Aim:The aim of the present study was to compare in vitro the amount of debris extruded apically from extracted teeth, using Twisted files and ProTaper rotary during two different instrumentation systems. Materials and methods:Forty-five human single-rooted mandibular premolar teeth were randomly divided into three groups and contaminated with Enterococcus faecalis. The teeth in experimental groups were instrumented until reaching the working length with ProTaper rotary instruments and Twisted files with XSmart and XSmart Dual groups. Debris extruded from the apical foramen was collected into glass vials and the amount of bacteria was calculated. The data obtained were analyzed using Kruskal-Wallis one-way analysis of variance and Mann-Whitney U tests, with p = 0.05 as the level for statistical significance.

In the past, cases with open apices were often treated over several appointments, using calcium hydroxide, with the hope of creating a ‘‘calcific’’ barrier against which gutta percha could eventually be placed. The treatment could be as long and the prognosis is questionable. These roots were often thinner and, therefore, more brittle; extending treatment over a long period of time without providing a permanent restoration increased the chances of losing these teeth due to fracture. With the favorable histologic response of MTA, this material is the best current choice for this procedure. Completion of these cases in an effective and efficient way allows for permanent restorations to be done in a timelier manner, prolonging the longevity of these teeth. The following case report demonstrates the use of MTA as an obturating material to promote periapical healing with an open apex.