DTME0410

M isdiagnosis of an extra-oral sinus tract usually leads to a destructive invasive treat- ment of the local skin lesions that is not curative and often mutilating (Fig. 1). Attempting to treat such lesions with a circular incision of the orifice of the cutaneous fistula and excision of its entire tract with all the ramifica- tions is not consistent with the present standard of care. Unfortunately, cuta- neous fistulae are sometimes treated as though they are independent der- matologic lesions with the pathogenic characteristics and treatment progno- sis typical for mucosal fistulae. How- ever, even skin biopsy may produce unnecessary scarring. Correct diagnosis is the key to treating this kind of lesion. A gentle digital finger pad pressure on the api- cal region of the area suspected can create a discharge of pus. A DentaS- can can provide reliable information that will help with the final diagnosis and the subsequent treatment plan. A correct diagnosis will lead to a simple, yet effective treatment—the removal of the infected pulp canal tissue from the root canal space—resulting in minimal cutaneous scarring. Cutaneous sinus tracts of dental origin have been well document- ed in the medical literature,dental literature,and dermatological litera- ture. However, these lesions continue to be a diagnostic dilemma. Patients suffering from cutaneous fistulae usu- ally seek treatment from a physician or a plastic surgeon instead of a den- tist and often undergo multiple surgi- cal excisions, multiple biopsies and antibiotic regimens with eventual re- currence of the cutaneous sinus tract because the primary dental cause is frequently misdiagnosed. The evaluation of a cutaneous sinus tract must begin with a thor- ough patient history and awareness that any cutaneous lesion of the face and neck could be of dental origin. The patient’s history may include complaints of dental problems. However, patients may not have any history of an acute or painful onset. There may also be complaints of episodic bleeding or drainage from the cutaneous site with persist- ence of the cutaneous lesion. Occa- sionally, there is a history of injury to the tooth. Correct diagnosis of the cutane- ous sinus of dental origin should be suspected by the gross appearance of the lesion. These cases typically present as erythematous, symmetri- cal, smooth, non-tender nodules of one to 20 mm in diameter with crust- ing and periodic drainage in some cases. The most characteristic feature of the nodule is its depression or re- traction below the normal surface. This cutaneous retraction or dimpling is caused by the fixation of the tract to the underlying tissues and may be secondary to the healing process or a late finding in active disease. Lesions that previously underwent biopsy and treatment are usually characterised by the absence of at least part of the nodule and frequently by an orifice of draining sinus at the base of the fixed depression. Endodontic infection, the prod- uct of cellular degeneration—bacte- rial toxins—and, occasionally, the bacteria themselves within the canal spread through the apical foramen into the surrounding tissue. Thus, a slow inflammatory process begins in the tissue contained within the peri- odontal ligament. Left to itself, it may manifest in a variety of ways, ranging from simple widening or thickening of the ligament to granuloma or cyst. Sometimes a fistula may develop, with the patient reporting intermittent dis- charge of pus. The fistula provides a means of continuous drainage of the lesion. The opening of the fistula may be found on the mucosa overlying the tooth that sustains it, but often it may also be found at a considerable distance from the diseased tooth. In some cases, the fistula may run in the space of the per- iodontal ligament of the same tooth. It may even traverse the periodon- tal ligament of the adjacent healthy tooth, thus simulating a lesion of peri- odontal origin. In such cases, negative pulp tests performed on the crown of the tooth, indicated by a gutta-percha cone inserted into the fistula, assist in making the correct diagnosis. If the drainage of the fistula is not continuous but intermittent, it is pre- ceded by a slight swelling of the area as a result of the increased pressure of pus behind the closed orifice. When the pressure becomes strong enough to rupture the thin wall of soft tissue, the suppurative discharge issues ex- ternally through the small opening of the fistulous orifice. This orifice may heal and then re-close, only to re-open later. The discharge of pus is never accompanied by intense pain. At most, the patient will complain of slight soreness in the area prior to reopening of the external orifice. The pus creates a tract in the surrounding tissues, following the locus minoris resistentiae. It may exit, at any point, in the oral mucosa or even in the skin. It is not uncommon, particularly in young patients, to find a cutaneous fistula at the level of the mental sym- physis, if lower incisors are involved, or in the sub-mandibular region, if a lower first molar is involved. Also, it may be found in the floor of the nasal fossa, if a central incisor is involved. Attempts to treat cutaneous fis- tulae with a circular incision of the orifice of the cutaneous fistula and excision of its entire tract with all the ramifications cannot be considered to comply with the present standard of care and should be regarded as highly undesirable. Most of the time, root canal therapy is the ideal treatment for such lesions. However, Gross- man states that such tracts are lined