterior-superior natural ostium, situated on the medial surface, communicates with the homolateral nasal fossa. The physiology of the natural maxillary sinus highly depends on the proper function of both the maxillary sinus ostium and the mucosal lining.[1]

Underwood was the first to describe the maxillary sinus septa within the maxillary sinus as cortical bone walls, its shape has been described as an inverted Gothic arch originating from the inferior or lateral walls of the sinus, and may even split into two or more cavities of the sinus. Due to their production at three distinct moments of tooth eruption, the position of the septa within is replicated in various individuals.[1] There is a major difference between dentulous and edentulous individuals in the bone height of the sinus floor. Sinus anatomical variations, such as septa and sinus floor mucosal thickening raise the risk of sinus membrane perforation in the posterior maxilla during pre-implant surgery.[3] Failure to identify incidental anomalies is associated with oral radiologists' limited capacity and experience in the analysis of volumetric images and negligence in the systematic visual inspection of the entire image, including the dentoalveolar region and all adjacent maxilla-mandibular complex structures.[4] Pathologies of maxillary sinuses include the so-called intrinsic (originating primarily from within the sinus walls) and extrinsic (those that originate outside the sinuses or, those which either impinge on or, infiltrate the sinuses) diseases such as mucosal thickening (MT), polypoidal mucosal thickening (PMT), partial opacification with liquid accumulation (PO), complete opacification (CO), and many other findings as retention cysts, root stumps, impacted teeth, antroliths, exostosis, oro-antral fistulas, and a plethora of benign and malignant diseases and further abnormalities.[5] In the diagnosis of orofacial pathology and subsequent treatment preparation, dental radiography provides important details. With the 2D images obtained from traditional radiography, diagnosis of orofacial pathology is difficult. With 3D modalities, cone-beam computed tomography (CBCT) has become a better alternative to traditional radiography. For imaging the craniofacial region, CBCT is well suited. It offers consistent images of strongly contrasting structures and is extremely helpful for bone evaluation.[7] The operator also finds accidental findings in the maxillary sinus region.[6]

CBCT can reliably record, view, and provide maxillofacial anatomy and pathology with 3-dimensional visualization.[7] It is important to study the maxillary sinus by CBCT as it has become the standard imaging modality for visualizing the maxillary sinus because of its ability to visualize both bone and soft tissue in multiple views with thin sectioning, having both axial and coronal views which allow the clinician to assess the relationship of a periapical lesion to a sinus floor defect and any resultant changes in the soft tissue of the sinus.[8]

In the maxillary sinus floor elevation procedure, to reduce the risk of postoperative complications, it is important to be familiar with various anatomical and pathological findings in the sinus.[7]

CBCT scans that do not involve ostium, infundibulum, and ethmoid cells do not allow the maxillary sinus drainage system to be examined, and protecting the planned procedure cannot be predicted by the dental surgeon. Dentists typically presume natural sinus function and continue with their surgical plan when the demonstrated lower portion of the maxillary sinus is completely aerated. It is, therefore, essential to examine sinus anatomy, including the osteomeatal complex, completely.[9]

The anatomical variance and incidental maxillary sinus pathologies seen in CBCT scans were, therefore, expected to be determined by this research, as it offers diagnostic information that is important for clinical decision-making, better care planning, and predictable results.[1]

   Materials and Methods Top

This retrospective study was conducted in the Department of Oral Medicine and Radiology of a Dental college for a period of 1 year and 9 months. 200 subjects (400 maxillary sinuses) were included in this study for hidden pathologies in the maxillary sinus. Approval for this study was obtained from the Institutional Review Board with vide letter no. OMR/02/121819/IEC, Dated 11/01/2019. The declaration of Helsinki (1964) was taken into consideration, and written informed consent was taken. The cases were selected based on the following criteria.

A. Inclusion criteria:

  • Subjects aged between 13 and 80 years.
  • Patients who are advised CBCT for: Assessment of rampant caries, wasting disease, etc.
  • Assessment of sinuses (frontal, ethmoidal, maxillary, sphenoidal)
  • Implant planning
  • Orthodontic management
  • Full mouth rehabilitation
  • Periodontal evaluation
  • Patient with asymptomatic maxillary pathology.

