Objective: To compare the effect of preoperative administration of an antihistamine, an analgesic, or a pla- cebo on postoperative pain in maxillary molar teeth with symptomatic apical periodontitis.
Design: A randomized, controlled trial.
Methods: Population: A total of 51 patients with moderate-to-severe maxillary molar tooth pain who have undergone a root canal treatment.
Intervention: Preoperative administration of either an antihistamine or an analgesic.
Control: Versus placebo
Outcomes: Reduction in postoperative pain? The data were analyzed with chi-square, one-way analysis of variance (ANOVA) and least significant difference (LSD) post-hoc tests.
Results: At days 1 and 3, preoperative administration of the antihistamine and analgesic resulted in lower pain levels than the placebo. At days 5 and 7, however, while preoperative administration of the antihista- mine still resulted in less pain than the placebo, there was no significant difference between the analgesic and placebo (P>0.05).
Conclusion: Within the limitations of the present study, the preoperative administration of an antihistamine can be beneficial in reducing the postoperative pain of endodontic treatments.

Objective: The aim of the present study was to compare the effects of EasyClean (EC) on irrigant delivery into simulated lateral canals using an artificial closed canal system. Passive ultrasonic irrigation (PUI) was used as a reference technique for comparison.
Materials and Methods: Forty simulated curved root canals manufactured in transparent resin and with sim- ulated lateral canals were instrumented with Reciproc R40 files and randomly assigned to four groups (n = 10) according to the irrigant activation technique: PUI group, ECrec group (EC used in reciprocating motion), ECrot group (EC used in rotary motion), and control group (no activation performed). After activation, stereomicro- scope images from each block were taken, and irrigant penetration into lateral canals was measured using Adobe Photoshop software. Data were analysed using ANOVA and Tukey’s post hoc test (α = 0.05).
Results: No penetration was observed in the control group. The ECrec group showed lower penetration than the other group (P<0.05). No differences were observed between the ECrot group and the PUI group (P>0.05). Conclusion: EC used in rotary motion was effective in increasing the penetration of the irrigating solution into simulated lateral canals.

Objective: To evaluate the bacterial extrusion during instrumentation with different nickel titanium (NiTi) engine-driven instruments.
Methods: Ninety extracted single-canal human mandibular incisor teeth were inoculated with Enterococcus faecalis to obtain biofilm formation and were randomly divided to 6 groups (n=15). One group served as the control and was not instrumented; the other groups were prepared with ProTaper Gold (PTG; Dentsp- ly Maillefer, Ballaigues, Switzerland), WaveOne Gold (WOG; Dentsply Maillefer), Twisted File Adaptive (TFA; SybronEndo, Orange, CA, USA), One Shape New Generation (OSNG; MicroMega, Besancon, France), and K3XF (SybronEndo) instruments. Bacteria extruded beyond the apical foramen were quantified in colony-forming units per milliliter. The number of colony-forming units in the remaining biofilm was determined for each sample. Data were analyzed using the one-way analysis of variance (ANOVA) and Tukey post-hoc tests. Results: All NiTi instruments resulted in different quantities of bacterial extrusion. The TFA group caused most bacterial extrusion (p<0.05). The PTG and WOG groups caused less bacterial extrusion than the OSNG and K3XF groups (p<0.05), but there was no statistically significant difference between the PTG and WOG groups (p>0.05).
Conclusion: PTG and WOG are preferable system in terms of successful endodontic treatments. The amount of bacterial extrusion is associated with the metallurgy and design of the instrument used.

