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 Table of Contents  
Year : 2016  |  Volume : 28  |  Issue : 2  |  Page : 179-182

Healing of recurrent sinus tract after retrograde endodontic treatment of an associated lateral canal

1 Department of Conservative Dentistry and Endodontics, Faculty of Dental Sciences, SGT University, Gurgaon, Haryana, India
2 Department of Conservative Dentistry and Endodontics, School of Dental Sciences, Sharda University, Noida, Uttar Pradesh, India

Date of Web Publication9-Dec-2016

Correspondence Address:
Ritu Sharma
Department of Conservative Dentistry and Endodontics, Faculty of Dental Sciences, SGT University, Budhera, Gurgaon - 122 305, Haryana
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0970-7212.195436

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A case report of the management of recurrent sinus tract associated with lateral canal is presented. In this report, a patient reported with a recurrent sinus tract after primary endodontic therapy. The sinus tract was traced with a gutta-percha point, which suggested the point of origin at the middle third of the root. An exploratory surgery revealed a lateral canal with extruded sealer. The canal was retroprepared and sealed with mineral trioxide aggregate. The sinus tract healed uneventfully. Postoperative healing of 18 months is presented. This case report demarcates the importance of lateral canals in endodontic pathosis.

Keywords: Intraoral sinus; lateral canal; retreatment.

How to cite this article:
Sharma R, Cheema RK. Healing of recurrent sinus tract after retrograde endodontic treatment of an associated lateral canal. Endodontology 2016;28:179-82

How to cite this URL:
Sharma R, Cheema RK. Healing of recurrent sinus tract after retrograde endodontic treatment of an associated lateral canal. Endodontology [serial online] 2016 [cited 2022 Dec 8];28:179-82. Available from: https://www.endodontologyonweb.org/text.asp?2016/28/2/179/195436

  Introduction Top

Thorough eradication of microbes remains the basic tenet for successful root canal therapy. Despite scrupulous treatment procedures, failures or unsuccessful outcomes are often encountered. These have been related to bacterial tenacity in areas unaffected by treatment procedures.[1] Anatomic irregularities such as accessory canals, isthumi, and lateral canals, hinder the ability to achieve the desired treatment results.[2]

Lateral canals are thought to arise either due to a gap in the Hertzwig's epithelial root sheath or due to a persistent blood vessel communicating from the dental pulp to dental sac, preventing dentin formation in this area.[3] Contents of these canals may be small blood vessels and sometimes nerves. Some teeth such as maxillary incisors may possess a higher incidence of lateral canals, as much as 60%.[4] Kramer has stated that in few cases, the diameter of lateral canals may be wider than that of apical constriction.[5]

Lateral canals are impossible to instrument and may only be partially cleaned by effective active irrigation with a suitable irrigant. Sealing such canals is also only moderately successful.

Owing to the limited disinfection and obturation of these canals, cases of persistent endodontic pathology attributable to them have been reported.[6],[7] We describe such a case here.

  Case Report Top

A 25-year-old woman reported to the dental schools' Department of Conservative Dentistry and Endodontics, with a chief complaint of acute pain and purulent discharge from the upper front teeth for 1 week. Her medical history was noncontributory, with no reported allergies. She was not on any medications, for any illness, except the usage of analgesics for pain. Further examination of the presenting complaint revealed two bilateral pustular raised points in the labial mucosa, at the mucogingival junction area, overlying the mid-root area of 11 and 21. The sites represented the previously active, now blocked, sinus tracts. Teeth 12 and 21 were grossly destroyed by caries. Teeth 11 had deep mesial and distal carious lesions [Figure 1]a. Teeth 11 was tender on vertical percussion. Periapical radiographs revealed diffuse periapical radiolucencies around the apices of 11 and 21 [Figure 1]b. Electric pulp vitality testing (Parkell pulp vitality tester Farmingdale, NY, USA) was done, and a negative response was obtained for all the three teeth. A diagnosis of pulp necrosis with chronic apical abscess was established for teeth 11. Teeth 12 and 21 were diagnosed to have pulp necrosis with asymptomatic apical periodontitis.
Figure 1: (a) Preoperative photograph, (b) Preoperative intraoral periapical x ray (c) Photograph of recurrent sinus tract over the incisor (d) Gutta-percha tracing of sinus tract, (e) File entering the lateral canal

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The clinical assessment of tooth mobility was done and recorded as Grade I for teeth 12 and 11. Treatment plan included composite restoration for 22; root canal treatment for 12, 11, and 21; crown lengthening for 12; cast post and core for 12; fiber post and core for 21; and finally, porcelain fused to metal crowns for 12, 11, and 21. Due to an increased cost and number of appointments for cast post and core, the patient decided to have fiber post and core for 12.

