Decision was made on long term calcium hydroxide treatment for the tooth 34. After placing the rubber dam and surface disinfection, care was taken to localise a possible second root canal. Lingual canal was found and instrumented to size 40/21 mm. The previously prepared buccal canal was prepared to size 80/21 mm. Calcium hydroxide was packed into the canals for two months. However, the sinus tract did not disappear and a bacteriological sample was taken from the sinus tract. No growth was detected in the sample. The patient received also amoxicillin therapy with no effect.

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