Odontogenic Sinusitis: Classification, Etiology, Clinical Presentation, Diagnosis, and Treatment

Odontogenic sinusistis (from the Greek odontos — tooth, and gennao — to generate) — is inflammation of the maxillary sinus caused by apical periodontitis of the maxillary teeth, most commonly of bacterial etiology. It differs from rhinogenic sinusitis in terms of its pathogenesis and treatment.

This disease lies at the intersection of otolaryngology and dentistry and is frequently overlooked by specialists. Every case of unilateral maxillary sinusitis should be considered potentially odontogenic until proven otherwise.

Classification of Odontogenic Sinusitis

There is no single classification system for odontogenic sinusitis. The following classification is proposed in this article.

By Etiopathogenesis

Depending on the cause and mechanism of development, the following forms of odontogenic sinusitis are distinguished:

Infectious odontogenic sinusitis:

• of pulpal origin;
• of periodontal origin;
• of endodontic-periodontal origin.

Iatrogenic odontogenic sinusitis:

• after tooth extraction;
• after implantation;
• after sinus lift;
• after endodontic treatment;
• after orthognathic surgery.

Associated with developmental abnormalities of the maxillofacial region:

• ectopic tooth;
• suppuration of a dentigerous cyst.

By the nature of the course

Based on the duration and nature of the inflammatory process, the following are distinguished:

• acute odontogenic sinusitis (up to 4 weeks);
• subacute odontogenic sinusitis (4–12 weeks);
• chronic odontogenic sinusitis (12 weeks or longer).

By localization

Depending on the extent of the inflammatory process, the following are distinguished:

• isolated maxillary sinusitis;
• diffuse sinusitis (with involvement of other paranasal sinuses).

By Morphological Changes

Based on the nature of pathologic changes in the mucosa, the following are distinguished:

• catarrhal sinusitis;
• purulent sinusitis;
• polypoid sinusitis;
• hyperplastic sinusitis.

By Communication with the Oral Cavity

Depending on the presence or absence of communication between the maxillary sinus and oral cavity, the following are distinguished:

• sinusitis with an oroantral communication (open form);
• sinusitis without an oroantral communication (closed form).

Epidemiology

According to data from publicly available sources, odontogenic sinusitis accounts for up to 45–75%of all cases of unilateral opacification of the maxillary sinus. Men comprise the majority of affected patients—approximately 65%; according to other studies, men and women are affected with equal frequency. The mean age of patients with this type of sinusitis is 45–50 years.

Among cases of odontogenic sinusitis, bacterial purulent sinusitis is the most common, accounting for 85%. Unilateral involvement is observed in 85% of cases. Periodontitis is reported as the cause of sinusitis in 60% of cases, dental implants in 20%, and tooth extraction in 19%. The first (39%) and second (38%) molars are significantly more frequently implicated in the development of this type of sinusitis. They are followed by the third molars (approximately 16%) and second premolars (8–21%).

Etiology

The main causes of odontogenic sinusitis include infections of the maxilla, complications from oral surgery (iatrogenic causes), and developmental anomalies of the maxillofacial region.

Infectious diseases leading to odontogenic sinusitis:

• apical periodontitis;
• periapical abscess, including an abscess with a fistulous tract into the maxillary sinus;
• suppuration of periapical cysts;
• periodontium diseases.

Complications of endodontic treatment:

• hematoma resulting from vascular injury in the periapical region;
• extrusion of debris;
• migration of fragments of endodontic instruments or filling material beyond the apical foramen;
• extrusion of irrigants (sodium hypochlorite) into the maxillary sinus;
• toxic effects of zinc oxide-eugenol–based sealers;
• perforation of the roots of teeth adjacent to the floor of the maxillary sinus or protruding into its lumen;
• sinus lift procedure;
• dental implantation;
• tooth extraction.

The development of odontogenic sinusitis associated with developmental abnormalities of the maxillofacial region is observed in cases of tooth ectopia or suppuration of a dentigerous cyst. Ectopia most commonly affects third molars (wisdom teeth) or canines, as well as supernumerary teeth.

An important factor in the development of the disease is the proximity of the infectious process to the maxillary sinus and thinning of the alveolar process. The risk of developing odontogenic sinusitis increases when the alveolar process is thinned to 3–4 mm in the presence of maxillary infection.

