金属冠脉支架磁共振适用性检测方法

目的:建立金属冠脉支架磁共振适用性实验平台,以实验室测试为基础,研究金属冠脉支架的磁共振适用性。方法:金属冠脉支架磁共振适用性试验分为四个部分,在3T磁共振环境下,分别进行磁位移力试验、磁扭矩试验、致热试验和图像干扰试验。结果:退磁效果好的金属冠脉支架,磁位移力小于其自身重力,磁扭矩小于其自身重力扭矩,温度升高值小,图像畸变值小。退磁效果不好的支架,磁位移力大于其自身重力,温度升高多,图像畸变值大。结论:实验平台可以对金属冠脉支架磁共振适用性进行检测,并对其退磁效果进行评价。     

种植支抗非拔牙矫治成人上颌前突畸形的临床研究

目的：探讨种植支抗非拔牙矫治成人上颌前突畸形的临床疗效。方法分析50例上颌前突畸形成人患者临床资料,依据支抗不同进行临床分组,对照组(传统强支抗组)20例和观察组(种植支抗非拔牙矫治组)30例。结果观察组上颌前突患者上中切牙切缘到Y轴的距离(U1-Y)、下中切牙切缘到Y轴的距离(L1-Y)、上第一磨牙冠近中点到Y轴的距离(U6-Y)、下中切牙长轴和下颌平面所形成的后上夹角(L1-MP)、上、下中切牙长轴之间的夹角(U1-L1)优于对照组,差异均有统计学意义(P<0.05)。结论不锈钢微螺钉种植系统矫治成人上颌前突畸形效果明显,值得临床推广应用。     

Erratum: Author’s research-fund support notation correction. Mass forming chronic pancreatitis mimicking pancreatic cystic neoplasm: A case report World J Gastroenterology 2018; Jan 14; 24 (2): (297-302)

Correction to "Mass forming chronic pancreatitis mimicking pancreatic cystic neoplasm: A case report" World J Gastroenterology 2018; 24 (2): 297-302. This article had accidentally omitted the fact of research-fund support notation. It should be added as supported by Dankook University Research Fund (R201600314).     

基于一测多评法对丁蔻理中丸中6种成分的质量控制研究

目的:建立一测多评法同时测定丁蔻理中丸中白术内酯Ⅲ、白术内酯Ⅰ、丁香酚、6-姜辣素、8-姜酚、10-姜酚6种成分的含量。方法:以白术内酯Ⅰ为内标物,建立白术内酯Ⅰ与白术内酯Ⅲ、丁香酚、6-姜辣素、8-姜酚、10-姜酚之间的校正因子,计算待测成分含量,并将外标法测定值与一测多评法计算值进行对比,验证所建立一测多评法的准确性。结果:白术内酯Ⅲ、白术内酯Ⅰ、丁香酚、6-姜辣素、8-姜酚和10-姜酚分别在1.09~21.80μg·mL-1、0.71~14.20μg·mL-1、13.67~273.40μg·mL-1、6.04~120.80μg·mL-1、1.46~29.20μg·mL-1、1.78~35.60μg·mL-1范围内线性关系良好;各成分一测多评法计算值与外标法实测值无显著性差异。结论:利用校正因子对丁蔻理中丸中6种成分的含量测定是可行的,一测多评法可以用于丁蔻理中丸的质量评价研究。     

Multilevel modelling of longitudinal changes in isokinetic knee extensor and flexor strength in adolescent soccer players

The purpose of the study was to model the longitudinal development of knee extension (KE) and flexion (KF) strength in adolescent soccer players. A mixed-longitudinal sample composed of 67 soccer players aged 11.0–13.9?years at baseline was followed on three-to-five occasions over 5 years. Stature, body mass and several skinfold thicknesses were measured. Fat mass was estimated from skinfolds and fat-free mass (FFM) derived. Skeletal age was estimated with the TW2-RUS protocol. An isokinetic dynamometer was used to obtain peak torque of KE and KF from concentric assessments at an angular velocity of 180°/s. Multilevel random effects regression analyses were performed. Among youth soccer players aged 11–16?years, isokinetic strength of the knee muscle groups was reasonably predicted from chronological age (CA), stature and FFM: KE?=?–66.170?+?5.353?×?(CA)?+?0.594?×?(CA²)?+?0.552?×?(stature)?+?1.414?×?(FFM), and KF?=?–9.356?+?2.708?×?(CA)?+?1.552?×?(FFM). In conclusion, CA per se accounted for annual increments of 5.4?Nm in KE and 2.7?Nm in KF.     