B. Exclusion criteria:

  • Patients below 13 years of age and above 80 years of age.
  • Patients with maxillofacial trauma involving maxillary sinus.
  • Patients with known pathology involving maxillary sinus.
  • Completely edentulous patients who are completely edentulous.
  • Patients who are suspected of having carcinoma.
  • Patients suspected of having cysts in the maxillary region.
  • Images of low-resolution quality.
  • Metallic artifacts that impair sinus visualization.

The maxillofacial CBCT examination was performed using i-CAT [Figure 1] cone-beam computed tomography (Imaging Sciences International, Hatfield, PA, USA) with tomography specifications of tube potential (Kv) 120, current (mA) 5, Voxel size (mm) 0.3, and scan time (s) 20–40. Image analysis was performed using the i-CAT Vision Software, employing the multi-planar reconstruction (MPR) window in which axial, coronal, and sagittal planes were visualized in 0.3 mm intervals, and CBCT images were viewed using in vivo 3D software giving multiplanar reformation. Pathological findings of the maxillary sinus were obtained by CBCT scans and evaluated in all three planes (axial, coronal, sagittal). Pathological findings were categorized as mucosal thickening [Figure 2], polypoid mucosal thickening [Figure 3], and radiopacification [Figure 4], and any other. Mucosal thickening was evaluated by measuring the distance between the air mucosal surface and the inner bony margins of the sinus. Pathologies were considered when the mucosal thickening was over 2 mm. Polyps [Figure 5] and retention cysts were smooth, outwardly convex, soft-tissue masses as seen in imaging (CT, MRI) and could not be differentiated. Hence, both were included in the polypoid thickening. Mucocele represented complete opacification, and the margins were expanded and usually thinned. Radiopacification was evaluated in cases having chronic sinusitis. All scans were reviewed by three investigators who were not blinded, questionable results were examined with a consulting oral and maxillofacial radiologist, and no consensus was observed.
Figure 1: I cat CBCT machine

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Figure 2: Mucosal thickening on (Coronal view)

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Figure 3: Polypoidal mucosal thickening on (sagittal view)

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Figure 4: Radiopacification On (Coronal View)

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Figure 5: Polyp On Axial View

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Data Analysis

The data for the present study were entered in Microsoft Excel and analyzed using the SPSS version 2.1 statistical package. The Chi-square test and independent t-test were used to compare groups. P <0.05 was taken as the significant level. For descriptive statistics, mean, standard deviation, percentage, and frequency were calculated. The Chi-square test was used for the inferential statistics.

Sample size estimation

Based on the above formulae, at 95 percent confidence interval and 80 percent power of the study, the sample size was calculated to be 200 patients, and 400 sinuses were examined on the right and left side.

The patients were informed about their hidden asymptomatic pathological findings and were referred to a medical specialist for further consultation.

   Results Top

Our study included data of 200 subjects, i.e. 400 maxillary sinuses. After the statistical analyses, the data obtained was tabulated and were described in tables and graphs.

Out of 200 subjects included in our study, the overall prevalence of the mucosal thickenings was found to be 35%. The difference between mucosal thickening of the right and left sides of the maxillary sinus was statistically nonsignificant. [Table 1]
Table 1: Mucosal thickness intergroup comparison of mucosal thickness between the groups

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The incidental pathologies recorded in patients were found to be mucosal retention cyst (30%), polyps (5%), mucocele (0.5%), partial radio-opacification (3.5%), and complete radio-opacification (3.5%) on the left side. [Table 2] On the right side, incidental pathologies recorded in patients were found to be mucosal retention cyst (30.5%), polyps (3.5%), mucocele (0.5%), partial radio-opacification (5%), and complete radio-opacification (4%) [Table 3] Intergroup comparison yielded non significant differences [Table 4].
Table 2: Prevalence of incidental pathologies in left side sinus

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Table 3: Prevalnece of incidental pathologies in right side sinus

