Impacts of different Nickel-Titanium rotary and reciprocating root canal preparation systems on the amount of apically extruded debris.

This study aimed to evaluate the amount of apically extruded debris caused by different NiTi files. One hundred mandibular premolars were included in this study. The specimens were divided into five groups (n = 20): (i) TruNatomy, (ii) WaveOne Gold, (iii) 2Shape, (iv) ProTaper Next and (v) Reciproc Blue. The extruded debris was collected into preweighed Eppendorf tubes. These tubes were weighed again, and the net weight of debris was calculated. Data were statistically analysed, and the significance level was set at 5%. The least amount of extruded debris was observed in the TruNatomy group (p < 0.05). Statistically significant differences were not found among (iii), (iv) and (v) groups (p > 0.05). However, these groups resulted in significantly higher amounts of debris when compared to (i) and (ii) groups (p < 0.05). The results lead us to conclude that all instrumentation systems caused apical extrusion of debris at varying weights.

Impacts of NaOCl and Irritrol irrigation solutions with/without autoclave sterilisation on the cyclic fatigue resistance of different nickel-titanium files.

This research aimed to examine the impact of NaOCl and Irritrol solutions with/without autoclave sterilisation on the cyclic fatigue resistance of ProTaper, WaveOne Gold and Reciproc NiTi files. Seventy files in every group were separated into seven subgroups (n = 10) according to irrigation solutions and sterilisation procedures. The mean and standard deviations of the time to fracture was calculated for each group, and the data statistical analysis was performed (P ≤ 0.05). Significantly higher cyclic fatigue resistance was found in Reciproc files than the other types of files. The differences between the control and other subgroups were found to be statistically insignificant (P > 0.05), except for subgroups 5 and 7 (P ≤ 0.05). Immersing NiTi files in NaOCl or Irritrol with sterilisation for three times considerably reduced the cyclic fatigue resistance of these files. Reciproc files exhibited the highest cyclic fatigue resistance in comparison with ProTaper and WaveOne Gold files.

Efficacy of Er,Cr:YSGG Laser with Different Output Powers on Removing Smear Layer After Retreatment of Two Different Obturation Techniques.

Objective: This study was designed to evaluate the effects of an Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet (Er,Cr:YSGG) laser on removing the filling residues and smear layer (SL) after retreatment using rotary files. Background: Er,Cr:YSGG laser has been proposed as an additional protocol to improve root canal cleaning and removal of the filling remnants. Methods: Eighty-four mandibular premolars were divided into six groups (n = 14). Groups 1, 2, and 3 were obturated using a cold lateral compaction technique, and groups 4, 5, and 6 were obturated using a thermoplasticized injectable technique. The retreatment procedures were performed in all of the groups using a rotary system before applying Er,Cr:YSGG laser at 1.5 W for groups 2 and 5, and at 3.0 W for groups 3 and 6. Then, the teeth were split longitudinally into two halves and observed under a stereomicroscope and a scanning electron microscope. The SL and residual filling materials were evaluated at the coronal, middle, and apical thirds of the root canal. The data were statistically analyzed using three-way analysis of variance and Tukey tests. Results: The 3.0 W Er,Cr:YSGG laser was significantly more effective in removing SL than the other retreatment procedures in the coronal and middle thirds, but there was no significant difference in the apical third (p > 0.05). However, carbonization was observed in some of the specimens in the 3.0 W laser groups. Conclusions: None of the retreatment procedures completely removed the filling remnants from the root canal. However, the additional use of lasers improved the canal cleaning after retreatment.