Cone Beam Computed Tomography in an Evaluation and Diagnosis of Anatomical Variations and Pathological Lesions in Maxillary Sinus Prior to Maxillary Sinus Lift Surgery

Thorough assessment of the maxillary sinus is very important. Recently 3-dimensional image with Cone Beam Computed Tomography (CBCT) is very dependable in Maxillary Sinus diagnosis. The aim of this study is to: shade light on the role of (CBCT) diagnosis of the maxillary sinus anatomical variation and pathological finding among smokers and nonsmokers prior to maxillary sinus lift techniques. Materials and Method: In this study 60 males with age ranged between 20-50 years old, referred for (CBCT) assessment of maxillary sinus in the Specialist Health Center of Al-Sadder city. The scanning were performed using Kodak 9500 (CBCT), the KV was 90, mA10 and scanning time 10 s. Voxel size 0.3mm with( DICOM ) software on a multiplaner reconstruction window in which the axial, coronal and sagittal plane could be visualized in 0.3 mm interval, 40 were smokers and 20 nonsmokers, both sides were evaluated to assess the presence of septa, maxillary sinus membrane (Schneiderian membrane)thickening, complete opacification and adenoid polyp. Result:The maxillary for nonsmoker patients (20) patients were clean and have no any pathological or anatomical changes, among smoker patients, it was found that 7 (17.5%) of them had a clean maxillary sinus, 25 (62.5%) patient from smokers, the mucosal thickening was clear and measured more than 4 mm, 20 (80%) of them bilateral maxillary sinus were involved and 5 (20%) of them have a unilateral thickening, 6 (15%) of the smoker patient have bilateral involved adenoid with max sinus, and 2(5%) of them have full opacification., no septa was found in this study. Conclusion:Cone Beam Computed Tomography(CBCT)was themost useful technique to diagnose maxillary sinusbefore maxillary sinus augmentation, an evaluation ofCone Beam Computed Tomography(CBCT)scans before implant surgery or sinus augmentation procedures has extreme clinical importance in evaluation of anatomic structures, such as thickening of the Schneiderian membrane and presence of pathological lesion such as adenoid polyp.


INTRODUCTION
Sound knowledge of maxillary sinus and its anatomical variationsis very importantfor surgeons,especially before surgical procedures, such as insertion of dental implants with or without maxillary sinus lifting (1)(2)(3) .Anatomic variations within the sinus, such as septa and mucosal thickening of the sinus floor increase the possibility of the sinus membrane perforation during pre-implant surgery in maxillary sinus (4) .
Very few knowledge about the thickening and the dimension of the maxillary sinusmembrane, there is no specific method for evaluationand classification of mucosal findings in it.Many findings determined that, the thickening of maxillary sinus mucosa less than 2 mm was consider asa normal variant (5,6) .
Radiographically, the normal maxillary sinus, because it is air filled so it is radiolucent structure, while its walls appear as radiopaque (7) .In the case of a diseased sinus, a radiologist may observe clouding (opacifying) or mucosal thickening (8) .
(1) Lectuere, Department of Oral Diagnosis, College of Dentistry, University of Baghdad.
Thorough assessment of the maxillary sinus is very important.Panoramic imaging technique is used widely in dentistry but it is still 2dimensional image that loss some important anatomical details recently, (CBCT) isconsidered as an acceptable alternative.Since the end of 90s(CBCT) has become a popular imaging technique in dentistry, even for visualization of the paranasal sinuses (9,10) .
(CBCT) can accurately capture, display and provide undistorted 3-dimensional view of maxillofacial anatomy and pathology.It is important to be acquainted with different anatomic and pathologic findings in maxillary sinus, (CBCT) scanning has become the standard in dentistry for evaluating the maxillary sinuses because of the ability to accurately scanning the sinus in multiple views with thin sectioning (11) .(CBCT) images allow localizing the anatomic structures and providing information about bone dimensions and morphology (12,13) .The relationship between smoking and thickening of sinus mucosa was directrelationship (17) .
The effect of smoking and non-allergic inhalants cause chronic inflammation of the nasal and sinus mucosa which may lead to adenoid polyp formation (18) .The present study was designed to: 1-Shed light on the importance of (CBCT) in pre implant evaluationfor patients who have alveolar bone loss in the maxillary sinus area.2-To compare the maxillary sinus appearance and pathological images between smokers and nonsmokers.

MATERIALS AND METHODS
In the present study 60 males with age ranged between 20-50 years old,(mean 35 years)referred to(CBCT) scanning for maxillary sinus in Specialist Health Center in AL-Sadder City.The scanning were performed using Kodak 9500 (CBCT), French origin, the Kv was 90, mA10 and time of scan 10 s.Voxel size 0.3mm with(DICOM) software on a multiplaner reconstruction window in which the axial, coronal and sagittal plane could be visualized from period between September 2014 to march 2015.
CBCTscan was done for all patients to assess the presence of any anatomical variation or pathological finding pre implant associated with maxillarysinusaugmentation.
Scanning of maxillary sinus was performed by using three orthogonal slices.The (CBCT) scans were analyzed by independent two readings by the specialist radiologist.The criteria of evaluation based on scanning of:(1) presence of septa, (2)mucosal thickening more than 2mm,(mucosa was measured from different point corresponding to the underlying bone in the area of 1 st ,2 nd premolars and 1 st ,2nd molars, the highest point was recorded),(3)full opacification of maxillary sinus and/or any other (4) pathological finding.Classification of mucosal thickening (14) .
All patients were asked about: Age, tobacco use, classified as with duration of more than 2 years, history of sinusitis and time of last extraction.All patients were informed about the aim and method of the study and they fill a special consent form after their agreement in participation.
Chi square statistical analysis was used to compare the result finding between smokers and nonsmokers.As shown in the table nonsmoker patient pathological or anatomical changes

DISCUSSION
In the present study after the evaluation of maxillary sinus it was found that the thickening of sinus membranehas the highest percentage among the other changes (62%), while the full opacification was found in only 2patients (5%) ,this com in conformity with Ilze et al., (15) who found that, there was thickening in 19 patient from 33 patient, 14 bilateral and 5 unilateral , slight difference of the percentage between twostudies may be due to sample size differences and also conform with Regaetal., (16) who stated that, the most prominent anatomical changes was thickening of maxillary sinus membrane followed by full opacification.
It is clear thatthere is a direct relationship between smoking and thickening of sinus mucosa which is agreement with Janner et al., (17) .
In this study, it was found that 6 patients involved with adenoid polyp and all of them were bilatera, since the smoker effect on the sinuses as its effect on lung epithelial, especially these adenoid were found only among smoker patientsand this disagree with Ilze et al., (15) who found no pathological findings among his sample.
While Gorgulu et al., (18) result is very near to the presentresults, they approved that, smoking is found to be the only risk factor for development of maxillary sinus and nasal polyp, and they concluded that the smoking restriction and avoiding exposure to cigarette smoking by patient with nasal polyps may be important in prevention of the recurrence of nasal and sinus polyp.
According to the result of thepresent study,one can considerCBCTasan accurate diagnostic tool to evaluate the anatomical changes pathological disease in maxillary sinus and significant effects of smoking on maxillary sinus.

Figure 2 :
Figure 2: Coronal view Showing Unilateral Thickening of Maxillary Sinus Membrane