Mental nerve paresthesia associated with endodontic paste within the mandibular canal: report of a case Rafael Poveda, MD, a José Vicente Bagán, MD, PhD, b José Maria Diaz Fernández, MD, c and José Maria Sanchis, MD, PhD, a Valencia, Spain GENERAL UNIVERSITY HOSPITAL The present study describes a case of endodontic paste (Endomethasone) penetration within and along the mandibular canal from the periapical zone of a lower first premolar following endodontic treatment of the latter. The clinical manifestations comprised anesthesia of the right side of the lower lip and paresthesia of the gums in the fourth quadrant, appearing immediately after endodontic treatment. The lip anesthesia was seen to decrease, with persistence of the gingival paresthesia, after 7 months. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2006;102:e46-e49) The elimination of infected pulp and dentin, and ade- quate root canal preparation and sealing constitute the basic principles of endodontic treatment. 1 Ideally, the filling material should be limited to the root canal without extending to periapical tissues or other neigh- boring structures. Totally biocompatible materials are not available. Consequently, their spread beyond the apical foramen can give rise to clinical manifestations in relation to the toxicity of the product, though minor material extru- sions are generally well tolerated by the periradicular tissues. 2 When the filling materials are either close to or in intimate contact with nerve structures, the toxic effects can manifest in the form of anesthesia, hypoes- thesia, paresthesia, or dysesthesia that may prove irre- versible. 3 The use of pastes as sole endodontic filler material is a rapid and convenient technique, though it is difficult to confine the paste to the limits of the root canal. For this reason, most endodontists prefer a solid core and a sealing cement. Pastes containing paraformaldehyde or eugenol can cause irreversible neurological damage and other adverse reactions. At present, these pastes are not recommended for endodontic treatment. 4 The present study describes a case in which end- odontic paste containing paraformaldehyde spread to the mandibular canal, causing paresthesia and anesthe- sia in the area of innervation of the inferior alveolar nerve. CLINICAL CASE A 40-year-old Gypsy woman appeared at the Service of Stomatology (Valencia University General Hospital, Valencia, Spain) in July 2005. She neither smoked nor consumed alcohol, and had no personal or family dis- ease antecedents of interest. The patient reported numb- ness on the right side of the lower lip that had occurred immediately after root canal treatment of tooth 28, which was carried out by her dentist 15 days earlier. She also reported a tingling sensation in the vestibular gingiva and in teeth 25-28. No swelling, redness, or other signs of infection were observed at intraoral exploration. Extraoral examina- tion likewise failed to identify swelling, alterations in skin color, or adenopathies. The anesthetized zone was delimited by tactile exploration (Fig. 1). Panoramic radiography (Fig. 2) revealed the presence of radiopaque material (endodontic filler paste, specifi- cally Endomethasone; Specialités Septodont, Saint-Maur, France) in the periapical area of tooth 28, and spreading along the mandibular canal to beyond the distal root tip of the lower right second molar. Computed tomography con- firmed the presence of radiopaque material in the periapi- cal area of tooth 28, with extension along the right man- dibular canal from the periapical zone of the lower first premolar (Figs. 3 and 4). In the anterior zone, the filling material was seen to emerge from the mental foramen (Fig. 5). We contacted the dentist, who explained that the root canal treatment of the tooth had been carried out using the step-back technique, followed by filling with Endomethasone (a paste of zinc oxide, paraformaldehyde, eugenol, corticosteroids [dexamethasone and hydrocorti- sone acetate], thymol iodide, lead oxide, and bismuth subnitrite). The product had been introduced within the canal by using a Lentulo spiral. a Assistant in Stomatology, Department of Stomatology, General Uni- versity Hospital. b Professor and Chairman, Department of Stomatology, General Uni- versity Hospital. c Assistant in Oral and Maxillofacial Surgery, Department of Stoma- tology, General University Hospital. Received for publication Mar 5, 2005; returned for revision Mar 18, 2005; accepted for publication Mar 20, 2006. 1079-2104/$ - see front matter © 2006 Mosby, Inc. All rights reserved. doi:10.1016/j.tripleo.2006.03.022 e46