Mental nerve paresthesia associated with endodontic pastewithin the mandibular canal: report of a caseRafael Poveda, MD,a José Vicente Bagán, MD, PhD,b José Maria Diaz Fernández, MD,c andJosé Maria Sanchis, MD, PhD,a Valencia, SpainGENERAL UNIVERSITY HOSPITAL

The present study describes a case of endodontic paste (Endomethasone) penetration within and along themandibular canal from the periapical zone of a lower first premolar following endodontic treatment of the latter. Theclinical manifestations comprised anesthesia of the right side of the lower lip and paresthesia of the gums in the fourthquadrant, 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 thebasic principles of endodontic treatment.1 Ideally, thefilling material should be limited to the root canalwithout extending to periapical tissues or other neigh-boring structures.

Totally biocompatible materials are not available.Consequently, their spread beyond the apical foramencan give rise to clinical manifestations in relation to thetoxicity of the product, though minor material extru-sions are generally well tolerated by the periradiculartissues.2 When the filling materials are either close to orin intimate contact with nerve structures, the toxiceffects 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 isa rapid and convenient technique, though it is difficultto confine the paste to the limits of the root canal. Forthis reason, most endodontists prefer a solid core and asealing cement. Pastes containing paraformaldehyde oreugenol can cause irreversible neurological damage andother adverse reactions. At present, these pastes are notrecommended for endodontic treatment.4

The present study describes a case in which end-odontic paste containing paraformaldehyde spread tothe mandibular canal, causing paresthesia and anesthe-

aAssistant in Stomatology, Department of Stomatology, General Uni-versity Hospital.bProfessor and Chairman, Department of Stomatology, General Uni-versity Hospital.cAssistant 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

sia in the area of innervation of the inferior alveolarnerve.

CLINICAL CASEA 40-year-old Gypsy woman appeared at the Service

of Stomatology (Valencia University General Hospital,Valencia, Spain) in July 2005. She neither smoked norconsumed 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 occurredimmediately 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 vestibulargingiva and in teeth 25-28.

No swelling, redness, or other signs of infection wereobserved at intraoral exploration. Extraoral examina-tion likewise failed to identify swelling, alterations inskin color, or adenopathies. The anesthetized zone wasdelimited by tactile exploration (Fig. 1).

Panoramic radiography (Fig. 2) revealed the presenceof radiopaque material (endodontic filler paste, specifi-cally Endomethasone; Specialités Septodont, Saint-Maur,France) in the periapical area of tooth 28, and spreadingalong the mandibular canal to beyond the distal root tip ofthe 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 firstpremolar (Figs. 3 and 4). In the anterior zone, the fillingmaterial was seen to emerge from the mental foramen(Fig. 5). We contacted the dentist, who explained that theroot canal treatment of the tooth had been carried outusing the step-back technique, followed by filling withEndomethasone (a paste of zinc oxide, paraformaldehyde,eugenol, corticosteroids [dexamethasone and hydrocorti-sone acetate], thymol iodide, lead oxide, and bismuthsubnitrite). The product had been introduced within the

canal by using a Lentulo spiral.

on the skin.

the periapical zone of tooth 28 and the inferior alveolar canal.

tal spread of the endodontic paste within the mental canal.

OOOOEVolume 102, Number 5 Poveda et al. e47

After discussing treatment options with the patient, itwas decided to monitor the progress with periodicfollow-up visits. Seven months later, she appeared withconsiderably less anesthesia in the region of the lowerright lip compared with the initial situation (Fig. 6). Thesensation of paresthesia in the gingiva and teeth of thelower right quadrant remained.

DISCUSSIONEndodontic treatment is common.5,6 The Table lists

the studies located by a Medline database search cor-

Fig 4. Computerized tomography. The sagittal view showscontinuity of the endodontic paste in the mandibular canaland the periapical area of tooth 28.

Fig 5. Computerized tomography. The axial view showsemergence of the endodontic paste through the mental fora-men.

Fig 1. The initial area of mental nerve anesthesia is outlined

Fig 2. Panoramic radiography showing endodontic paste in

Fig 3. Computerized tomography. Sagittal view showing dis-

responding to the period 1996-2005, in relation to the

OOOOEe48 Poveda et al. November 2006

subject of the present study, that is, sensory alterationsassociated with the presence of a foreign body in themandibular canal. Only 26 cases reported in 11 studieswere identified. Of these studies, only 3 explicitly iden-tified paraformaldehyde as the causal factor.7-10 Al-though it is very likely that paraformaldehyde also wasrelevant in the rest of the cases, the authors failed tomention the type of paste or cement used in the treat-ment.9-12 In an exhaustive study by Morse,13 a total of13 literature citations were documented between theyears 1963 and 1993, related to cases of mental nerveparesthesia due to the presence of paraformaldehyde inthe mandibular canal following endodontic treatment.Complications of endodontic treatment related to thepresence of foreign bodies, particularly paraformalde-

Fig 6. The area of mental nerve anesthesia after 7 months isoutlined on the skin.

