Invasive cervical root resorption, also called as invasive cervical resorption (ICR) lesion, is a localized resorptive process that begins just below the epithelial attachment and above the ridge crest in the area of the connective tissue insertion. It is a silent yet aggressive type of external root resorption. In the early stages of ICR, the affected tooth remains asymptomatic until the resorptive process reaches the pulp and the patient present with pulpal and/or periapical symptoms. Clinically, it may appear as a defect just below the gingiva. Sometimes, it shows to a pink discoloration of the crown gingivally due to the extensive undermining of the enamel. Radiographically, in the early stages, it appears as well delineated to irregularly border mottled radiolucency.[2,3] In the late stages, there can be a mixed radiolucent and radiopaque appearance. This article elaborates a case report of surgical management of invasive cervical root resorption of mandibular canine using 90% trichloroacetic acid (TCA) and Biodentine as restorative material to seal the defect. Cone-beam computed tomography (CBCT), an important diagnostic tool for assessing the location and severity of the resorptive lesion, was used here.
A 40-year-old moderately built male patient came to the department with complaints of pain and swelling of the lower right front tooth region for 1 week. The pain was of sudden onset, the dull aching type which subsided on its own. The medical history of the patient was noncontributory. Dental history revealed fixed orthodontic treatment done 20 years back. Intraoral examination revealed generalized gingivitis and swelling of gingiva on the buccal aspect involving the vestibule in the regions of 43 and 45. Tooth number 44 and 34 were extracted for fixed orthodontic treatment. The tooth was tender on percussion and gave a negative response to cold testing. Radiographic examination of tooth number 43 showed an irregular radiolucency having a mottled appearance involving the coronal third of the root dentine that seemed to be merging with the radiolucency of the root canal space. Periapical radiolucency was also observed [Figure 1].
Axial CBCT sections at 0.15 mm revealed that the lesion was encircling the tooth at the lingual half, and at certain points, it was continuous with the root canal space [Figure 2]. Periapical radiolucency was also evident in the CBCT. According to the three-dimensional classification of external cervical resorption (ECR) by Patel et al., this lesion comes under the third category, which includes the lesion extending to the middle third of the root. Root canal treatment was planned as the case was diagnosed with pulp necrosis and symptomatic apical periodontitis. As the resorptive lesion was extensive, it was decided to close the defect surgically.
Access cavity was prepared on the lingual surface. After working length determination with #15 K-file (Mani, Tochigi, Japan) and apical enlargement up to size forty, cleaning and shaping was completed by the step back preparation. The canal was thoroughly cleaned and irrigated using 2.5% sodium hypochlorite alternating with saline. Calcium hydroxide was mixed with saline to form a paste and used as an intracanal medicament for two appointments which was scheduled at an interval of 2 weeks. In the third appointment as the patient was asymptomatic, obturation was carried out with gutta-percha using the lateral condensation method.
In the next appointment, surgical procedure for the closure of radicular defect was carried out [Figure 3]. A full-thickness mucoperiosteal flap was reflected from the lingual aspect extending from the mesial aspect of 45 to the mesial aspect of 41 after inferior alveolar and lingual nerve block. The granulomatous tissue present at the resorptive site was thoroughly excavated using a spoon excavator. All additional unsupported lips of the tooth structure were also removed. A small cotton pellet dipped in 90% TCA was applied with gentle pressure for the treatment of the cavity. The TCA taken on a cotton pellet was squeezed to remove the excess before the application on to the site, so as to prevent contact with the surrounding bone. This procedure of application of TCA and removal of necrotic tissue was carried out till a sound dentinal base was seen [Figure 4]. After excavation of the lesion, the gutta-percha was visible through the resorptive defect. After drying, the defect was restored with Biodentine (Septodont, Saint-Maur-des-Fosses, France) and was contoured according to the root curvature. The flap was repositioned and sutured to the position using 3-0 black silk suture material. Sutures were removed after 5 days, and radiographs were taken to assess the restoration. The patient was reviewed at 2 months and 6 months and was asymptomatic. The radiograph taken after 1 year showed satisfactory periapical healing and the resorptive defect merged well with the Biodentine [Figure 5].
ICR lesions are considered to be a diagnostic and management challenge due to its aggressive and haphazard behavior. Portal of entry (the area from where the resorptive process commences) is the cementum inferior to the epithelial attachment which may be damaged due to trauma or excessive orthodontic forces. In the presented case, orthodontic treatment was carried out 20 years back, and the patient does not remember any other history of trauma. Hence, the duration of the resorptive process was unknown as the patient was asymptomatic till it affected the pulp.
Any breach in the homeostatic balance between the osteoclasts and osteoblast cells will upregulate the osteoprotegerin system and down regulate the RANKL system. This will stimulate the resorptive process. Microscopically, the resorptive cavity contains granulomatous fibrovascular tissue with inflammatory cell infiltrates of lymphocytes, plasma cells, histiocytes, macrophages, and clastic resorbing cells. These cells will be placed adjacent to the dentin surface. It does not contain acute inflammatory cells. This will rule out the chance of infection as a primary etiology. The osteoclasts are derived from the blood macrophages. These are attached to the dentinal surface in resorption bays or Howship’s lacunae. Advanced lesions display fibro-osseous characteristics with deposition of ectopic bone-like calcifications.
Management strategy is to arrest the resorptive process by removing the resorptive tissue and blood supply to the existing odontoclasts and possible endodontic treatment in case of pulpal involvement. Several treatment regimens have been suggested depending on the nature of the lesion and are usually based on isolated case reports. These include intentional replantation, guided tissue regeneration, treating the ECR lesion by an internal approach only, and forced orthodontic eruption.
In this case report as the patient presented with pain and swelling, the endodontic treatment was carried out initially. Later, the lesion was explored surgically and to arrest the resorptive process 90% TCA was used. According to Heithersay, the topical application of aqueous solution of 90% TCA causes coagulative necrosis of the resorptive tissue only. The adjacent periodontal tissues are spared. These chemical escharotic agents get infiltrated into the small indentations formed by the resorptive process on the surface of the root that are otherwise be unreachable by mechanical instrumentation. This acid was used very carefully without touching the surrounding tissues as it is highly corrosive.
For restoring the defect, the most biocompatible and bioactive material available is mineral trioxide aggregate and its modifications such as Biodentine and Endosequence RRM. Biodentine is used in this case as it is fast setting (about <12min) and easier to handle. It acts as dentin replacement material and reinforces the tooth structure. It releases calcium and enhances the alkaline environment which is conducive for osteoblastic activity. Furthermore, the calcium and hydroxide ions stimulate the release of pyrophosphatase, alkaline phosphatase, and BMP-2 which stimulate mineralization process.
CBCT imaging overcomes the limitations of periapical radiographs, and this 3-dimensional imaging system has become increasingly important in the diagnosis and treatment planning of complex endodontic problems. This case report has put emphasize on the newer imaging modalities in the proper diagnosis of resorptive lesions in the inaccessible areas. Furthermore, the use of newer bioactive tricalcium silicate-based restorative materials has made the management of these aggressive resorptive lesions easier and more predictable.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
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