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Objective @#To compare the shaping ability of 3 different nickel (Ni)-titanium (Ti) systems in simulated root canals in resin and to provide a reference for clinicians.@*Methods@#Forty-eight resin blocks were prepared using the F360 (Komet, Brasseler GmbH & Co., Lemgo, Germany) (Group 1), F6 SkyTaper (20/06) (Komet, Brasseler GmbH & Co., Lemgo, Germany) (Group 2), F6 SkyTaper (25/06) (Komet, Brasseler GmbH & Co., Lemgo, Germany) (Group 3) and Reciproc R25 systems (VDW, Munich, Germany) (Group 4) (n=12 canals/group). The images taken before and after preparation were superimposed and analyzed by Adobe Photoshop v7.0. The amount of resin removed by each system was measured, and the centering ability was assessed. The data were statistically analyzed using SPSS 20.0.@*Results @#At the 1 mm point, the transportation in Group 4 [(0.10 ± 0.03) mm] was significantly greater than that in Groups 2 [(0.05 ± 0.03) mm] and 3 [(0.05 ± 0.03) mm] (P < 0.05). At the 8 mm and 9 mm points, the transportation values in Group 4 [(0.12 ± 0.06) mm and (0.13 ± 0.05) mm] were significantly higher than those in Groups 2 [(0.05 ± 0.05) mm and (0.05 ± 0.05) mm] and 3 [(0.05 ± 0.04) mm and (0.06 ± 0.05) mm] (P < 0.05). At the 10 mm point, the transportation was significantly greater in Group 4 [(0.13 ± 0.06) mm] than in Group 2 [(0.06 ± 0.06) mm].@*Conclusion@#F6 SkyTaper exhibits better centering ability than Reciproc.
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Objective @#To compare the removal efficiency and the amounts of apically extruded debris using Twisted File (TF), Twisted File Adaptive (TFA), ProTaper, and ProTaper Next combined with ultrasonic irrigation and to provide an experimental basis for the selection of root canal instrumentation in the clinic.@*Methods@#Forty mandibular premolars were randomly divided into 4 groups (n=10 teeth per group). The canals were cut using a Twisted File, Twisted File Adaptive, ProTaper, or ProTaper Next nickel-titanium instrument. The canals were irrigated with ultrasonic irrigation. The apically extruded debris were collected in preweighted Eppendorf tubes. The amount of dental tissue removed and extruded debris were assessed with an electronic balance.@*Results @#The amount of tooth tissue removed in groups A, B, C and D was 20.5 ± 2.0 mg, 17.8 ± 4.2 mg, 20.8 ± 3.9 mg and 16.5 ± 2.2 mg, respectively. Combined with ultrasonic irrigation, the Twisted File and ProTaper had a better removal efficiency than the ProTaper Next(P < 0.05). There was no significant difference in the amount of extruded debris (χ2=4.057, P=0.255) among four groups.@*Conclusion@#The Twisted File and ProTaper had a better removal efficiency than the ProTaper Next combined with ultrasonic irrigation. There was no significant difference in the amount of extruded debris using four Nickel-titanium instruments combined with ultrasonic irrigation.
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The identification of expressed genes involved in sexual precocity of the mitten crab (Eriocheir sinensis) is critical for a better understanding of its reproductive development. To this end, we constructed a cDNA library from the rapid developmental stage of testis of E. sinensis and sequenced 3,388 randomly picked clones. After processing, 2,990 high-quality expressed sequence tags (ESTs) were clustered into 2,415 unigenes including 307 contigs and 2,108 singlets, which were then compared to the NCBI non-redundant (nr) protein and nucleotide (nt) database for annotation with Blastx and Blastn, respectively. After further analysis, 922 unigenes were obtained with concrete annotations and 30 unigenes were found to have functions possibly related to the process of reproduction in male crabs - six transcripts relevant to spermatogenesis (especially Cyclin K and RecA homolog DMC1), two transcripts involved in nuclear protein transformation, two heat-shock protein genes, eleven transcription factor genes (a series of zinc-finger proteins), and nine cytoskeleton protein-related genes. Our results, besides providing valuable information related to crustacean reproduction, can also serve as a base for future studies of reproductive and developmental biology.