Odontogenic maxillary sinusitis (OMS) is an inflammatory disease caused by the spread of dental inflammation into the sinus. The long-term administration of antibiotic medicine and/or treatment of the causative tooth are the usual initial treatments. These initial treatments are not always effective, and the reason is not well understood. The purpose of this study was to identify factors of significance that may contribute to the results of the initial treatment of OMS. Thirty-nine patients were studied, divided into two groups according to the results of initial treatment: effective or non-effective. The effective group comprised 20 patients who were cured by initial treatment. The non-effective group comprised 19 patients who required an additional operation. The duration of symptoms, spread into the other sinuses, aperture width of the osteomeatal complex (OMC) on the side of the maxillary sinus, and anatomical variations in the sinuses were compared between the groups. The only significant difference found was in the aperture width of the OMC, which was significantly narrower in the non-effective group than in the effective group. The aperture width of the OMC may be a significant predictor of the effectiveness of initial treatment of OMS.
Odontogenic maxillary sinusitis (OMS) is an inflammatory disease caused by the spread of dental inflammation, directly or indirectly, into the sinus. OMS accounts for approximately 10–12% of maxillary sinusitis cases. OMS may be caused by the following: a chronic oral antral fistula, foreign bodies (dental fillings, tooth roots, parts of broken instruments) pushed through the root canal or antral fistula into the sinus, peri-apical granulomas or small inflammatory cysts of the molars and bicuspids, or large odontogenic cysts occupying the total or subtotal space of the maxillary sinus.
The treatment of OMS requires the management of sinusitis and the infectious source, which could be a tooth, implant, cyst, or tumour. Surgical treatment, such as a classical Caldwell–Luc operation, appears to be required for OMS caused by a large odontogenic cyst/tumour or a foreign body, such as an implant or extracted tooth. However, for OMS caused by a dental lesion, such as a peri-apical granuloma or small inflammatory cyst, initial treatment with the long-term administration of antibiotics and/or treatment of the causative tooth (tooth extraction or root canal treatment) has frequently been performed. The efficacy rate of these initial treatments for OMS has been reported to be 59.5%, indicating that these treatments are not always effective. Although the oral administration of antibiotics is effective against oral flora and sinus pathogens, administration for more than 3 months is not effective for OMS. The factors related to the success of these initial treatments have not been elucidated adequately.
The obstruction of the ostium of the maxillary sinus has been shown to be responsible for the majority of maxillary sinusitis cases. In cases where the initial treatment is not effective, surgery is required to open the obstruction of the ostium. There are two types of surgical approach: the Caldwell–Luc operation and functional endoscopic sinus surgery (FESS). In the Caldwell–Luc operation, the antral lining is removed completely, and the mucociliary lining is replaced with non-functional mucosa. Thus, the Caldwell–Luc operation appears to be detrimental to sinus physiology. In recent years, FESS has been used successfully as an alternative to the Caldwell–Luc approach for managing maxillary sinusitis. Its use has been extended to the treatment of OMS. FESS is less invasive compared to the Caldwell–Luc operation, allows the recovery of normal sinus function, and is characterized by spontaneous drainage from the natural ostium. However, these surgical treatments are traumatic and carry a risk of postoperative complications, such as bleeding, facial paraesthesia, and recurrent sinusitis. Thus, an invasive operation should be avoided when the symptoms improve without surgery.
In recent years, the osteomeatal complex (OMC), including the ostium of the maxillary sinus, has been shown to be an important anatomical index in the spectrum of sinusitis. The OMC consists of the maxillary ostium, ethmoidal infundibulum, uncinate process, ethmoid bulla, hiatus semilunaris, and middle nasal concha ( Fig. 1 ). The OMC is a functional entity of the anterior ethmoid complex that represents the final common pathway for drainage and ventilation of the frontal, maxillary, and anterior ethmoid cells. Anatomical variations that redirect nasal airflow or narrow the OMC have been implicated in the development of chronic rhinosinusitis. Opening a closed OMC could result in improvements in the symptoms of sinusitis. In OMS patients, opening a closed OMC and the appropriate initial treatment could result in an improvement of the OMS. Although the efficacy of rhinosinusitis treatment has been reported to be related to the anatomical structures of the OMC, there are few reports showing a correlation between the anatomical measurements of the OMC and the effectiveness of the initial treatment for OMS.