ROEN0210

I 31 case report _ peri-apical microsurgery I roots2_2010 of pulp necrosis have a worse prognosis than cases with live pulp, as the presence of a large quantity of bacteria and the limitation of correctly eliminating them may lead to treatment failure. Failure to remove the fractured endodontic in- strument results in deficient cleaning, shaping and filling of the root-canal system. Under these condi- tions, in addition to the endodontic diagnosis, the time during treatment when the instrument fracture occurs is of great importance in the prognosis of the case.10 When instrument fracture in a contaminated canaloccursatthebeginningoftreatment,theprog- nosisisworsebecausethereisstillalargequantityof bacteria,andthepresenceoftheinstrumentmaypre- vent adequate microbiological control. The presence of the instrument may also contribute to inadequate endodontic filling. The prognosis is better when the fracture occurs near the end of the canal-cleaning andshapingprocess,asitisatamoreadvancedstage of endodontic microbiological control. In situations of instrument fractures associated with pulp vitality, the prognosis does not change significantly.10 _Removing broken instruments When making the decision to remove the instru- ment, factors such as pulp diagnosis, location, root curvature and length, size and type of fractured instrument, remaining dentinal thickness, and risks ofiatrogeniesduringtheattemptedremovalmustbe taken into consideration. A technique commonly used for removing frac- tured instruments is to achieve a bypass with a man- ualfile,sothatthefragmentcanbedrawntothepulp chamber and removed. Another removal technique is by means of ultrasonic vibration of the fractured fragment, associated with the use of an operating microscope. The application of ultrasonic energy causes the fractured instrument to vibrate, causing it to detach from the canal wall, and it can then be drawn to the pulp chamber and finally removed.7 The application of these methods in atresic canals may result in excessive wear of the root walls. There- fore, their use associated with the operating micro- scope is safer, owing to the possibility of improving visualisation through the magnification and illumi- nation provided by the microscope. Incasesofunsuccessfulremovaloftheinstrument andcontrolofinfection,withpersistenceofsignsand symptomsofendodonticdisease,surgicalremovalof the fragment may be indicated. Fig. 3_Initial occlusal clinical aspect. Fig. 4_Gutta-percha removal without solvents. Fig. 5_2.5% NaOCl. Fig. 6_After shaping. Fig. 7_After filling, with broken file still in place, and before micro-surgery.Fig. 7 Fig. 6Fig. 5Fig. 4Fig. 3