Disinfection of buccal soft tissue overlying teeth 11 and 21 was done with betadine and saline (50% each), and the pus was aspirated from the pustules, with a 23-gauge disposable needle and syringe (Dispovan, India). After rubber dam isolation and disinfection of operative field with betadine and saline (50% each), caries removal was performed. Under local anesthesia, root canal preparation was completed using liberal volumes of 5.25% of sodium hypochlorite (Prime Dental Products Pvt. Ltd., Thane, Mumbai, India) for irrigation. The canal was then filled with paste of pure calcium hydroxide powder mixed with saline and it was temporized. Teeth 12 and 21 were also treated in the similar manner.

The patient was recalled after a week. On the second visit, the pustules were clinically observed as healed, and the patient was relieved of the pain. The paste was removed from tooth 11 with files, and copious sodium hypochlorite irrigation was done. It was then obturated with cold lateral compaction technique, with gutta-percha and AH Plus sealer (Dentsply International Inc., York, PA, USA). Postendodontic restoration with composite was completed at the same sitting. Four days after the obturation, the patient returned with the complaint of pain, and the recurrence of a sinus tract, at the site of the previous pustular point on the upper right central incisor [Figure 1]c. Sinus tract tracing was done, and the gutta-percha on radiograph was seen vertically placed till the mid-root level of the central incisor [Figure 1]d. Suspecting a vertical root fracture, the patients' consent for an exploratory endodontic surgery was obtained.

Under local anesthesia, a triangular full-thickness mucoperiosteal flap was raised. Bit of granulation tissue and sealer located in a localized fashion on the middle third of the denuded labial root surface was curetted. Since the bone was fenestrated, there was no need for an osteotomy. It was sent for histopathological examination. One percent of methylene blue was applied to the exposed root to locate any crack or defect. Using loupes (Heine [Germany] HR × 2.5, 420 mm/162), an oval, tiny depression, around 1 mm in diameter, was noted in the middle third of the labial root surface. A lateral canal exit was observed in this depression, coinciding with the position of the previously observed sinus tract.

This lateral canal accepted a #10 K file [Figure 1]e. It was retroprepared with an ultrasonic tip. The prepared lateral canal was retrofilled with mineral trioxide aggregate [ProRoot MTA, Dentsply Tulsa, OK, USA] [Figure 2]a. The apical area of root along with the periapical tissues was left untouched.
Figure 2: (a) Mineral trioxide aggregate retrofill, (b) 1-year postoperative intraoral periapical photograph, (c) 1-year postoperative photograph, (d) 1-year and 7 months postoperative intraoral periapical photograph

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Flap was sutured, and postsurgical instructions were given to the patient. Hematoxylin and eosin staining of the histopathological specimen revealed hyperkeratinized stratified squamous epithelium surrounded by connective tissue stroma. Connective tissue stroma showed collagen fiber bundles with fibroblasts and lot of inflammatory cell infiltrates. It was suggestive of inflammatory hyperplasia.

One week after the surgery, adequate healing was observed, and the sutures were removed. The patient reported no pain or discomfort. This healing was again confirmed at the 1 month follow-up. Thereafter, crown lengthening [Figure 3] was done for tooth 12. It was followed by post and core and full-crown restorations for 12, 11, and 21. The patient was recalled for follow-up at 3 months, but the patient returned a year later. The healing was evident clinically and radiographically [Figure 2]b and [Figure 2]c. One year and 7 months later, the tooth remained completely asymptomatic and functional. The intraoral periapical photograph shows complete healing of the periapical lesion [Figure 2]d.
Figure 3: An externally beveled gingivectomy was performed by connecting the bleeding points with an incision angled at 45°, 1 week after crown lengthening and suture removal

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  Discussion Top

In the present case report, a painful sinus tract recurrence after endodontic treatment was associated with a lateral canal. The retropreparation and retrofilling of the lateral canal resulted in satisfactory healing as observed in the 18-month follow-up radiographs.

Weine in 1984 commented that painful sinus tracts may be attributable to lateral canals even in the absence of periapical radiolucency. He wrote an observation that teeth may fail laterally despite healing apically, due to the lateral canals. He maintained that these sinus tracts healed immediately following endodontic treatment, especially those with sealer extrusion. According to him, sealer extrusion forced the infected debris into the periradicular area, where there is a rich defense against such assaults.[7]

However, in our case, despite the sealer filling the lateral canal, healing was not observed. Most endodontic sealers are toxic before they set, but once set, they are well tolerated by periradicular tissues. In the case of extruded sealer, repair is observed once the initial inflammation subsides.[8]

A reason for the presenting sinus tract in our case could be that the contents of such a filled lateral canal may contain necrotic debris, sealer, and inflammatory cells.[9] Such contents are well capable of maintaining an inflammatory state. The histological examination of the graulation tissue, curetted from over the lateral canal in our case, exhibited inflammatory cell infiltrate.

