RESUMO
Various kinds of hand or rotary techniques are used for mechanical preparation of the root canal. The aim of this study was to assess the influence of the number of applications of conventional and two rotary instrumentation techniques [Profile, FlexMaster] on the apical extrusion of debris. In this study, 73 single rooted mandibular premolars with curvatures between 0 to 10 degrees were divided into three groups. Groups H, P and F were prepared by the hand step-back, Profile and FlexMaster techniques, respectively. Preweighed vials [0.0001 precision] containing distilled water were used to collect debris. After canal preparation, the vials were completely dried and weighed again. The weight of the debit extruded from the apical foramen was calculated by assessing the difference between the weights of the vials, before and after canal preparation. One-way ANOVA was used to compare the mean weight differences of the debris between the number of applications of the three different techniques. The weight of the debris varied significantly according to the number of times the Profile technique was applied [n=6], i.e. the quantity of debris decreased with increased application. A statistically significant difference was not observed between the number of applications using the other studied techniques. New Profile instruments induce more extrusion of debris from the apical foramen as compared to previously used instruments