|Year : 2012 | Volume
| Issue : 3 | Page : 161-164
Management of external cervical resorption using mineral trioxide aggregate
Badami Vijetha1, Janavathi Rangappa2, S Kranthikumar Reddy3, Nagaveni Aspalli1
1 Department of Conservative Dentistry and Endodontics, A.M.E's Dental College, Hospital and Research Centre, Raichur, India
2 Consultant Endodontist, ACPM Dental College and Hospital, Dhule, Maharashtra, India
3 Department of Conservative Dentistry and Endodontics, ACPM Dental College and Hospital, Dhule, Maharashtra, India
|Date of Web Publication||29-Apr-2013|
A.M.E's Dental College, Hospital and Research Centre, Bejengere Road, Raichur-584103, Karnataka
Source of Support: None, Conflict of Interest: None
External cervical resorption (ECR) is a relatively uncommon form of external root resorption, which may occur in any tooth in the permanent dentition. It is not well-understood or well-known in the dental community. Characterized by its cervical location and invasive nature, this resorptive process leads to progressive and usually destructive loss of the tooth structure. It is often misdiagnosed, leading to improper treatment or unnecessary loss of the tooth.
This article describes a case report of ECR and its management. The salient features were a large resorptive defect and localized fibrous growth located on the cervicopalatal aspect of maxillary right central incisor. Treatment included root canal therapy, surgical exploration, and restoration of the defect with mineral trioxide aggregate. The 1-year follow-up shows patient's tooth was asymptomatic and there was no evidence of progression of the resorptive process.
Proper diagnosis and appropriate treatment are the keys to a successful outcome in the management of ECR.
Keywords: External cervical resorption, invasive resorption, mineral trioxide aggregate
|How to cite this article:|
Vijetha B, Rangappa J, Reddy S K, Aspalli N. Management of external cervical resorption using mineral trioxide aggregate. Indian J Oral Sci 2012;3:161-4
|How to cite this URL:|
Vijetha B, Rangappa J, Reddy S K, Aspalli N. Management of external cervical resorption using mineral trioxide aggregate. Indian J Oral Sci [serial online] 2012 [cited 2020 Feb 19];3:161-4. Available from: http://www.indjos.com/text.asp?2012/3/3/161/111179
| Introduction|| |
Root resorption is the loss of hard dental tissue (i.e., cementum and dentin) as a result of odontoclastic action.  Root resorption of permanent dentition is usually unfavorable because it might result in irreversible damage and/or eventual tooth loss.
Root resorption might be classified by its location in relation to the root surface as internal or external resorption. External root resorption can be further classified into surface resorption, external inflammatory resorption, external replacement resorption, external cervical resorption (ECR), and transient apical breakdown. 
One of the least understood of the types of external resorption is ECR. This form of external resorption has been described at length by Heithersay, ,,, who preferred the term invasive cervical resorption, which describes its invasive and aggressive nature. Heithersay defined it as a relatively uncommon, insidious and often aggressive form of external tooth resorption, which may occur in any tooth in the permanent dentition. ECR usually occurs immediately below the epithelial attachment of the tooth at the cervical region. ,,
The exact cause of ECR is poorly understood. Cementum is considered to protect the underlying root dentin from being resorbed. It is broadly accepted that damage to or deficiency of this protective cementum layer below the epithelial attachment exposes the root surface to osteoclasts, which then resorb the dentin. The pulp plays no role in the etiology of ECR. 
The clinical presentation of ECR varies considerably depending on the extent of the resorptive process. The condition is usually painless and while a pink discoloration of the crown indicates the resorptive process, some teeth give no visual signs and diagnosis is usually the result of a routine or sometimes a chance radiographic examination. The lesions are rarely symptomatic but may be associated with bleeding from the inflamed and often proliferative tissue, which occupies the resorptive defect.
Radiographically the lesion classically presents as an asymmetrical radiolucency with ragged or irregular margins in the cervical region of the tooth. Early lesions may be radiolucent; however, more advanced lesions might have a mottled appearance caused by osseous nature of the advanced lesion. ,
It has been shown that conventional radiographic techniques reveal limited information on the true extent and nature of the resorptive lesion. Recently cone-beam computed tomography has been used to assess ECR lesions.  The position, depth in relation to the root canal and ultimately the restorability of the tooth can be assessed objectively before any treatment is carried out.
