Apical extrusion of debris in root canal preparation leads to periapical inflammation and postoperative pain. The root canal preparation system affects the amount of extruded debris. On the other hand, reducing treatment time in pediatric dentistry is very important to improve behavior management. This study set out to compare the apical extrusion of debris and root canal preparation time of primary mandibular second molars using hand files, Mtwo, Reciproc, and Gentlefile rotary systems. In this experimental in-vitro study, 80 roots of primary mandibular second molars were randomly divided into four groups (n=20).The mesiobuccal canals were instrumented with hand files, Mtwo, Reciproc, and Gentlefile, and the preparation time was recorded. The extruded debris was collected in previously weighed Eppendorf tubes and desiccated in an incubator at 70°C for five days. The weight of the desiccated debris from each sample was calculated. Data were analysed using one-way ANOVA followed by the post-hoc Tukey's test for pairwise comparisons.Apical extrusion of debris and preparation time were significantly higher in the hand file group. Gentlefile caused minimal extrusion of debris with the shortest preparation

Debris Extrusion, Root Canal Preparation Time, Mtwo, Reciproc, Gentlefile