IntroductionThis study assessed the cleaning, shaping, and disinfection abilities of 2 instrumentation systems in molar root canals using a novel correlative analytical approach.MethodsThe root canals from extracted mandibular and maxillary molars with apical periodontitis were pair matched according to anatomic similarities as determined by micro–computed tomographic analysis and prepared with either XP-endo Shaper (FKG Dentaire, La Chaux-de-Fonds, Switzerland) (n = 16) or Reciproc Blue (VDW, Munich, Germany) (n = 16) instruments and 2.5% sodium hypochlorite irrigation. Pre- and postpreparation micro–computed tomographic scans were used to identify and calculate the unprepared surface areas (shaping), which were histobacteriologically evaluated for the presence of residual bacteria (disinfection) and pulp tissue remnants (cleaning) in each canal third.ResultsUnprepared canal surface areas for XP-endo Shaper and Reciproc Blue in the full canal length were approximately 26% and 19% (P < .05), respectively (30% and 23% in the apical part of the canal, P > .05). Preparation with Reciproc Blue resulted in 37.5% canals free of bacteria in all sections examined and 56% in the apical sections only. XP-endo Shaper resulted in 44% canals free of bacteria in all sections, and 56% in the apical part of the canal only. Pulp tissue remnants were not observed in 31% (all canal sections) and 50% (apical canal sections) of specimens from both instrument systems. No significant differences were observed between instruments when comparing the amount of pulp tissue remnants and the number of cases negative for bacteria and tissue remnants (P > .05).ConclusionsAlthough the Reciproc Blue instrument had superior shaping ability in comparison with XP-endo Shaper, both systems performed similarly in cleaning and disinfecting root canals. Irregular canals and difficult-to-reach areas were not thoroughly cleaned and disinfected by any of the tested systems. 相似文献
IntroductionThe aim of this study was to evaluate the amount of root canal dentin removed and apical transportation occurrence after instrumentation of mesiobuccal canals of maxillary molars with ProTaper Next (PTN [Dentsply Maillefer, Ballaigues, Switzerland]), OneShape (OS [MicroMega, Besançon, France]), and EdgeFile (EF [Edge Endo, Albuquerque, NM]) rotary systems.MethodsTwenty-seven mesiobuccal canals of maxillary molars were used. Canals were randomly divided into 3 groups for canal preparation: PTN, EF X3, or OS (n = 9 for each group). Micro–computed tomographic imaging was used to measure apical transportation (mm) and the volume of dentin removed (mm3). The amount of dentin removed was measured for the coronal portion and for the whole canal length. Superposition of pre- and postoperative cross-sectional apical slices were used to measure apical transportation at 1 mm from the apex; the differences were evaluated using the Kruskal-Wallis test and Wilcoxon analysis. The Spearman correlation coefficient was used to display the relationship between variables for each group. The significance level was set at P < .05.ResultsThe percentages of the amount of dentin removed on the coronal portion and the amount removed for the whole canal length were statistically similar between groups (P > .05). The average amount of apical transportation for the PTN, OS, and EF X3 were 0.197, 0.263, and 0.218 mm, respectively. Statistically, there were no significant differences between the 3 rotary instruments for apical transportation.ConclusionsThe amount of dentin removed for the coronal third portion and the whole canal length was similar for the PTN, OS, and EF X3 rotary instruments. Although there were differences in the sizes of apical enlargement, no apical transportation was observed in any of the instrumentation systems. 相似文献
Background:Arsenic trioxide (ATO) is widely applied to treat acute promyelocytic leukemia (APL). To elucidate metabolism and toxicity of arsenic, we analyzed time course of arsenic species in red blood cells (RBCs) of APL patients.
Methods:Nine APL patients received ATO (0.16 mg/kg/day) through 18-h infusion. Blood was collected before daily administration (days 2 to 9), and at different time points on day 8. Inorganic arsenic (iAs), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) were detected by HPLC-ICP-MS.
Results:Arsenic species reached Cmax at 18 h on day 8. Arsenicals gradually accumulated during days 2 to 9, whereas their percentages remained almost constant. The general trend in red blood cells (RBCs) was iAs > MMA > DMA. MMA was consistently the predominant methylated arsenic metabolite in RBCs. iAs, MMA, and tAs (tAs = iAs + DMA + MMA) concentrations (P < 0.0001), MMA/DMA ratios (P = 0.0016) and iAs% (P = 0.0013) were higher in RBCs than in plasma.
Conclusions:Time course of arsenic species reveal kinetic characteristic of ATO metabolites in RBCs. Arsenic species accumulated with administration frequency. Arsenic species in RBCs were remarkably different from those in plasma. Time course of arsenic species in RBCs is important in ATO clinical application. 相似文献