DOI: 10.36347/sjds.2016.v03i05.002

Pages: 133-136

Abstract: The purpose of current study was to compare vertical root fracture(VRF) resistance of mandibular incisors and first molars following root canal preparation with hand k-file and Revo-S rotary file. 26 mandibular incisors(a1 and a2 subgroups) and 26 mandibular molars(b1 and b2 subgroups) were divided into 4 groups, each group contained 13 similar teeth. Crown of these teeth were cut off 2 mm to Cementoenamel junction and they were kept in distilled water. Root canals of a1 and b1 subgroup were prepared by hand files and canals of a2 and b2 sub groups were prepared by Revo-S rotary system. Then #35 spreader was pushed into root canals using instron testing machine until fracture happened and the force causing fracture was recorded. Data were analyzed using SPSS/PC 23 with one way ANOVA test. There was no significant relationship between occurrence of VRF and preparation instrument (P>0.05) but mandibular incisors showed less resistance to fracture than molars (P<0.05). Incisors and molars were mostly fractured mesiodistally and buccolingually respectively. Due to easier and faster instrumentation with Revo-S files and same fracture rate with hand files it seems reasonable to use these files, although mandibular incisors should be prepared gently and more carefully due to higher fracture rate.