Maxillary Sinus: A Niche for Endodontic Mishaps?- A Systematic Review

Introduction

Endodontic therapy requires thorough anatomical knowledge and is performed respecting the neighbouring tissues to alleviate the pain and discomfort of the patient.¹ However, procedural mishaps cannot be always avoided thereby failing to meet the goal of endodontic therapy. During the course of treatment, the mechanical preparation followed by obturation is expected to confine to the contours of the root. Failure to accomplish this results in various iatrogenic errors that negatively affects the complete and successful healing.² Extrusion of irrigants, medicaments, sealers and obturating materials beyond the apex causes irritation to the tissues in the periapical region. The roots of maxillary molars and premolars lie in proximity to the floor of maxillary sinus, which often renders this anatomical location at high risk during dental therapeutic interventions.³ The root apices may often project onto the sinus floor or in some cases the bony sinus floor is replaced by a thin cortical bone or antral mucosa alone.⁴ Overextension of intracanal medicaments, endodontic sealers and obturating materials into the sinus presents with an array of clinical scenarios. Available case reports in literature often points to various complications that includes recalcitrant sinusitis, persistent pain, infections of fungal etiology such as fungi balls and aspergillosis.⁵

Patients mainly report to the physician or otolaryngologist or dentist with varying symptoms that includes pain in the ear, nose or upper teeth region, discharge, headaches or heaviness in the head. Post the assessment of patient, clinicians often render the diagnosis as “maxillary sinusitis”. Hence the treatment follows the regimen advised to eliminate this infection, thereby masking the key etiology which is required to be completely removed for the resolution of the ailment. Clinicians often fail to elicit a proper case history and employ adjunct diagnostic tools in these patients resulting in their prolonged distress and unwanted therapeutic interventions.

Examination of case reports showed the importance of tools such as radiographs and CT along with detailed history that helps to reach a confirmatory diagnosis. Currently no systematic review is available in the literature to outline the complications and associated prognosis of such cases. This systematic review aimed to highlight the complications, diagnosis, prognosis and outcome of the overzealous filling into the sinus.

Methods

The review was registered under prospero with the registration number CRD42020212264.

PEO question

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were employed for this review. The PEO questions employed were:

P (population): Patients who underwent endodontic therapy of the maxillary teeth.

E (exposure): Overfilling into the maxillary sinus.

O (outcome): Complications and prognosis of such patients.

Hence the review question asked was: “What are the expected complications and prognosis of root canal overfilling into the maxillary sinus?”

Search process and selection of studies

The databases were searched from January 2005 to August 2020 for potentially relevant studies in pubmed, google scholar, scopus, science direct and web of science. Manual searching of the grey literature was also done by going through university journals and publications, library dissertations and thesis works. The MeSH words used were: ((( maxillary sinus) or (paranasal sinus))) and ((( overfilling) or ( extruded filling) or ( gutta percha ) or ( endodontic sealer ))) and ((( complications) or ( outcomes ) or (prognosis))).

Inclusion/Exclusion Criteria

Inclusion criteria :

1. Patients with pain, otalgia, discharge, headache with history of endodontic intervention in the maxillary premolars and molars in the past or asymptomatic and discovered accidentally during routine dental examination.

2. Asymptomatic patients: accidental discovery during routine radiographic examination.

3. Extrusion of either intracanal medicament, sealer or obturating material into the sinus.

4. Radiographic (OPG/ CBCT) confirmation of extruded material.

5. Surgical removal of the specimens in the sinus (symptomatic patients).

6. Biopsy and histologic confirmation (symptomatic patients).

Exclusion criteria:

1. Studies published in other than English language.

2. No radiographic confirmation of diagnosis.

3. Extrusion of irrigants or separation of endodontic instruments.

Appraisal of the studies selected

Two authors separately assessed the quality of methodology based on the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for case reports. In the event of a disagreement, consensus was reached by discussion. The checklist consisted of eight appraisal questions with an overall appraisal whether to include or exclude the studies, or to seek further information from authors.

Results

Search findings and study characteristics

The search yielded 116 articles from various searchengines like pubmed/MEDLINE, scopus, google scholar, web-of-science using MeSH words. After screening and removing the duplicates, 89 articles remained. The titles and abstract text of 89 articles were assessed further that eliminated 40 articles due to inability to satisfy eligibility criteria. Forty nine articles that remained after this screening were further assessed based on the prior standardized list of criteria. Thirty three articles that did not meet the inclusion criteria were eliminated. The reviewers agreed upon 16 articles that were finally taken up for the qualitative analysis or systematic review.

Discussion

This qualitative analysis assessed the complications and prognosis of overfilling of endodontic material into the sinus. The various complications included persistent pain, recalcitrant maxillary sinusitis and infections of fungal etiology. Presenting symptoms included persistent pain in the region of upper jaw, otalgia, headaches, heaviness and nasal discharge that mimics maxillary sinusitis. Initial treatment regime mostly was aimed to curb the presenting signs or symptoms of the patients and not to eradicate the etiology. Failure to arrive at a definite diagnosis in such cases could be ascribed to the lack of eliciting a proper past dental history. Repeated history of sinusitis like symptoms should always raise the question of past dental treatment to dismiss any other possibilities.