Among the pathogens causing this type of sinusitis, obligate and facultative anaerobes that are part of the oral microbiome predominate. The following pathogens have been described: Fusobacterium spp., Prevotella spp., Peptostreptococcus spp., Porphyromonas spp., Staphylococcus (S. aureus), Streptococcus (Str. intermedius, Str. constellatus, Str. anginosus, alfa-hemolytic Str.), Kl. pneumoniae, E. coli, Pr. mirabilis, Ps. aeruginosa.

In chronic odontogenic sinusitis, particularly when associated with iatrogenic causes, fungal flora has been identified in the sinuses. The most common fungi are those of the genera Aspergillus (80–90%), Actinomyces, Candida, Mucor.

Pathogenesis of Odontogenic Maxillary Sinusitis

The pathogenesis of odontogenic sinusitis differs somewhat depending on the etiological factor.

Infectious Mechanism

The presence of a periapical focus of bacterial infection in the maxilla, most commonly in the region of the first and second molars, causes destruction of the bone tissue of the alveolar process, which also forms the floor of the maxillary sinus. When the bone becomes critically thin (3–4 mm) or is perforated, anaerobic microflora enters the maxillary sinus. At the site of contact with pathogens, the sinus mucosa (Schneiderian membrane) becomes edematous, and mucociliary clearance is impaired. Mucous and subsequently purulent contents accumulate within the sinus. In the presence of rhinogenic anatomic factors, such as turbinate edema or a deviated nasal septum, combined with odontogenic edema, the maxillary sinus ostium may become obstructed. All of these factors lead to accumulation of fluid and progression of inflammation within the sinus. Subsequently, the process may become chronic, with mucosal proliferation and development of hyperplastic or polypoid sinusitis.

Mechanism in Iatrogenic Disease

The development of odontogenic sinusitis following complicated surgical procedures involving the maxilla is initially characterized by disruption of the integrity of the osteomucosal barrier between the maxilla and the maxillary sinus. During tooth extraction, implant placement, or sinus lift procedures, bone tissue is damaged, resulting in an overt or microscopic tear of the sinus mucosa (Schneiderian membrane). An oroantral communication or fistula develops.

Hematoma formation during endodontic treatment is caused by injury to maxillary blood vessels and extravasation of blood beneath the sinus mucosa (Schneiderian membrane) or directly into the maxillary sinus (resulting in hematosinus). This is associated with the fact that the roots of maxillary teeth, particularly premolars and molars, are often separated from the floor of the maxillary sinus by only a thin bony plate; in some cases, bone is completely absent and the root lies directly adjacent to the sinus mucosa. The blood clot provides a favorable nutrient medium for anaerobic microflora entering from infected root canals.

Subsequently, as in infectious sinusitis, microflora from the oral cavity enters the maxillary sinus, resulting in edema, accumulation of exudate, and subsequent obstruction of the ostium. In this form of the disease, fragments of tooth roots, bone fragments, fragments of surgical instruments, or filling material may also enter the sinus. In the presence of a foreign body within the sinus, the exudate rapidly becomes purulent. This also provides a favorable environment for fungal flora to develop, resulting in chronic sinusitis, polyp or mycetoma formation.

Mechanism in Developmental Abnormalities

The pathogenesis of odontogenic sinusitis associated with ectopic teeth and dentigerous cysts is caused by chronic pressure and gradual resorption of the bony wall separating these structures from the maxillary sinus.

Ectopic tooth is a developmental and positional abnormality in which the tooth bud develops and erupts outside the dental arch. In ectopia (retention), a tooth erupting toward the sinus creates a channel within the bone, traumatizes the ciliated epithelium, and is perceived by the body as a foreign object. This provokes localized inflammation and thickening of the mucosa.

If the ectopic tooth is located high within the sinus or the surrounding edematous tissues obstruct the natural sinus ostium, mucociliary clearance becomes impaired. Stagnant mucus creates an ideal anaerobic environment for bacterial proliferation. In some cases, a microcommunication with the oral cavity or the periodontal pocket of an adjacent tooth may persist around such a tooth, making the ectopic tooth a direct conduit for oral microflora to enter the sinus.

A dentigerous cyst develops from the follicular lining surrounding a tooth. As intracystic fluid accumulates, the cyst begins to expand, exerting pressure on the surrounding bone and causing bone resorption. A cyst growing in the maxilla gradually thins the inferior (alveolar) wall of the maxillary sinus and extends into its lumen. In the initial stages, the cyst contents are sterile. The cyst displaces the sinus mucosa, significantly reducing the volume of the aerated sinus; in some cases, the cyst completely occupies the sinus.