Table. Neurological complaints associated with foreigFirst author/year Clinical manifestations

Kothary, 19967 Bilateral paresthesiaFanibunda, 199815 ParesthesiaGrotz, 19989 Neurological complaints (hypoesthe

dysesthesia)Yaltirik, 200210 Paresthesia and swellingBlanas, 200416 Pain and numbnessGallas-Torreiras, 200317 ParesthesiaYatsuhashi, 20038 ParesthesiaAlhgren, 200320 Hard, red, and painful swellingKnowles, 200319 ParesthesiaScolozzi, 200411 Pain with hypo-, an-, dys- and pare

Vasilakis, 200412 ParesthesiaPresent case, 2005 Paresthesia and anesthesia of the m

nerve

*Endodontic sealing material containing zinc oxide, hydrogenated res

eugenol.

hyde, in the mandibular canal are rare. Endodonticpastes are understood to represent those materials usedonly to fill the root canal, while cements are used as aninterface between solid filling material (silver tip orgutta-percha) and the walls of the root canal.

In regards to filler pastes and cements, Alantar etal.14 described 4 routes of spread from the periapicalzone: toward the mandibular canal, systemic diffusionthrough a periapical vein, drainage through lymphaticvessels, and progression toward soft tissues betweenbone and mucosal membrane. The case reported in ourstudy corresponds with the first of these routes.

Sealing cement and paste that spreads to the man-dibular canal is usually associated with alterations inconduction of the inferior alveolar nerve, with the de-velopment of anesthesia, hypoesthesia, paresthesia ordysesthesia resulting from the cytotoxicity of the com-ponents of the product employed.8,11

Materials traditionally considered to be inert (e.g.,gutta-percha) have also been reported as causal factorsof sensory alterations in the mental region after end-odontic treatment of premolars and molars. Most suchcases correspond to overfilling of thermoplastic gutta-percha within the mandibular canal (the Table docu-ments 4 cases), as a result of which the alteration isprobably of a thermal or mechanical nature (nervecompression).15-17 Calcium hydroxide, which is bio-compatible with bone, has also been implicated inirreversible nerve damage in experimental models18

and in patients.8 In this patient, the observed neurotox-icity was probably of a chemical origin. Brodin et al.3

examined the neurotoxic effect of filling materials andconcluded that products containing paraformaldehyde,which is added to endodontic pastes and cements for

y presence in the mandibular canal (1996-2005)No. of cases Material in mandibular canal

1 Paraformaldehyde (Endomethasone)1 Gutta-percha

11 Not specified

1 Paraformaldehyde (Endomethasone)2 Gutta-percha1 Gutta-percha2 Calcium hydroxide/paraformaldehyde1 Calcium hydroxide1 Grossman-type sealant*4 Endodontic paste (without

specification)1 Not specified1 Paraformaldehyde (Endomethasone)

uth subcarbonate, barium sulfate, anhydrous sodium tetraborate, and

n bod

sia and

sthesia

ental

in, bism

OOOOEVolume 102, Number 5 Poveda et al. e49

bactericidal purposes, may induce tissue alterations andpermanent nerve damage.

In addition, zinc eugenolate, which is a commoningredient in endodontic pastes and cements, hydro-lyzes to form zinc hydroxide and free eugenol. Thetoxicity of free eugenol is related to the inhibition ofcellular respiration and cytoplasmic membrane lysis,causing cell necrosis. Upon coming into contact withnerve tissue, eugenol is able to cause axon destructionand protein coagulation.10,13,19

It has been suggested that the use of a Lentulo spiralexerts less intracanal pressure than the use of a syringewhen applying filling pastes.20 In our case, despite theuse of the Lentulo spiral, the paste still migrated to themandibular canal and caused significant tissue damage.The symptoms appeared immediately after endodontictreatment in our patient, though in some cases a latencyperiod of up to 18 months is reported.9 After 7 monthsobservation, the paresthesia in the lower right gingivalarea and in teeth 25-28 persisted. The lip anesthesia hadimproved considerably.

