Tooth resorption part II - external resorption: Case series
A 12-year-old female patient was referred by a private practitioner who detected a mass of soft tissue on the palatal aspect of tooth 11. The patient had a history of alveolar cleft repair done about 1 year back. Clinical examination revealed an extensive soft tissue mass in a palatal defect of tooth 11 []. Gentle exploration revealed that besides loss of the palatal enamel there was also loss of enamel from the interproximal areas of the tooth. However, the labial surface of the tooth was intact. The tooth responded to thermal and electric pulp testing within normal limits. A periapical radiograph revealed a large irregular radiolucency in the coronal region of the tooth extending mesiodistally and slightly into the coronal radicular dentin []. A diagnosis of Class 2 external cervical resorption was made.\nGlycerol was applied to the adjacent tissues to form a protective film. Isolation was achieved using the cuff rubber dam technique. A small cotton pellet was then dipped in 90 percent trichloroacetic acid and the excess was removed by dabbing it on a piece of gauze. The cotton pellet was then applied over the resorptive tissue mass with gentle pressure for about 1 minute. The tissue mass underwent necrosis with repeated application of trichloroacetic acid which was curetted out till a sound dentinal base was revealed []. Care was taken to see that the interproximal areas of the tooth were thoroughly debrided. The cavity was then refreshed with a high speed bur and restored with glass ionomer cement [].\nTrichloroacetic acid is a chemical escharotic agent that causes coagulation necrosis and renders the resorptive tissue avascular.[] The use of trichloroacetic acid does not necessitate raising a flap to gain access to the lesion. This eliminates the possibility of active resorbing cells present in the flap from being repositioned over the repaired root surface.[] However, due to the caustic nature of the acid, certain guidelines need to be followed as outlined by Heithersay:[] a. The adjacent soft tissues should be protected with glycerol, b. A thin glycerol impregnated cotton roll should be placed into the gingival sulcus for added protection, c. The cuff rubber dam technique should be employed to prevent slippage of the acid impregnated cotton pellets into the oral cavity, d. Very small cotton pellets or mini applicators must be used and excess solution should be dampened on gauze, e. Tweezers used to carry the cotton pellets must not be used for other purposes during the procedure.\nA reduction of the microhardness in both dentin and enamel has been reported following the use of trichloroacetic acid.[] Hence, restorations that will reinforce the weakened tooth structure are recommended. Chemical adhesion to tooth structure favours glass ionomer cement as the restorative material of choice.[] Recently a ‘reverse sandwich restoration’ comprising of microfilled resin composite and resin modified glass ionomer cement has been proposed to overcome the hydrolytic instability of glass ionomer cement. The microfilled resin tends to flex with the tooth thus reducing the chances of debonding.[]\nTrichloroacetic acid etches dentin and enamel and hence, conditioning is not recommended prior to insertion of the glass ionomer cement.[] However, refreshing the tooth surface with a bur is necessary because dentin that has been treated with trichloroacetic acid is severely demineralised and is not suitable for bonding with either dentin-bonding agents or glass ionomer materials.[]