One week after the emergency visit, the patient attended the endodontist, with only little symptoms from the tooth 12. The crown was penetrated with a diamond (ceramic) and hard metal (metal part of the crown) burs and some dentine was removed with a round steel bur at low speed. Operative microscope was used to localise the position of the previous canal, as secondary dentine usually shows a clearly different structure and colour under stereo microscope. A long size 010 round bur was used to penetrate deeper. At 13 mm the canal was reached and instrumented first with size 008 and 010 K-files, used with balanced force and filing techniques. After this the canal was prepared with mechanical (Profile) preparation to size 40, and manually instrumented to size 50 apically. Calcium hydroxide was applied into the canal, which was then sealed with IRM filling.

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