Treatment objectives to be considered when managing ECR are to arrest resorptive process, restore damaged root surface, prevent further resorption, improve esthetics of tooth (in cases where resorption has led to a pink spot). 
| Case Report|| |
A 45-year-old male patient reported with a chief complaint of discomfort and gingival bleeding in upper front teeth. The dental history revealed that the patient underwent orthodontic treatment about 25 years back and endodontic treatment of the maxillary right lateral incisor about the same time. No symptoms had been noted since then. His medical history was non-contributory.
Clinical examination revealed full dentate patient with discolored maxillary right lateral incisor. The labial and palatal gingiva was inflamed in relation to maxillary right central incisor. Probing revealed a pocket depth of 3 mm palatally, bleeding was observed and a fibrous sensation was felt. The tooth gave a negative response to thermal and electric pulp tests. Periapical radiograph revealed an irregular area of radiolucency in cervical region and also apical resorption with widening of the periodontal ligament space of the maxillary right central incisor and previous endodontic treatment of maxillary right lateral incisor [Figure 1]a. The resorptive radiolucency on maxillary right central incisor superimposed but did not alter the pulpal outline. A provisional diagnosis of apical inflammatory resorption associated with the necrotic pulp, and ECR was made associated with maxillary right central incisor.
|Figure 1: (a) Pre-operative radiograph (b) post-operative radiograph (c) elevation of palatal flap (d) exposure of resorptive defect|
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Because the tooth was non-vital, root canal therapy followed by surgery and restoration of the defect was planned. The patient was informed of the treatment plan, possible discomforts and potential risks before giving his consent to the treatment.
Root canal therapy was completed [Figure 1]b and the patient was scheduled for surgery.
Local anesthesia was administered; horizontal sulcular incision was made from distal of the maxillary right first premolar to the distal of the maxillary left canine. Palatal full-thickness mucoperiosteal flap was elevated [Figure 1]c. Granulomatous tissue within the defect area was carefully removed. Topical application of a 90% aqueous solution of trichloroacetic acid was done followed by further debridement to obtain smooth clean dentinal walls. Topical application of trichloroacetic acid results in coagulation necrosis of the ECR resorptive tissue, with no damage to adjacent periodontal tissues. The defect extended up to the middle third of the root of the tooth [Figure 1]d.The defect area was rinsed with sterile saline solution. The resorption site was subsequently restored with white mineral trioxide aggregate (MTA) [Figure 2]a. The flap was repositioned without tension and sutured interproximally with non-absorbable sutures [Figure 2]b and final radiograph was taken [Figure 2]c. After the surgery, the patient was prescribed antibiotics for 7 days, analgesics and 0.2% chlorhexidine mouth-wash 15 ml twice a day for 2 weeks. One week after the surgery, the sutures were removed. The healing was uneventful and the patient was symptom free.
|Figure 2: (a) Restoration of the defect with mineral trioxide aggregate (b) flap repositioned and stutured (c) immediate post-operative radiograph (d) after 1 year|
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At 1-year, recall tooth was asymptomatic, the probing depth was normal and there was no evidence that resorption had progressed [Figure 2]d.
| Discussion|| |
External resorption associated with inflammation in marginal tissues presents a difficult situation. Because the etiologies and treatment regimens for internal and external resorption are different, an accurate diagnosis is of paramount importance. Many times, lesions are misdiagnosed and confused with caries and internal resorption, resulting in inappropriate treatment. 
In ECR, probing the resorption cavity walls with an explorer, a hard, mineralized tissue sensation will be felt, accompanied by a sharp scraping sound. This feature and appearance of knife-edge cavity borders are important in the differential diagnosis with root caries. Sub-gingival caries will feel sticky on probing and also does not present with pink spot. Probing the ECR defect and/or the associated periodontal pocket will cause profuse bleeding of the underlying highly vascular resorptive tissue. 
A good radiograph is the key diagnostic tool in differentiating between internal and external resorption. The differential radiographic guidelines are as follows: The margins of the internal resorptive defect are smooth and well-defined, whereas the margins of the external resorptive defect are rough, have a moth eaten appearance and vary in density. Most internal resorptive defects are symmetrical, although, they may be eccentric. External resorptive defects are usually asymmetrical. With internal resorption, the root canal's anatomic configuration increases in size. In external resorption, the canal is unaltered and its outline can be followed through the resorptive defect unless the resorption is deep and has invaded the canal extensively.
