ROEN0210

32 I I case report _ peri-apical microsurgery _A clinical example This article demonstrates the resolution of a cli- nical case in which there was fracture of a K3 rotary instrument in the apical third, extending out of the root apex. The patient, a healthy 44-year-old woman, came to the dental office complaining of constant, low intensity, spontaneous pain in the vestibular apical region of tooth #24, and presented intra-oral oedema, pain on chewing and vertical percussion. Shereportedhavingundergoneendodontictreat- ment in tooth #24 more than six years ago. In the peri-apical radiographic examination, it was possible to visualise deficient endodontic treatment and the presence of apical bone rarefaction (Figs. 1 & 2). An acute peri-apical abscess was diagnosed. Theproposedtreatmentwasendodonticre-treat- ment because in the previously performed treatment there was inadequate canal cleaning and shaping, which had led to filling with empty spaces and pro- longed the intra-canal endodontic infection. Peri- apical surgery was contra-indicated, owing to the presence of deficient endodontic treatment. Endodontic re-treatment began with access to the pulp chamber, with removal of the occlusal resin restoration, using ultrasonic diamond inserts (CR1, CVDentus;Fig.3).11 Fillingwasremovedfromtheroot canals with the use of ultrasound and type K hand files, without the use of solvents (Fig. 4). As auxiliary chemicalsubstances,2.5%NaOCl(Figs.5&6),ENDO- PTC and 17% EDTA-T were used. After removing the fillings from the canals and establishing the working length by means of the api- cal locator Elements Diagnostics (SybronEndo), root- canal preparation began with oscillating hand en- dodontic files in M4 handpiece up to type K #20 file. After this, preparation of the canals continued withK3SybronEndoVTVTPackfiles,drivenbyanNSK electric motor with torque control adjusted to 1.2N and a speed of 350rpm. At the time of using instrument K3 #30.04 in the apical region, there was no adequate control of the pre-established working length and the instrument overtook the root apex and fractured. The fractured fragment measured 3mm, of which approximately 1mm was outside of the apex. _The bypass technique Several attempts were made to remove the frag- ment using the bypass technique associated with the use of ultrasound and operating microscopy. In spite of making the bypass with a type K #08 file, and successively with type K#10, #15, #20 and #25 files, the fragment did not come out. The position of the instrument in the apical third, associated with the root curvature in the region, was responsible for the failed attempt to remove it. At this stage of the treatment, disinfection of the root-canal system had not yet been concluded. The presence of the instrument, made it impossible to sanitise the canals correctly and the signs and symp- toms of endodontic infection persisted. Inanendeavourtoperformadditionaldecontam- ination, calcium hydroxide was used as intra-canal medication for three weeks, but the signs and symp- toms of endodontic infection did not yield. As a result of the failure to control the infection in this case, complementary surgery was proposed to remove the apical root third, since it was not possible to shape and disinfect it because of the presence of the instrument. For the complete resolution of infection, the root canals were filled (Fig. 7) and after this, piezoelectric peri-apical microsurgery was performed to resect the apical third of the root. roots2_2010 Fig. 8e Fig. 8f Fig. 8a_Broken file, surgical view. Fig. 8b_Broken file, micro-mirror view. Fig. 8c_Retro view of obturation. Fig. 8d_Apical fragment. Fig.8e_Vicryl8-0sutures(operating microscopeat12.5xmagnification). Fig. 8f_Sutures (20x). Fig. 8a Fig. 8b Fig. 8c Fig. 8d