PMC4731538_01
A) Suppurative fistula and defective PFM on tooth #22; B) Radiographic view of IRR; C and D) CBCT views of the tooth and adjacent bone destruction; E) Decrease of parulis size at the end of the second session due to irritants removal
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F1
On clinical inspection the tooth was slightly tender to percussion and a suppurating sinus tract was obvious on the buccal gingiva of the tooth (Figure 1A). Radiographic examination revealed a well-defined, rather oval radiolucency between coronal and middle thirds of the root (Figure 1B).  Cone-beam computed tomography (CBCT), was instructed and showed a perforating lesion leading to circular bone resorption with almost 7-8 mm diameter within the radicular bone (Figure 1C and 1D). The sinus tract was suppurative (Figure 1A). Elimination of tenderness on percussion, hemorrhage, discontinuation of suppuration through the sinus tract and decrease in the size of parolis confirmed the right time for obturation (Figure 1E). 
A-D) CBCT and radiographic views of CEM cement obturation, E) Cemented new all ceramic crown and the presence of sinus tract after one month
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F2
Tehran, Iran) was used for canal obturation. The whole canal space from apical constriction to 3 mm below the CEJ was filled with CEM cement which was carried into the canal with lentulo spiral (Dentsply, Maillefer, Ballaigues, Switzerland) and condensed with hand plugger (Figure 2A to D). After 1 month, the patient was asymptomatic, although the fistula was still present and the patient was unhappy with this situation (Figure 2E).
A) Periodontal flap to remove the granulation tissue and excess of the material; B) Immediate after surgery; C) 6-month follow up. Please note the progressing healing; D) One-year follow up showing complete healing
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F3
The granulation tissue, excess of CEM cement and the irregular borders of the perforation site were smoothened with a round bur (Thomas, Bourges Cedex, France) attached to an angulated surgical handpiece (Figure 3A). When the debridement was completed the flap was sutured with 7-0 nylon (Ethicon, NJ, USA) interrupted sutures (Figure 3B). After 6- (Figure 3C) and 12-month (Figure 3D) follow-ups, the patient was satisfied with the treatment from the esthetic point of view and also had no radiographic signs and clinical symptoms.