We employed liberal amounts of 5.25% of sodium hypochlorite and 1 week of intracanal calcium hydroxide medication to disinfect the root canals. This regimen is advocated for the disinfection of necrotic canals.[10] Although the use of ultrasonic activation has been shownin vitro to better clean the lateral canals,[11] thein vivo scenario may be more challenging. The presence of tissue and various irrigation parameters such as time, concentration, volume, and refreshment affect the dynamics of irrigant-cleaning efficacy. A lateral canal may be more able to serve as an exit for endodontic infection, if the canal diameter is bigger and the canal contents are necrotic. A case reported by Ricucci et al. demonstrated lateral canal-based endodontic failure, despite adequate calcium hydroxide medication and passive ultrasonic irrigation.[6],[12]

It is well known that the conventional root canal treatment is not aimed at the disinfection of the lateral and accessory anatomy, and can leave the bacteria in these unaffected areas.[2] Despite the agitation of irrigant, the bacterial biofilms in the inner two-thirds of the dentinal tubules may remain untouched.[13],[14] In other case reports, Ricucci et al. histologically demonstrated bacterial biofilms, both on the outer surface of the root through the layers of cementum and the neighboring lateral canals.[15],[16]

Thus, these canals remain difficult-to-disinfect and may contribute to persistent endodontic pathosis.

  Conclusions Top

  1. Recurrent sinus tracts after endodontic therapy may be associated with lateral canals
  2. Adequate treatment of the associated lateral canal may result in complete healing
  3. Knowledge of this fact demands a dedicated research on the role of the third dimension in persistent disease, and on tools that can effectively disinfect it.


The authors deny any conflicts of interest related to this case report.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Fukushima H, Yamamoto K, Hirohata K, Sagawa H, Leung KP, Walker CB. Localization and identification of root canal bacteria in clinically asymptomatic periapical pathosis. J Endod 1990;16:534-8.  Back to cited text no. 1
Nair PN, Sjögren U, Krey G, Kahnberg KE, Sundqvist G. Intraradicular bacteria and fungi in root-filled, asymptomatic human teeth with therapy-resistant periapical lesions: A long-term light and electron microscopic follow-up study. J Endod 1990;16:580-8.  Back to cited text no. 2
Ida RD, Gutmann JL. Importance of anatomic variables in endodontic treatment outcomes: Case report. Endod Dent Traumatol 1995;11:199-203.  Back to cited text no. 3
Kasahara E, Yasuda E, Yamamoto A, Anzai M. Root canal system of the maxillary central incisor. J Endod 1990;16:158-61.  Back to cited text no. 4
Kramer IR. The vascular architecture of the human dental pulp. Arch Oral Biol 1960;2:177-89.  Back to cited text no. 5
Ricucci D, Loghin S, Siqueira JF Jr. Exuberant biofilm infection in a lateral canal as the cause of short-term endodontic treatment failure: Report of a case. J Endod 2013;39:712-8.  Back to cited text no. 6
Jang JH, Lee JM, Yi JK, Choi SB, Park SH. Surgical endodontic management of infected lateral canals of maxillary incisors. Restor Dent Endod 2015;40:79-84.  Back to cited text no. 7
Weine FS. The enigma of the lateral canal. Dent Clin North Am 1984;28:833-52.  Back to cited text no. 8
Metzger Z, Basrani B, Goodis HE. Instruments, materials, and devices. In: Hargreaves KM, Cohen S, Berman LH, editors. Pathways of the Pulp. 10th ed. St. Louis: CV Mosby; 2011. p. 269.  Back to cited text no. 9
Ricucci D, Siqueira JF Jr. Fate of the tissue in lateral canals and apical ramifications in response to pathologic conditions and treatment procedures. J Endod 2010;36:1-15.  Back to cited text no. 10
Metzger Z, Basrani B, Goodis HE. Instruments, materials, and devices. In: Hargreaves KM, Cohen S, Berman LH, editors. Pathways of the Pulp. 10th ed. St. Louis: CV Mosby; 2011. p. 254.  Back to cited text no. 11
Castelo-Baz P, Martín-Biedma B, Cantatore G, Ruíz-Piñón M, Bahillo J, Rivas-Mundiña B, et al. In vitro comparison of passive and continuous ultrasonic irrigation in simulated lateral canals of extracted teeth. J Endod 2012;38:688-91.  Back to cited text no. 12
Siqueira JF Jr., Araújo MC, Garcia PF, Fraga RC, Dantas CJ. Histological evaluation of the effectiveness of five instrumentation techniques for cleaning the apical third of root canals. J Endod 1997;23:499-502.  Back to cited text no. 13
Ricucci D, Siqueira JF Jr. Anatomic and microbiologic challenges to achieving success with endodontic treatment: A case report. J Endod 2008;34:1249-54.  Back to cited text no. 14
Ricucci D, Siqueira JF Jr., Lopes WS, Vieira AR, Rôças IN. Extraradicular infection as the cause of persistent symptoms: A case series. J Endod 2015;41:265-73.  Back to cited text no. 15
Ricucci D, Siqueira JF Jr. Apical actinomycosis as a continuum of intraradicular and extraradicular infection: Case report and critical review on its involvement with treatment failure. J Endod 2008;34:1124-9.  Back to cited text no. 16


  [Figure 1], [Figure 2], [Figure 3]


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