No abstract

All instrument movements were associated with apically extruded debris. However, the 150° CCW-30° CW and 270° CCW-30° CW reciprocating motions were associated with less extrusion than continuous rotation.

All the systems that were tested produced dentinal cracks. There was no significant difference between the control and F360 groups in terms of dentinal crack formation.

The aim of the present study was to compare the effects of ProTaper Gold, WaveOne Gold, ProTaper Universal, and WaveOne instruments on the amount of apically extruded debris. Eighty mandibular premolar teeth with straight root canals were selected and assigned to four groups (n = 20). The root canals were instrumented using ProTaper Gold, WaveOne Gold, ProTaper Universal, and WaveOne systems. Eppendorf tubes containing apically extruded debris were weighed three times, and mean values were calculated. The net mass of the extruded debris was calculated by subtracting the initial mass from the final mass. The groups were compared using one-way analysis of variance and Tukey's post hoc tests at a significance level of P < 0.05. The PTG group extruded less debris than the PTU group, and the WOG group extruded less debris than the WO group (P < 0.05). All the instrumentation systems tested in the present study were associated with apical extrusion of debris.

Aim:The aim of this study is to evaluate the root canal transportation, centering ability, and instrumentation times with the ProTaper Gold (Dentsply Tulsa Dental, Tulsa, OK, USA), Reciproc (VDW, Munich, Germany), and ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland) using cone-beam computed tomography (CBCT).Materials and Methods:Thirty mesial root canals of mandibular first molars with curvature angles of 35°–70° and radii of 2–6 mm were included in the study. Root canal instrumentation was performed up to F2 or R25. The instrumentation times were recorded. CBCT scanning was performed both pre- and post-instrumentation. Root canal transportation and the centering ratio were calculated for groups, and the data were analyzed using a one-way ANOVA and least significant difference post hoc tests for the instrumentation time, root canal transportation, and centering ratio at the 95% confidence level (P = 0.05).Results:At 3, 5, and 7 mm levels, there was no significant difference in the root canal transportation and centering ratio among the groups (P > 0.05). There were significant differences between the Reciproc and ProTaper Universal groups in the instrumentation times (P < 0.05).Conclusion:Root canal transportation and the centering ratio with the ProTaper Gold were similar to those obtained with the ProTaper Universal and Reciproc.

The aim of this study was to determine the bond strength of resin cement in root sections with or without butterfly effect. Fifteen single-rooted human maxillary central incisors were decoronated and prepared up to size 40. After post space preparation, the resin cement was placed into the post space and the fiber posts were luted. 1 mm thickness slices were obtained and the presence of the butterfly effect was recorded. A push-out test was then used to measure the bond strength between the resin cement and root dentin. Data were analyzed using independent samples of t and χ(2) tests (p = 0.05). The sections exhibiting butterfly effect showed higher push-out bond strength values than those of without butterfly effect (p < 0.05). Butterfly effect can influence the push-out bond strength. Thus, this phenomena should be taken into account, when push-out bond strength test is performed. Root sections exhibiting butterfly effect resulted in higher push-out bond strength values to root sections without butterfly effect.

Due to having thorough knowledge on the root canal anatomy and the variations will increase the success of the root canal treatment. Although its most common configuration of the mandibular second molars is having two roots and three root canals. This report presents the endodontıc treatment of a four rooted mandibular second molar, diagnosed with the assistance of cone beam computed tomography .