Non-surgical management of an extraoral cutaneous sinus tract of odontogenic origin

Abstract

Chronic apical periodontitis associated with dental pulp necrosis is the main cause of odontogenic extraoral cutaneous sinus openings. These tracts are often initially misdiagnosed unless the treating clinician considers a dental aetiology. This case report of a 19-year-old woman describes the diagnosis and treatment of an extraoral cutaneous sinus tract of odontogenic origin. Non-surgical conservative endodontic therapy was opted as the involved teeth were restorable. One month after the completion of obturation, there was closure of the sinus tract. One year follow-up showed complete resolution of the sinus tract with minimal scar formation.

Background

Odontogenic sinus tracts can open intraorally as well as extraorally.¹ Time and again the accurate diagnoses of such cutaneous sinus tracts have remained a challenge, as the initial appearance of these lesions are similar to other conditions such as skin infections, furuncles, ingrown hair or occluded sweat gland ducts, osteomyelitis, neoplasms, tuberculosis, actinomycosis, congenital midline sinus of the upper lip and carcinomas.^{2 3} The patients are mostly not aware of any dental issues as there would be no obvious symptoms.⁴ This has led to numerous incidences of multiple unsuccessful treatment routines, including surgical excisions, biopsies, systemic antibiotic regimens and also radiotherapy, all because the primary dental aetiology was never correctly identified or addressed.⁵

The following case report demonstrates a similar case of an odontogenic extraoral sinus tract which was misdiagnosed at first and following dental referral was successfully treated with routine non-surgical endodontic therapy. The lesion showed complete healing within a month after root canal treatment.

Case presentation

A 19-year-old woman was referred to the Department of Conservative Dentistry and Endodontics, Rajarajeswari Dental College and Hospital, Bangalore, India with the chief problem of a painful growth on the lower aspect of the chin since 1½ years. Patient reported with discomfort due to pain on touch and pus discharge from the nodular growth, which restricted her neck movements. Medical history was unremarkable. Dental history revealed that the patient had no memory of any dental trauma in relation to the anterior tooth region whatsoever. Almost a year back, following pus discharge from the lesion, the patient had consulted a physician who prescribed antibiotics (tab. cephalexin 500 mg) but with no effect. The patient was then referred to a dermatologist who carried out excision of the lesion with electrocautery after which the lesion recurred within 6 months.

On extraoral inspection, there was a submentally located, 2.5×3 cm erythematous, exophytic nodule with a crusted surface and a central stoma (figure 1A, B). Surrounding skin was tender to touch, and the lesion exuded pus on palpation. On intraoral examination, the mandibular anterior teeth were intact; however, there was a mild discolouration noticed in relation to teeth #31 and #32. On further examination, teeth #31 and #32 showed a negative response to pulp sensitivity tests and were tender on percussion. There was no mobility or any deep periodontal pockets present. Roentgenographical examination revealed a radiolucency associated with the periapices of teeth #31 and #32. Sinus tracing was done, in which a size 20 (ISO 0.02 taper) gutta percha point was introduced into the extraoral opening of the tract and a radiograph was taken with the gutta percha point in situ. The radiograph showed the GP cone pointing towards the lower left anteriors which was the source of infection (figure 2A, B). A final diagnosis of a chronic periapical abscess with an extraoral sinus opening was made in relation to teeth #31 and #32.

Figure 1.

(A, B) Clinical presentation before treatment.

Figure 2.

(A, B) Sinus tracing was done with size 20 gutta percha cone.

Differential diagnosis

The differential diagnoses include conditions, such as skin infections, pustules, furuncles, ingrown hair or occluded sweat gland duct, osteomyelitis, neoplasms, tuberculosis, actinomycosis and carcinomas.

Treatment

A conservative approach of non-surgical endodontic therapy was elected. Following isolation with a rubber dam, access cavity preparation was done on teeth #31 and #32. Buccal and lingual canals were detected in #32 while #31 had a single central canal. Initial working length was determined with an apex locator (Root ZX, J Morita) and was confirmed radiographically. Balanced force technique was opted for cleaning and shaping which was done using stainless steel K files (Mani, Japan) up to a size 35 (ISO 0.02 taper) for #31 and up to a size 30 (ISO 0.02 taper) in both canals of #32. Thorough irrigation was done with 2.5% sodium hypochlorite and 2% chlorhexidine solution following which the canals were dried. Calcium hydroxide was mixed with sterile saline solution to a creamy consistency and condensed into the root canals with dry paper points and left inside the root canal system for 14 days.