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Table 4: Intergroup comparison of pathologies between the groups

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   Discussion Top

This study was conducted among 200 patients for 1 year, 9 months. In this analysis, the average mean mucosal thickenings were 2.96 ± 2.91, 4.27 ± 0.34, and 5.26 ± 5.49 in the axial plane, the coronal plane, and the sagittal plane in the right sinus, respectively, with the sagittal plane indicating the higher mean value, i.e. 5.26 ± 5.49. In the left sinus, mucosal thickening was 3.04 ± 3.55 in the axial plane, 4.47 ± 5.10 in the coronal plane, and 5.45 ± 6.08 in the sagittal plane. It also showed a higher mean value (5.45 ± 6.08) in the sagittal plane. Hence, the intergroup comparison of mucosal thickening between the right and left sinus was found to be statistically not significant.

In the present study, the most prevalent finding was mucosal thickening, which showed an overall prevalence of 35% pathology and 65% non pathology.

A study conducted by Raghav M et al.[10] (2014) evaluated 201 patients (402 maxillary sinuses consecutive CBCT) for various incidental maxillary sinus pathology and found mucosal thickening to be 35.1%. Another study conducted by Mudgade D et al.[1] (2018) who evaluated 150 patients on CBCT between the age of 18 and 70 years reporting for routine dental complaints were analyzed for detecting pathology in the maxillary sinuses, and an overall prevalence of mucosal thickening was found to be 29.3%.

Rege et al.[4] (2012) evaluated 1113 CBCT scans for identification of abnormalities of the maxillary sinus and periapical lesions and proximity to the lower sinus wall was recorded, and the overall prevalence of mucosal thickening was found to be 66%.

Gracco et al.[11] (2012) conducted a study of 513 (1,026) maxillary sinuses on CBCT scans obtained for orthodontic diagnosis and treatment planning in a north Italian population, and found the prevalence of mucosal thickening to be 40.1%.

The difference in the findings can be due to indication and sample present in the study, the different age and patients groups present, the applied classification system in different studies.

Uniform height adjacent to the affected teeth is seen in the mucosal thickening due to chronic periodontitis. Localized mucosal thickening may occur when apical periodontitis affects a maxillary posterior tooth, or if periapical radiolucency is present, the mucosal thickening follows the radiolucency contour.[12] Although mucosal thickening is the most common radiographic finding observed regarding sinus pathology, the knowledge regarding its clinical significance on the outcomes of dental implants and grafting in the maxillary sinuses is still limited.[13] If the maxillary sinus mucosa showed thickening in the sinus floor, pathology in the maxillary sinus is suspected, which is possibly followed by a failure of osseointegration or acute maxillary sinusitis.[14] In cases with over 3 mm bone height and less than 4 mm of maxillary sinus mucosa, sinus augmentation surgery and simultaneous implant placement were performed. In cases of less than 3 mm residual bone height and over 4 mm of maxillary sinus mucosa, the staged surgical procedures were applied, and implants were placed after requirements were fulfilled. The follow-up examination was conducted 6–12 months after sinus augmentation. The failure criteria were postoperative infection, blocked nose, and implant loss before loading.[14]

Owing to ductal obstruction, the mucous retention cyst of the maxillary sinus (MRCMS) is a benign and self-limiting injury arising from mucus leakage within the sinus mucosa.[15] Many maxillary sinus retention cysts have spontaneous regression or remain stable in the long term without size changes.[16] Maxillary sinus retention cysts are normal incidental imaging findings and rarely have any clinical significance. It is assumed that retention cysts that resolve on follow-up imaging spontaneously rupture.[17]

In this study, mucosal retention cyst was found to be 30.5%, the polyp was reported to be 3.5% followed by 5% of partial radio-opacification, 4% of complete radio-opacification, and 0.5% of mucocele in the right sinus. In the left sinus, mucosal retention cyst was reported to be 30%, the polyp was 5%, partial radio opacification was 3.5%, complete radio-opacification was 3.5%, and mucocele to be 0.5%. Our findings indicate the most prevalent finding was mucosal retention cyst i.e. 30.5% in the right sinus and 30% in the left sinus, and mucocele was reported to be lesser i.e. 0.5% in both the right and left sinus. While comparing incidental pathologies in the left and right sinus, no association was found and was statistically not significant.

