RADIOGRAPHIC EXAMINATION OF MAXILLARY SINUS Radiographic examination of the. maxillary sinus may be . accomplished with a wide variety of exposures readily available in the dental office or radiology clinic.These exposures include periapical, occlusal; and panoramic views, which will, in most instances, provide adequate information to either confirm or rule out pathologic conditions of the sinus. If additional radiographic formation is required, Waters’ radiographs (Fig. 19-3) are usual-.ly diagnostic. Rarely, linear tomography (Fig. 19-4) and computed axial tomography (Fig. 19-5) of the structures in question may be necessary. , Interpretation of radiographs of the maxillary sinus is not difficult. The findings in the normal antrum are those to be expected of a rather large, air-filled cavity rounded by bone and dental structures. The body of the sinus should appear radiolucent and should be outlined in ll peripheral areas by a well-demarcated layer of cortical bone. It is helpful to compare one side to the other when examining the radiographs. There should be no evidence of thickened mucosa on the bony walls (usually indicative of chronic sinus disease) (see Fig. 19-3), air-fluid levels (caused by accumulation of mucus, pus, or blood) (Fig. 9-6), or foreign bodies lying free. Frequently, the apices of the roots of the posterior maxillary teeth and impacted third molars may be seen to project into the, sinus floor (Fig. 19- 7). In edentulous areas the sinus may be pneuma-tized into the alveolar process and extend almost to the alveolar crest. Complete opacification of the maxillarysinus may be caused by the mucosal hypertrophy and fluid accumulation of sinusitis, by filling with lood secondaryto trauma, or by neoplasia (Fig. 19-8). isruption of the cortical outline may be a result of trauma, tumor ormation, or surgical procedures that vio-late tha sinus walls.
FIG. 19-3 Waters’ radiograph showing mucosal thickening on right maxillary sinus’floor and lateral wall. Patient had oroantral fistula secondary to removal of first molar tooth and symptoms of chronic maxillary sinusitis.
FIG. 19-4 Tomogram of midface taken in frontal plane. Large, cystlike radiolucent lesion is seen to occupy bulk of right maxillary sinus (arrows). . .
FIG. 19·5 Computed axial tomogram of head in coronal plane. Both maxillary sinusesare almost totally opacified by mucosal lesions,asis right nasopharynx. Such lesions ar~ typica.1of allergic diseaseor chronic sinusitis RADIOGRAPHIC EXAMINATION OF AXILLARY SINUS FIG. 19·6 A, Waters’ radiograph demonstrates bilateral maxillary sinus air-fluid levels (arrows). 8, Lateral radiograph demonstrates alr-fluld levels in maxillary sinus (arrow), FIG.
Radiographic changes are to be expected with acute maxillary sinusitis and are secondary to filling of a normal, air-containing cavity with thickened mucosal sinus lining and accumulated mucus, pus, or both. Mucosal thlckentng secondary to odontogenic infections may obstruct the ostium of the sinus and allow accumulation of mucus, which will become infected and produce pus. The characteristic radiographic changes may include an air-fluid level in the sinus (see Fig. 19-6), thickened mucosa on any or all of the sinus walls (see Fig. 19-3), or complete opacification of the sinus cavity (see Fig. 19-8). The radiographic changes indicative of chronic maxillary sinusitis include mucosal thickening! sinus opacification, and nasal or antral polyps. Air-fluid levels in the sinuses are more characteristic of acute sinus disease but
rent in nature, obstructive nasal disease, or allergy. It is characterized by episodes of sinus disease that respond . initially to treatment, only tb return, or that remain symptomatic in spite of treatment. Aerobic, anaerobic, or mixed bacteria may cause infections of the maxillary sinuses. The normal healthy maxillary sinus has a small population of bacteria that is composed mainly of aerobic streptococd and anaer obicgram-negative rods of the genera Porphyromonas, Prevotella, and Fusobacterium. In maxillary sinusitis of nonodontogenic origin, the causative bacteria are primarily aerobic, with a few anaerobes. The important aerobes are Streptococcus pneumoniae, Haemophilus influenzae, .and. Staphylococcus aureus. Porphyromonas, Prevotella, Peptococcus,and Fusobacterium spp. are the common anaerobes.Maxillary sinus infections of odontogenic origin are more likely to be caused by anaerobic bacteria as is theusual odontogenic infection. Rarely does H. inftuenzae or S. aureus cause odontogenic sinusitis. The predominantor ganlsrr.s are aerobic streptococci and anaerobic Peptococcus, Peptostreptococcus, orphvromonas, Prevotetla, and Eubacterium spp. . . This information is important to the selection of ariantibiotic. The otolaryngologist usually chooses a drugthat is effective against H. influenzae and S. aureus, whichis not usually necessary for odontogenic sinusitis. Drug ssuch as penicillin, erythromycin; and clindamydn are effective for sinusitis of odontogenic ongtn ..However, because of the ide.variety of microorganisms that tan be participants iIl”Cnfectionsof the maxillary sinus, it is important to ohtam purulent material for culture and sensitivity (C&S) testerting wnenever possible.Sensitivity testing may su;’gest a change to otherantibiotic if resistant organisms are cultured from the sinus and if the infection is failing to respond to appropriate initial treatment Asmany as 25% of the organisms
cultured from acute sinus infections are beta-lactamase producers and many may be anaerobic, especially if theinfection is odontogenic in origin.