On the subsequent appointment after 2 weeks, the cutaneous nodule had condensed in size and looked cleaner and less erythematous and infected. The patient also reported reduced drainage from the lesion. After rubber dam isolation the root canals were copiously irrigated, dried and obturated by cold lateral condensation technique using AH plus sealer. Access cavity was sealed with Cavit. Permanent restoration was done 5 days after obturation using flowable composite (Tetric flow, Ivoclar).

Outcome and follow-up

At the 1 month follow-up, there was complete closure of the extraoral opening with significant healing. The nodular growth had almost disappeared and the patient was comfortable as there were no symptoms (figure 3).

Figure 3.

Presentation 1 month after treatment.

At 1 year follow-up there was complete healing of the sinus tract with scar formation. The teeth were asymptomatic and the patient was quite comfortable and satisfied with the treatment outcome (figure 4A, B).

Figure 4.

Clinical (A) and radiographical (B) presentation 1 year after treatment.

Discussion

The odontogenic cutaneous sinus tract on the facial and cervical skin mainly develops as a result of chronic periapical abscess associated with deep dental caries, chemical irritation or trauma.⁶ Literature indicates various other causes for the extraoral odontogenic sinus tracts, including retained tooth fragment, impacted tooth or odontogenic cyst,⁷ vertical root fracture,⁸ fractured crown by trauma⁹ and failing implant.¹⁰ The long-standing periapical infection causes inflammatory bone resorption. The infection erodes the alveolus and spreads peripherally assuming the path of least resistance within the fascial spaces and muscle attachments to eventually perforate the cortical bone and exit cutaneously. The formation of an extraoral sinus tract depends on the relative positions of the infected root apices and proximate muscle attachments and also the density of the investing bone.⁴ The most common site of occurrence of extraoral sinus tract opening has been reported to be the submental region.¹¹ Other reported sites of extraoral drainage of odontogenic origin are the cheek, angle of mandible, canine space, nasolabial fold, nasal mucosa, upper lip and inner canthus of the eye.^{4 5 11}

Approximately 50% of the patients go through unnecessary surgical excisions, radiotherapy, antibiotic therapy and multiple biopsies before the correct diagnosis is established.^{2 12} The initial presentation of the case along with the absence of any history of acute dental pain or discomfort makes the diagnosis of the odontogenic cutaneous sinus tracts challenging to the clinician. Since teeth with chronic periapical lesions may appear normal clinically with only a mild discolouration, radiographic analysis can be used to show a bone loss in the apex of the infected tooth, helping in the diagnosis.¹³ Not always does the sinus tract open in relation to the infected tooth, so in such situations, sinus tracing can be done by inserting a gutta percha point or a lacrimal probe into the sinus till resistance is felt and then exposing an intraoral periapical radiograph. Palpation can reveal a cord-like feel, seeming to be tethered to the underlying bone near to the offending tooth. Exudation can be observed by milking the sinus tract.⁷

Initially, sinus tracts were reported to be lined with epithelial tissue, providing the basis for the surgical treatment. However, later studies reported an absence of epithelial tissues and they also described that such tracts are generally lined with granulation tissue. Therefore, it has been established that endodontic treatment alone of the causative tooth can eliminate the need for surgical treatment. Thus non-surgical endodontic therapy using calcium hydroxide as intracanal medicament was done in this case. The antimicrobial properties of calcium hydroxide are achieved as a result of its dissociation into Ca²⁺ and OH⁻ ions along with its alkaline pH of 12.5.¹⁴ But it should be highlighted that several cases of odontogenic extraoral sinus tracts have been treated by surgical excision with the source of infection being a grossly decayed tooth or an infected extraction socket in association with osteomyelitic bone. In such cases, an endodontic treatment could not be considered as a mode of treatment.¹⁵

Systemic antibiotics are not indicated in the management cutaneous sinus tracts since it provides a pathway for drainage thus preventing swelling and pain. As a result, the draining sinus tract maintains a localised condition and prevents any systemic involvement. For this reason, no antibiotics were prescribed in this case. Failure to eliminate the dental focus of infection results in recurrence of the cutaneous sinus opening. Thus, the importance of considering a dental aetiology for a facial skin lesion cannot be stressed enough in timely diagnosis and treatment of such cases.¹⁶

Learning points.

• A possible dental origin should be considered while diagnosing cases of recurrent infected facial lesions.

• In the majority of such cases, a conservative non-surgical approach to treatment is sufficient if the source of infection is a restorable tooth.

• This case report describes non-surgical conservative endodontic management of a cutaneous sinus tract of dental origin in patients with a good host response.