When local or systemic immunity is reduced, following trauma, hypothermia, or spread of infection from adjacent carious teeth, the fluid within the cyst becomes infected. When a dentigerous cyst becomes suppurative, the infectious-inflammatory process extends to the closely adherent mucosa of the maxillary sinus. The cyst wall frequently undergoes lysis, and a significant amount of pus ruptures directly into the sinus lumen.

In both cases, the critical event is infection of the cyst contents or the periapical tissues surrounding the ectopic tooth, resulting in rupture of purulent contents into the sinus and development of a persistent inflammation.

Clinical Manifestations

The following symptoms are characteristic of odontogenic sinusitis:

• unilateral purulent nasal discharge;
• nasal congestion;
• a sensation of an unpleasant odor in the nose or mouth;
• in the presence of an oroantral fistula — discharge of purulent material into the oral cavity;
• pressure-like facial pain on the affected side;
• headache;
• systemic symptoms — weakness, elevated temperature (most often to subfebrile levels), and sweating.

In acute odontogenic sinusitis, the clinical presentation is more pronounced and persists for up to 4 weeks. In subacute sinusitis, symptoms persist for up to 12 weeks. In chronic infection, symptoms are less pronounced; persistent, prolonged purulent rhinorrhea and nasal congestion on the affected side are more common. The clinical course is characterized by fluctuations, with periods of worsening symptoms and improvement in the patient’s condition, and persists for more than 12 weeks.

Symptoms involving the dentoalveolar system may or may not be present. These include pain with chewing and an aching pain in the maxillary teeth that worsens when the head is tilted.

Rarely, odontogenic sinusitis may present with extrasinus manifestations, such as orbital or intracranial complications (periorbital abscess, intracerebral abscess, meningoencephalitis, cavernous sinus thrombophlebitis), infection of the facial soft tissues, or osteomyelitis of the facial bones.

Diagnosis

Medical history and complaints are assessed first. A relationship may be identified between the onset of symptoms and dental pain or recent dental procedures involving the maxilla.

Odontogenic sinusitis is an interdisciplinary disease and requires evaluation and treatment by multiple specialists (an otorhinolaryngologist and a dentist).

ENT examination:

• purulent material and edema are visualized in the middle nasal meatus on the affected side;
• endoscopy reveals edema of the maxillary sinus ostium.

Dental examination:

• visual assessment of the maxillary teeth;
• probing;
• assessment of tooth mobility and percussion to identify the “causative” tooth;
• palpation of the soft tissues.

For endodontic evaluation, the most appropriate methods for confirming pulpal and periapical pathology are the cold test and electrical pulp testing. In equivocal cases, a drill test without local anesthesia may be performed.

When odontogenic sinusitis is suspected, cone-beam computed tomography (CBCT) is mandatory and demonstrates the relationship between the causative tooth and the maxillary sinus. If involvement of other sinuses (frontal, sphenoid, or ethmoid) is suspected, CT of the paranasal sinuses may be performed. The posterior ethmoid and sphenoid sinuses are rarely involved in odontogenic sinusitis. However, according to statistical data, radiologists rarely identify a relationship between sinusitis and an odontogenic source (in fewer than 25% of cases).

It is important to remember that every case of unilateral maxillary sinusitis should be considered potentially odontogenic until proven otherwise.

Diagnostic criteria for odontogenic sinusitis:

1. Presence of clinical symptoms of sinus inflammation (with or without oral symptoms).
2. Presence of diseased maxillary teeth on the same side as sinusitis, with periapical lesions or severe alveolar bone destruction (up to ⅔ of the root length or greater) on CBCT.
3. Presence of a foreign body within the maxillary sinus or an oroantral fistula on the same side as the sinusitis.
4. CT/CBCT imaging demonstrates a fluid level/opacification of the maxillary sinus/mucosal thickening of the sinus (greater than 2 mm), limited to an oral cavity lesion on the same side as the sinusitis, with evidence of:

• 4a. disruption of the maxillary sinus floor between them;
• 4b. a thin layer of bone of the maxillary sinus floor between them;
• 4c. a thick layer of bone of the maxillary sinus floor between them.

Levels of diagnostic evidence:

• definitive evidence — patients meeting criteria 1, 3 or 1, 2, 4a;
• potential evidence — patients meeting criteria 1, 2, 4b;
• questionable evidence — patients meeting criteria 1, 2, 4c.

