Consequences of the overfilling in endodontic practice. Periapical reaction and potential complications

Background. Root canal filling is an important part of successful endodontic treatment. Hermetic apical sealing prevents apical leakage and the occurrence or recurrence of apical periodontitis. However, possible errors in chemo-mechanical preparation and obturation of root canals can lead to the risk of extrusion of materials beyond the apical foramen. The article gives a literature review on risk factors, complications during extrusion of sealer on the upper and lower jaw and ways to eliminate them, as well as clinical cases on the topic of the article. Aim – this literature review and keys reports aimed to evaluate the clinical and histological outcomes of the root canal filling material extrusion during endodontic treatment. Materials and Methods. Keywords of root canal filling, sealer extrusion, complications during endodontic treatment were searched for all obtainable publications in the databases of PubMed (https://pubmed.ncbi.nlm.nih.gov/), Clinical Key Elsevier (https://www.clinicalkey.com), Cochrane Library (https://www.cochranelibrary.com/), eBook Business Collection (https://www.ebsco.com/) and Google Scholar (https://scholar.google.com/). The success rate, short-term postoperative pain, overfilling and complications in upper and lower jaws were selected. Irrelevant reports were excluded. Clinical cases of the author presented the follow-ups of the root canal filling extrusions. Results. 75 relevant articles were identified. The full texts of articles were analyzed on the success rate, postoperative pain, overfilling and obturation. In the maxilla, the sealer can enter the sinus and lead to sinusitis, including aspergillosis, paresthesias, and neurologic complications. The excreted material is thought to not remain in one specific area of the sinus and exhibit foreign body properties. Stasis of secretion leads to anaerobic conditions that favor the growth of Aspergillus spores. Paresthesia can be a consequence of incorrect treatment due to pressure of obturation materials in the mandibular canal, neurotoxic effects, reversible or irreversible blocking of nerve impulse conduction, or disruption of the nerve fiber membrane potential. Another reason for failed endodontic treatment is a foreign body reaction. The filling material placed in the periapical zone causes a foreign body reaction in the connective tissue. Although the presence of filling material in the periradicular area does not lead to endodontic failure, it can significantly delay the healing process. The success rate of extrusion treatment is significantly higher in cases without periapical pathology compared to cases with apical periodontitis. 6 clinical cases of the author with the root canal filling material extrusions on the upper and lower jaw showed the clinical success in terms of absence of subjective symptoms and healing of the lesions in the long-term follow-ups. Conclusions. Based on numerous studies, it can be concluded that sealer extrusion is not a factor leading to poor healing, and resorption of the extruded material is not necessary for the repair of periapical lesion. It is unlikely that sealer extrusion can cause endodontic treatment failure, whereas infection is the main problem.