Abstract

Background: This article reports on a case of extraosseous inflammatory lesion of endodontic origin (EILEO) that was recalcitrant to nonsurgical root canal treatment and was caused by a complex intraradicular and extraradicular bacterial infection.

Case description: The histopathological and histobacteriological aspects of the biopsy specimen were evaluated. The affected tooth was a mandibular premolar that exhibited an abraded crown with exposed dentin and enamel cracks, but no caries. The patient reported previous abscess episodes and presented with symptoms and a sinus tract. Nonsurgical root canal treatment was not effective in controlling infection, even after using ultrasonic agitation of irrigants and intracanal medication. Surgery was indicated and the biopsy specimen including the extraosseous extension was processed for histopathological and histobacteriological analyses. Bacterial infection in the form of biofilms and planktonic cells was observed not only in the main apical root canal, but also in ramifications and extending to the extraradicular environment. The intraosseous part of the lesion showed severe inflammation in the areas surrounding the root apex and the extraradicular biofilms. The extraosseous tissue showed an abundance of collagen fibers externally, and inflammatory tissue layering the sinus tract internally.

Conclusion: EILEO can be regarded as a different manifestation of apical periodontitis and its prevalence and clinical implications remain to be clarified.

Introduction

Apical periodontitis is an inflammatory disease caused by bacterial infection of the root canal system (Ørstavik 2020). The disease may have different clinical manifestations, but radiographically it is usually associated with a radiolucent area in the bone tissue apically or laterally to the root. This is caused by bone resorption that affects the cancellous and, in many cases, can evolve to perforate the cortical plate (Jalali et al. 2019).

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