Find more scientifically accurate content on our social media

Subscribe and don’t miss out the latest resources

Treatment of Odontogenic Sinusitis

Odontogenic sinusitis is a multidisciplinary disease requiring close collaboration between a maxillofacial surgeon, dentist, and otorhinolaryngologist. The complexity of treatment lies in the need to simultaneously eliminate the infectious focus in the oral cavity and control inflammation in the maxillary sinus.

Currently, there is no single universal protocol within the medical community, requiring individualized treatment planning based on the etiology of the process (presence of a foreign body, cyst, or apical periodontitis).

One of the main principles is combined treatment of the dental pathology and sinusitis.

Main stages of odontogenic sinusitis treatment:

1. medication Therapy;
2. treatment of the primary focus of infection;
3. closure of an oroantral fistula or communication, if present;
4. treatment and sanitation of the maxillary sinus.

Medication Therapy

Medical therapy for odontogenic sinusitis is aimed at suppressing bacterial infection, reducing mucosal edema, and restoring normal sinus drainage. It is rarely used as a standalone treatment and more commonly supplements surgical treatment or serves as a temporary measure to relieve symptoms.

The following groups of medications are recommended:

• systemic oral antibacterial agents — protected penicillins, II-III generation cephalosporins, fluoroquinolones, and metronidazole;
• nasal decongestants and glucocorticoids, and nasal irrigation therapy — these medications reduce edema in the region of the natural maxillary sinus ostium and facilitate drainage of sinus contents;
• anti-inflammatory medications (ibuprofen, nimesulide) — to relieve pain and reduce inflammatory responses;
• mucolytics (acetylcysteine, herbal preparations) — thin the pathological secretions within the sinus, facilitating their evacuation through the natural ostium.

Treatment of the Primary Focus of Infection

Management of the “causative” tooth in odontogenic sinusitis is based on assessment of its prognosis. When the surrounding tissues are in satisfactory condition, preservation of the tooth through endodontic treatment or apical surgery is preferred. However, when the prognosis is questionable and the infection is uncontrolled, extraction is indicated. It results in successful treatment in most cases but does not always guarantee complete resolution.

In cases of developmental abnormalities of the maxillofacial region, surgical removal of the focus is performed because conservative methods are ineffective. In cases of ectopic teeth, extraction may be performed through an intraoral approach or endoscopically through the nasal cavity if the tooth is significantly displaced into the sinus. For dentigerous cysts, particularly when suppuration is present, cystectomy — complete enucleation of the cyst wall — is performed.

Closure of an Oroantral Fistula or Communication

When a perforation of the Schneiderian membrane and a communication between the oral cavity and sinus are identified, simultaneous closure of the communication (together with treatment of the primary infectious focus) or delayed closure and fistula repair must be performed.

Management of patients with oroantral communications and fistulas:

• Spontaneous healing. Small oroantral communications (1–2 mm in diameter) without evidence of epithelialization are prone to spontaneous closure in most cases.
• A conservative, wait-and-see approach. For small communications demonstrating delayed closure but not causing inflammation of the maxillary sinus, observation with follow-up is indicated. Probing and irrigation of the defect are strictly contraindicated in these cases. With adherence to protective measures, closure occurs within 3–4 months.
• Indications for surgery:
  • oroantral defects 5 mm or greater in diameter that persist for more than three weeks;
  • concomitant sinus infection and persistence of the communication for more than three weeks, regardless of the diameter of the defect (including defects smaller than 5 mm);
• Risk factors for chronicity. Epithelialization of the fistulous tract, as well as osteitis of the margins of the defect associated with odontogenic abscesses, cysts, neoplasms, or foreign bodies, contribute to the development of a chronic oroantral fistula and prevent spontaneous healing.

Sanitation of the Maxillary Sinus

Sanitation of the maxillary sinus is an important stage of treatment aimed at complete evacuation of purulent exudate, necrotic tissue, and polypoid growths to control the inflammatory process.

Surgical intervention is performed using FESS (Functional Endoscopic Sinus Surgery) through the nasal cavity under endoscopic visualization. The natural ostium is enlarged (antrostomy), providing direct access to the inflammatory focus, and the sinus is cleared. This technique allows removal of purulent contents, foreign bodies (root fragments, filling material, instrument fragments, or implants), and polypoid mucosa without traumatic incisions in the oral cavity.