A clinical classification of invasive cervical resorption has been developed by Heithersay to provide a clinical guide in the assessment of cases of invasive cervical resorption.  In the present case, the resorptive defect appeared to arise close to the epithelial attachment and showed extension into the coronal third of the root, thus it could be assessed as class 3 according to this classification. The study of potential predisposing factors showed that majority of patients presented at class 3 stage of resorption, which is indicative of the diagnostic difficulties encountered with this resorptive process.
Treatment depends on the severity, location, whether the defect has perforated the root canal system, and the restorability of the tooth. Several treatment regimes have been suggested in the literature, depending on the nature of the ECR 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.
Essentially, treatment involves complete removal of the resorptive tissue and restoring the resulting defect with a plastic tooth-colored restoration. Endodontic treatment might also be required in cases in which the ECR lesion has perforated the root canal. 
The surgical approach to treating cervical resorption has generally involved flap reflection, curettage, restoration of the defect with amalgam, composite resin, or glass-ionomer resin and repositioning the flap to its original position.
To treat the ECR lesions confidently, it is usually necessary to reflect a full-thickness periosteal flap to allow complete access and removal of the ECR lesion from the root, curetting away the granulomatous tissue from the adjacent periodontium to sever the blood supply to the resorbing cells, thereby decreasing the chances of recurrence. Ongoing bleeding from the cavity indicates that there is a blood supply apical or lateral to the cavity margin. The root defect can then be filled with composite resin or glass ionomer cement; the flap is then replaced.
Heithersay recommended topical application of a 90% aqueous solution of trichloroacetic acid, curettage and restoration with glass ionomer cement.  Topical application of trichloroacetic acid results in coagulation necrosis of the ECR resorptive tissue, with no damage to adjacent periodontal tissues.  It also infiltrates the small channels and recesses of ECR that would otherwise be unreachable by mechanical instrumentation. The trichloroacetic acid is very caustic and will cause burns if it comes in contact with gingival tissues. Dentin that has been treated with Trichloroacetic acid is severely demineralized and is not suitable for bonding with either dentin bonding agents or glass ionomer materials. It must be refreshed with a bur before bonding procedures. Dentin bonding agents rely on a shallow demineralization of the dentin surface, which is infiltrated with a resin to form a hybrid layer with the exposed dentinal collagen matrix. Glass ionomer materials rely primarily on ionic bonding to the calcium in hydroxyapatite. Trichloroacetic acid treated surface is demineralized to too great a depth for the dentin bonding agents to fully infiltrate, resulting in a weak, leaky bond. TCA almost totally eliminates the hydroxyapatite from the dentin surface, so there is no calcium available for bonding by glass ionomer materials. 
Periodontal reattachment cannot be expected with amalgam or composite resin and is unlikely with glass ionomer cement, but there is experimental evidence to suggest that this might be possible if MTA is used in this situation.
MTA has been shown to have good chemical and biological properties and its behavior has been investigated extensively in several clinical applications. , MTA has been shown to provide a long term release of calcium ions and can maintain a high pH for longer periods. Root resorption is shown to be arrested after placement of MTA. Recently, Bogern and Kuttler have advocated MTA obturation in complex and challenging endodontic conditions.
However, in the areas that will have constant contact with the oral flora, the MTA will be continuously contaminated. The development of sub gingival plaque could be promoted as a result of the rough surface of MTA. Because MTA is not a hard material, it could be partially scraped off during mechanical cleaning of the root surface.  MTA was used in this case because it has no constant contact with the oral flora. MTA was used because of its reported ability to provide a biocompatible surface for the possible adhesion/attachment of bone and cementum.
When discussing treatment options with patients, it is important to advise patients that the final decision on the treatment (surgical repair + endodontic treatment versus extraction) can only be objectively made once the full extent of the ECR is assessed, and this usually means surgical exposure of the ECR defect.
| Conclusion|| |
Proper diagnosis is essential for successful management and outcome of ECR. ECR can be arrested using the "Heithersay approach" to treatment, i.e., mechanical, debridement, treatment with TCA and restoration. MTA is a potentially useful material for repair.
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[Figure 1], [Figure 2]