A study was conducted by Pazera et al.[18] (2010) examined orthodontic patients and determined the frequency using CBCT among 65 patients and found 46.8% incidental maxillary sinus pathologies.

Another study conducted by Malik et al.[6] (2018) among 231 patients analyzing the prevalence of pathological changes in the maxillary sinus of asymptomatic cases using CBCT showed a 37.2% incidence of maxillary sinus pathologies.

Ritter et al.[19] (2011) showed a 56.3% prevalence of incidental maxillary sinus pathologies using 1029 CBCT scans as a diagnostic tool to assist the prevalence of pathology findings in the maxillary sinus.

A similar study conducted by Raghav M et al.[10] (2015) which evaluated 201 patients for various incidental maxillary sinus pathologies by using CBCT images, the prevalence for total incidental findings was 59.7%, which was higher than our study.

Where the retention cyst fills the maxillary sinus, the radiographic interpretation becomes difficult, and complete blurring can be interpreted as maxillary sinusitis.[15]

The presence of any pathology in the maxillary sinus while performing sinus augmentation with the lateral technique may affect the success of sinus augmentation and, thus, the dental implants placed. Therefore, the preoperative examination of the maxillary sinus is essential for the success of the dental implant procedure during each stage.[20] There is one difference between acute sinusitis and chronic. Water or fluid amounts in acute sinusitis isolation occur within the maxillary sinus, but in chronic sinusitis, the thickening of the bone sinus wall is present.[1]

Limitations of the study

The study had several limitations, including the fact that it was done retrospectively with a small number of observers and imaging modalities. The type of the fluid (i.e., pus or blood) in radiopacification pictures was not differentiated since they seemed radiologically indistinguishable. Patients with radiopacity in the maxillary sinus due to maxillofacial trauma were eliminated, resulting in a smaller sample size. Despite its limitations, the research can aid in the early diagnosis and assessment of maxillary sinus disease in asymptomatic individuals.

Future Prospects

Identification of patient with an increased risk for developing odontogenic sinusitis should be considered a goal to achieve in the near future through this study. A correct diagnosis of odontogenic processes identifying dental cause is essential for successful treatment.

   Conclusion Top

There are lot of variations and pathology usually unnoticeable, and may become chronic if not diagnosed in the initial stage, and it may also hinder with the treatment and prognosis on dental treatment that require bone grafting, implant placement and sometime extraction and other pathologies. To image the accurate sinus anatomy and hidden pathologies, the use of CBCT was more favourable in the examination of the maxillary sinus anatomy as well as in the examination of the maxillary sinus pathologies. In our study, the mucosal thickening has a very high rate of incidental maxillary sinus pathologies in asymptomatic patients. Therefore, a detailed three dimensional radiograph using CBCT is indicated in most patients for proper treatment planning.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Mudgade DK, Motghare PC, Kunjir GU, Darwade AD, Raut AS. Prevalence of anatomical variations in maxillary sinus using cone beam computed tomography. J Indian Acad Oral Med Radiol 2018;30:18-23.  Back to cited text no. 1
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Ilze D, Ligija K, Peteris A, Gints K, Andris B. Radiographic assessment of findings in the maxillary sinus using cone-beam computed tomography. Stomatologija 2013;15:119-22.  Back to cited text no. 3
Rege IC, Sousa TO, Leles CR, Mendonça EF. Occurrence of maxillary sinus abnormalities detected by cone beam CT in asymptomatic patients. BMC Oral Health 2012;12:30.  Back to cited text no. 4
Deepjyoti M, Patel JS, Shankar TA, Sarada M, Vamsi KG, Prasanna G, et al. Prevalence of pathologic findings in MS in asymptomatic patients using cone beam computed tomography. J Clin Exp Pathol 2018;8:353.  Back to cited text no. 5
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  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]

  [Table 1], [Table 2], [Table 3], [Table 4]


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