The significance of radiological methods in the diagnosis has been highlighted in all the included studies. It was always (Orthopantomograpm) OPG, (Cone Beam Computed Tomography) CBCT or CT(Computed Tomography) along with IOPAR(Intraoral Periapical Radiography) that have aided in the diagnostic aspects. The readily available exposures in radiology are panoramic and periapical views. The floor of sinus along with its relation to the roots of maxillary teeth can be easily viewed in the panoramic view. Extruded sealers and obturating materials are viewed as radiodense objects in the radiograph and clearly helps in the diagnosis. CBCT and CT are more sensitive in evaluating maxillary sinus. It is viewed in different planes and axes leading to a 3D visualization. This helps to localize the foreign object if present in sinus space and its dimension can also be determined.³ Alteration in the surrounding wall thickness of the sinus could be differentiated through CT/CBCT suggestive of inflammation of sinus.1 With the radiographic evidence and past dental history, clinicians could clearly isolate the etiological factor and initiate proper treatment for the patients.

Recalcitrant maxillary sinusitis is often a sequelae of foreign objects in the maxillary sinus. This object could be either root fragment, root canal medicament, sealers or obturating material or the tooth itself. Extruded sealer and gutta percha in the included studies commonly presented with sinusitis. The patient reported with pain and swelling^1,6 associated with nasal discharge⁷ or otalgia and headaches.⁸ Gutta percha is extensively used as a root canal obturating material due to its inertness, biocompatibility and tissue tolerance.¹ However, retained gutta percha can result in persistent inflammation and sinusitis like symptoms.⁷ The onset of the symptoms usually occurs after a refractory period of six years.⁹ The disease subsides only after removal of the retained gutta percha from the sinus.^1,6,7 Case reports suggest that the gutta percha can migrate and block the maxillary ostium or even to the ethmoid sinus.^10,11

Sinusitis of odontogenic origin is often unilateral in nature. Odontogenic related sinus infections demonstrated more anaerobic flora in contrast to other infections of the sinus. This eventually could lead to fewer clinical symptoms and patients being diagnosed late causes a greater disease progression.¹²

Aspergillus mycetoma or fungi balls in the sinus secondary to over extrusion of gutta percha or sealer is a detrimental sequelae. This non-invasive form of aspergillosis occurs in healthy individuals. The predisposing factor in such cases is the significant zinc oxide content in the extruded material.¹³ Studies by Legent et al⁵ demonstrated that 85% of sinus aspergillosis is due to over extended sealers. The pathogenesis was attributed to the fact that aspergillus species can metabolize and avail these heavy metals for their survival, proliferation and maturation. These heavy metals may cause paralysis of cilia lining the walls of sinus and can cause alterations of the respiratory epithelium aiding in spore formation and proliferation of the fungal species. The diagnostic feature in mycotic infections is dense radiopacity of sinus as viewed in panoramic radiograph or CBCT. Medications cannot resolve this condition and requires surgical interventions such as surgical endoscopy or caldwell luc procedure. The microscopic examinations of such specimen revealed septate hyphae with 450 branching with adjacent inflammatory response. This hyphae could invade the adjacent vessels, occlude them and result in necrosis.¹³ Mycotic sinusitis remains asymptomatic for a long period of time making early detection impossible.

Fungal proliferation in the maxillary sinus following endodontic procedural accidents were extensively reviewed and studied upon. The heavy metals present in the endodontic filling materials gives a favourable environment for fungal growth and proliferation. Nicolai et al., in a case control study identified the heavy metals present in the biopsy specimens of maxillary fungal balls. High concentrations of zinc and copper were identified in these specimens. These heavy metals favoured the proliferation of the fungi species.

When foreign bodies get pushed into the sinus during endodontic procedures, the course of its complications varies. The size of the gutta percha or the amount of sealer extrusion also affects the prognosis.

According to Sjogren et al.,⁵ gutta percha can elicit two types of tissue responses. Larger size particles often gets encapsulated and surrounding tissues would be free of inflammation, while smaller particles could elicit an intense tissue reaction. The immune response of the patient varies resulting in different manifestations in different patients. If the sealer extrusion is minimal, it will result in a good prognosis with mild inflammation.¹⁴ Case report by Batur et al., showed an asymptomatic patient with an over extruded sealer (endomethasone) in the sinus. The patient in this scenario was kept under constant observation for a period of five years and remained asymptomatic. Ideally to prevent any consequences, surgical interventions is mandatory. But at times the sealer in the sinus could be reduced by the inherent resorptive process or eliminated by the pressure in antrum and lost via the nose that eventually leads to a good prognosis.⁴ In the included case reports, a common characteristic noted was the delay in reaching a definitive diagnosis. This can be attributed to the fact that patients were not well informed about the procedural mishaps and the potential complications that arise from it. Patient should be prepared to anticipate complications including maxillary sinusitis, aspergillosis and fungi balls. The symptoms pertaining to these conditions should be well explained to the patient. This will in turn help to keep a thorough lookout for complications and helps in immediate diagnosis and thereby its effective management.

Conflict of Interest

None.