The literature clearly demonstrates the good resultsobtained with sagittal mandibulotomy to secure directvisualization of the canal and facilitate elimination ofthe foreign material.11,15,21 No complications of thesurgical treatment are described, though with this tech-nique it has been reported that transient nerve alter-ations are seen in up to 80% of cases, with an incidenceof permanent nerve damage of 11%.22

REFERENCES1. Topalian M. Efecto citotóxico de los cementos selladores utiliza-

dos en endodoncia sobre el tejido periapical. Mayo: 2002. Avail-able from: http://www.carlosboveda.com

2. Pertot W, Camps J, Remusat M, Proust J. In vivo comparison ofthe biocompatibility of two root canal sealers implanted into themandibular bone of rabbits. Oral Surg Oral Med Oral Pathol1992;73:613-20.

3. Brodin P, Røed A, Aars H, Ørstavik D. Neurotoxic effects of rootfilling materials on rat phrenic nerve in vitro. J Dent Res1982;6:1020-3.

4. Consensus report of the European Society of Endodontology onquality guidelines for endodontic treatment. Int Dent J1994;27:115-24.

5. Boykin M, Gilbert G, Tilashalski K, Shelton B. Incidence ofendodontic treatment: a 48-month prospective study. J Endod2003;29:806-9.

6. Imfeld TN. Prevalence and quality of endodontic treatment in anelderly urban population of Switzerland. J Endod 1991;17:604-7.

7. Kothary P, Hanson N, Cannell H. Bilateral mandibular nerve dam-

age following root canal therapy. Br Dent J 1996;180:189-90.

8. Yatsuhashi T, Nakagawa K, Matsumoto M, Igarashi T, IchinoheT, Kaneko Y. Inferior alveolar nerve paresthesia relieved bymicroscopic endodontic treatment. Bull Tokyo Dent Coll2003;44:209-12.

9. Grotz K, Al-Nawas B, de Aguiar EG, Schulz A, Wagner W.Treatment of injuries to the inferior alveolar nerve after endodon-tic procedures. Clin Oral Investig 1998;2:73-6.

10. Yaltirik M, Ozbas H, Erisen R. Surgical management of over-filling of the root canal: a case report. Quintessence Int2002;33:670-2.

11. Scolozzi P, Lombardi T, Jaques B. Successful inferior alveolarnerve decompression for dysesthesia following endodontic treat-ment: report of four cases treated with mandibular sagittal os-teotomy. Oral Surg Oral Med Oral Pathol Oral Radiol Endod2004;97:625-31.

12. Vasilakis GJ, Vasilakis CM. Mandibular endodontic-related par-esthesia. Gen Dent 2004;52:334-8.

13. Morse DR. Endodontic-related inferior alveolar nerve and mental fo-ramen paresthesia. Compend Contin Educ Dent 1997;18:963-88.

14. Alantar A, Tarragano H, Lefèvre B. Extrusion of endodonticfilling material into the insertions of the mylohyoid muscle. OralSurg Oral Med Oral Pathol 1991;78:646-9.

15. Fanibunda K, Whitworth J, Steele J. The management of ther-momechanically compacted guttapercha extrusion in the inferiordental canal. Br Dent J 1998;184:330-2.

16. Blanas N, Kienle F, Sandor G. Inferior alveolar nerve injurycaused by thermoplastic guttapercha overextension. J Can DentAssoc 2004;70:384-7.

17. Gallas-Torreiras MM, Reboiras-López MD, García-García A,Gándara-Rey J. Parestesia del nervio dentario inferior provocadapor un tratamiento endodóncico. Med Oral 2003;8:299-303.

18. Boiesen J, Bodrin P. Neurotoxic effect of two root canal sealerswith calcium hydroxide on rat phrenic nerve in vitro. Endod DentTraumatol 1991;7:242-5.

19. Knowles K, Jergenson M, Howard J. Paresthesia associated withendodontic treatment of mandibular premolars. J Endod2003;29:768-70.

20. Ahlgren F, Johannessen AC, Hellem S. Displaced calcium hy-droxide paste causing inferior alveolar nerve parestesia: report ofa case. Oral Surg Oral Med Oral Pathol Oral Radiol Endod2003;96:734-7.

21. Evans AW. Removal of endodontic paste from the inferior al-veolar nerve by sagittal splitting of the mandible. Br Dent J1988;164:8-20.

22. Pogrel MA, Thamby S. The etiology of altered sensation in theinferior alveolar lingual and mental nerves as a result of dentaltreatment. J Calif Dent Assoc 1999;27:531-8.

Reprint requests:

Rafael Poveda, PhDGeneral University HospitalStomatologyAv/tres cruces S/N46020 ValenciaValencia, Spain

poveda_raf@gva.es