by granulation tissue. In his study, Grossman was unable to identify any epithelium at all. Bender and Seltzer also conducted histological studies of numerous fistulous tracts without finding an epithelium lining. Given the current state of knowledge and scientific data, there is no reason to recommend surgical removal of such tracts, just as there is no reason to be- lieve that even epitheliumlined fistula tracts should not heal after appropri- ate endodontic therapy. Obviously, these fistulae must be distinguished from congenital fistulae of the neck, both lateral-arising from the second brachial cleft—and medial— arising from rests of the thyroglossal duct—which are lined by an epithe- lium. Such fistulae are of a different pathogenesis and definitely do not resolve spontaneously but only after careful surgical excisions of the tract. Cutaneous sinus tracts: An endodontic approach Diagnosis and treatment for a successful outcome Fig. 1_Post-op photo one week after external surgery to remove the pa- tient’s sub-mandibular gland. Fig. 2a_Panoramic X-ray showing some bone rarefaction under teeth 47 and 46. Fig. 1 Fig. 2a The differential diagnosis of the case in question included the following: • localised infection of the skin, such as pyoderma, pimples, in- grown hairs and obstructed sweat glands; • traumatic or iatrogenic lesions; • osteomyelitis; • tuberculosis; and • actinomycosis. Case presentation The patient was referred to me from overseas with a large man- dibular fistula, which had previ- ously been misdiagnosed as an infection of the sub-mandibular gland. Surgery had been per- formed and his submandibular gland had been extracted. The woundhad not healed and the clinical situation was fast worsen- ing. Thus, the wound had opened and subinfected with a heavy dis- charge of pus. A dentist invited to see the pa- tient immediately telephoned me and sent a photo of the wound to me via his mobile phone. Fol- lowing my recommendation,the patient was immediately put under double antibiotic therapy (Amoxicellin 1000mg twice dai- ly, Metronidazole 500mg twice daily). The patient presented to my clinic the following day, where we started with a detailed questionnaire to collect all the information about the history of the wound. The patient reported that he had been suffering from this fistula for quite some time already with intermittent phases of discharge of an exudates and numbness of the lower lip. No dental pain was reported. A panoramic X-ray showed some bone rarefaction under teeth 47 and 46, but no invasion of the mandibular nerve tract was evident (Fig. 2a). A dental scan with 0.5 mm increment was performed in order to gain a bet- ter idea of the clinical situation. One of the sagittal slides (013) clearly shows the lesion around the distal root of tooth 47, sur- rounding the apical part and de- stroying the cortical bone invad- ing the lower soft tissue (Fig. 2b). Furthermore, the mesial root of tooth 46 showed apical radiolu- cency, invading the tract of the lower mandibular nerve (014; Fig. 3). This pathology explains the numbness of the lower lip, while the pathology around the distal root of tooth 47 explains the extra-oral fistula. Careful review of the axial slides in the area of tooth 47 (006) offers an idea about the amount of bone destruction in the lower lingual area. The axial slide un- der tooth 46 reveals the com- munication between the lesion under the mesial root and the mandibular nerve tract (Fig. 4). Next, we established a clear diagnosis that the lesion was an extra-oral cutaneous fistula of dental origin. The patient was suffering from a large, infected open wound and a suitable treat- ment plan had to be established quickly. The following solutions were presented: 1. Extraction of the teeth and curettage of the area, with extra attention paid to the mandibular nerve: This plan could provide the patient with a solution for eliminating the infection and al- lowing the wound to heal. Yet, two strategic molars would be lost with this solution and a re- placement would not be an easy job with this amount of bone de- struction in the infected area. 2. More conservatively, a root canal treatment in order to clean and disinfect the root canal sys- tems of the two molars, followed by an internal medication and a 3-D obturation capable of block- ing the bacteria from reaching the apical part and trapping the remaining bacteria inside the root canal system: This approach would allow the patient to keep his molars and would provide an environment in which the heal- ing process could begin. The risk would be the establishment of an external biofilm that cannot heal by itself and may require micro- surgical removal. The patient and I decided to preserve the two molars. Immediately, root canal treat- ment, cleaning and shaping of the canal space using TF files (Sybron- Endo) with copious and alternate irrigation of Chlo- rhexidine, SmearClear (Sybro- nEndo), distilled water, and sodium hypochlorite with ultra- sonic activation in a well-estab- lished sequence, was performed. An apical enlargement to size 40 in .04 taper was performed after crown down with K3 files (SybronEndo), to disturb the biofilm mechanically and to help reduce the colony formation unit (CFU). Media CME DENTALTRIBUNE Middle East & Africa Edition6 The article has been accred- ited by Health Authority - Abu Dhabi as having educa- tional content and is accept- able for up to 2 (Category 1) credit hours. Credit may be claimed for one year from the date of subscrip- tion. 2 Hours

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