Objective: The present study aimed to evaluate the bending resistance and cyclic fatigue fracture resistance of a new single-file reciprocating instrument called WaveOne Gold. Reciproc and WaveOne instruments were used as references for comparison.
Methods: Sixty 25-mm NiTi instruments (Reciproc R25, WaveOne Primary and WaveOne Gold Primary) were tested. Flexibility was determined by applying 45° bending tests using a universal testing machine (n=10). A custom-made device was used during cyclic fatigue test (n=10), comprising a stainless steel artificial ca- nal measuring 1.4 mm in diameter, 19 mm in total length with an 86° angle and 6 mm radius of curvature. Possible deformations at the helical shaft and mode of fracture were evaluated using scanning electron mi- croscopy analysis. Statistical analysis was performed using one-way analysis of variance. Post hoc pair-wise comparisons were performed using Tukey’s test for multiple comparisons (P<0.05).
Results: WaveOne presented significantly higher bending resistance than the other tested systems (P<0.05), whereas Reciproc presented the lowest bending resistance (P<0.05). Reciproc revealed a significantly longer cyclic fatigue fracture resistance than the other systems (P<0.05).
Conclusions: Although WaveOne Gold presented higher flexibility than WaveOne, no differences in the resis- tance to fatigue were observed between both systems. The Reciproc files were more flexible and resistant to fatigue for the angle of curvature of 86° and 6 mm radius than WaveOne and WaveOne Gold files.

Objective: The aim of this investigation was to assess the nominal tip diameter, taper and true pilot tip length of three nickel-titanium (NiTi) rotary files before and after use.
Methods: Three brands of NiTi files of size 25.08 were evaluated: ProTaper Uni-versal (Dentsply Tulsa Special- ties, Tulsa, USA), Channels PT (Insight Endo for Henry Schein, Melville, NY) and ProTaper Gold (Dentsply Tulsa Specialties), with ten files from each brand (total n=30). Scanning electron microscope (SEM) images of the files at 50x magnification were acquired before and after the files were used on endodontic training blocks, and the images were analysed by two independent investigators using ImageJ software. The nominal tip diameter (D0), taper and true pilot tip length (measured as the distance from the advertised diameter size of the file to the tip of the file) were recorded for each file and were analysed for statistical differences using repeated measures of analysis of variance (r-ANOVA) and Tukey’s post-hoc test (P<0.05).
Results: The marginal means of the nominal size showed statistically significant differences between brands of the same size; statistically significant differences were also observed between the advertised sizes and the actual sizes (P<0.001). The mean taper values showed statistically significant differences from the advertised (p<0.001) sizes, except for the ProTaper Gold (P=0.023) group. The changes in the true pilot tip length before and after use were not statistically significant (P>0.05). The pilot tip lengths varied between brands.
Conclusion: All nominal tip diameters and most taper sizes of the analysed brands show statistically signif- icant differences from the nominal sizes advertised by the manufacturers. The differences in true pilot tip lengths between brands indicate a current lack of standardization.

Objective: To compare the cleanliness of oval cross-sectioned root canals after using different supportive techniques for removal of root canal filling material as part of retreatment process.
Methods: One hundred mandibular canine teeth with flat oval cross-sectioned canals were instrumented up to #40.06 and obturated using the warm vertical compaction technique. Removal of the gutta-percha and sealer was performed using the D-RaCe nickel-titanium retreatment instruments. The roots were random- ly divided into four groups of 25 teeth, and the activation processes were applied: XP-endo Finisher (XP), EndoActivator (EA) and IrrıSafe (IS). Conventional needle irrigation (CI) was used as the control group. The teeth were sectioned, and digital images were captured. The photographs were analysed using AutoCAD software regarding the area of residual root filling. Kruskal–Wallis and post hoc Dunn’s tests were performed for statistical analysis.
Results: There was significantly less gutta-percha and sealer remnant in the XP group than in the other groups (P<0.05). The CI group contained significantly more gutta-percha and sealer remnant than the other groups (P<0.05). The apical third of the CI group had significantly more residual gutta-percha and sealer when compared to that of the other groups (P<0.05).
Conclusions: Within the limitations of this study, the amount of gutta-percha and sealer in the XP group was lower than that in the EA, IS, and CI groups.