ROEN0310

34 I I case report _ instrument removal nostic radiograph (Fig. 1) showed not one but two broken instruments in the mesial root, one in each mesialcanal.Thereafter,thetoothwasisolatedwith therubberdamandthecoronalfillingwasremoved. Straight-line access was established, as this is im- perativeinordertobeabletoreachandseethefrac- tured instruments. Gates-Glidden burs (DENTSPLY Maillefer) were used to enlarge the mesial orifices coronally. Afterreachingtheinstrumentinthemesio-buc- cal canal, I modified a size 3 Gates-Glidden bur by removingthetipofthebur(Fig.2).Inthismanner,one gains an aggressive bur that allows one to create a platformabovetheinstrument.Atthismoment,the instrumentcouldbeclearlyvisualised(Fig.3).Ultra- sonics were then used to loosen the fragment. ProUltra tips (DENTSPLY Maillefer), both zirconium nitride and titanium, were used for this purpose. One-and-a-half hours after starting the treat- ment, the fragment had been loosened but was still stuckinthecanal.Wedecidedtoleaveitinplacefor the time being and made a new appointment. Calcium hydroxide paste(UltraCalXS,Ultradent)was put into the coronal part of the mesial canals and the tooth was sealed with glass-ionomer ce- ment (Fuji IX GP Fast, GC) and a cotton pellet. Duringthenextvisit,thetooth was again isolated and opened. The calcium hydroxide paste was removed, using 10 % citric acid and passive ultrasonics with the IRRISAFEtip(Satelec).Again,ultra- sonics were used to retrieve the instrument. After five minutes, the fragment in the mesio-buccal canal was removed. Another five minutes later, the instrument in the mesio-lingual canal was also removed. While removing the instrument in the mesio-buccal canal was very time-consuming, removing the instrument from the mesio-lingual canal was surprisingly easy. This clearly highlights the above-mentioned difficulty range of instru- ment retrieval. After the removal of both instruments, working length was determined in both mesial canals with the electronic apex locator (Root ZX Mini, Morita). A glide path was established and the mesial canals were initially shaped with a ProTaper S1 (DENTSPLY Maillefer). Copious irrigation was performed using 3% sodium hypochlorite. Next, the gutta-percha in the distal canal was removed with a size 25.06 ProFile (DENTSPLY Maillefer), which was rotated at 500rpm in an X-smart Easy endodontic motor (DENTSPLY Maillefer). No chemical was required for gutta-percha softening. The canals walls were Fig. 3_One of the separated instruments. Fig. 4_Gutta-percha cone fitting. Fig. 5_The pulp chamber after obturation with gutta-percha. Fig. 6_Final radiograph (parallel). Fig. 7_Final radiograph (angled). roots3_2010 Fig. 5 Fig. 6 Fig. 7 Fig. 4Fig. 3