基于ASTM F543-17标准测试的医用接骨螺钉旋动扭矩计算模型

目的研究医用接骨螺钉的旋动扭矩计算模型。方法分析自攻型接骨螺钉在旋入过程中的3个主要阶段,对螺纹形成阶段的扭矩与扭转角进行力学建模与模拟计算;同时,根据ASTM F543-17(YY/T 1506-2016)标准的要求,对来自3个厂家的规格均为φ2.9×12接骨螺钉在不同等级聚氨酯实验块上开展螺钉体外旋入实验,将实验结果与计算结果进行比较分析。结果理论模型所得与实验测得最大旋入扭矩偏差值分别为5、12 m N·m,小于实验测得扭矩的10%,在可接受的误差范围内。结论所开发的接骨螺钉旋动力学计算模型能够模拟并预测研发与临床应用中的旋动扭矩,结合体外扭动实验,能够为接骨螺钉的研发与设计提供一种有效途径。     

Comparison of the primary stability of orthodontic miniscrews after repeated insertion cycles:: An in vitro study

ObjectivesTo compare the primary stability of miniscrews after repeated cycles of insertion through insertion torque (IT) measurements and resonance frequency analysis (RFA).Materials and MethodsSixty titanium miniscrews were divided into two groups according to the insertion protocol: one with predrilled sites and the other self-drilled into porcine iliac crest bone specimens. Each group had three cycles of reinsertion. After each insertion, the IT and RFA were measured. The IT was measured by using a torque meter, and the RFA was measured using the Osstell ISQ device. A total of five miniscrews of each group were selected for sequential assessment of the morphology of their tip and threads using scanning electron microscopy after each insertion cycle.ResultsNo statistically significant differences were found in the IT values of miniscrews reinserted up to three times in the group with predrilled surgical sites. The IT value increased significantly with the number of reinsertions in the self-drilled group. The RFA value decreased as the number of insertions increased in both groups.ConclusionsUnder the conditions of this in vitro study, reinserting miniscrews deteriorates the integrity of their tip and thread. Reinsertion should be discouraged particularly when insertion sites are not predrilled.     

Comparison of Torque,Screw-in Force,and Shaping Ability of Glide Path Instruments in Continuous Rotation and Optimum Glide Path Motion

IntroductionThis study aimed to analyze torque/force generation and transportation in double-curved canals instrumented with 3 types of glide path files using optimum glide path (OGP) motion in comparison with continuous rotation.MethodsSixty simulated double-curved canals were prepared with #10/0.05 or #15/0.03 HyFlex EDM Glidepath files (Coltene/Whaledent, Altstätten, Switzerland) or a #13/0.04 prototype MANI Glidepath file (Tochigi, Japan) using OGP motion or continuous rotation (n = 10 each). Canals were sequentially prepared to 20 mm and 22 mm (full working length) using automated root canal instrumentation and a torque/force analyzing device. Transportation was calculated at 1–9 mm from the apex. Data were compared using 2-way analysis of variance followed by a post hoc simple main effect test with Bonferroni correction and a Kruskal-Wallis test (α = 5%).ResultsAll #10/0.05 instruments fractured. In the 22-mm preparation, the OGP motion resulted in lower clockwise torque and screw-in force than did continuous rotation (P < .05). In the 20-mm preparation, #15/0.03 instruments recorded a lower screw-in force for OGP motion than for continuous rotation (P < .05). Comparing the 2 preparation phases, OGP motion generated no significant differences; however, continuous rotation developed higher clockwise torque and screw-in force in the 22-mm preparation than in the 20-mm preparation (P < .05). There was no significant difference among the tested groups for transportation values.ConclusionsCompared with continuous rotation, OGP motion generated less screw-in force, lower clockwise torque, and similar transportation. The #15/0.03 HyFlex EDM instrument and the #13/0.04 prototype MANI instrument performed similarly well.     

Predicting transmitted irradiance through CAD/CAM resin composite crowns in a simulated clinical model

ObjectiveTo predict the clinically relevant transmitted irradiance that is available for luting when a CAD/CAM restoration is inserted. The influence of irradiance, exposure distance, light curing unit (LCU) angulation and direction of polymerization is analyzed when curing through crowns of different thicknesses.MethodsThree modern CAD/CAM resin-based composites (RBCs) were used to produce 45 crown-shaped specimens. The distance between fissure and crown base was set at 1.0, 1.5 and 2.0 mm (n = 5). Transmitted irradiance, while using a violet-blue LCU, was measured with a photo-spectrometer. 180 exposure conditions per specimen were investigated by variation in LCU curing mode, angulation, exposure distance and direction. Data was analyzed using univariate ANOVA followed by Tukey HSD (α = 0.05) and comparison of 95% confidence intervals.ResultsThe CAD/CAM-RBC’s decadic absorption coefficient ranges from 0.317 mm^?1 to 0.387 mm^?1 and the reflection correcting factor for crowns ranges from 0.305 to 0.337. Transmitted irradiance decreases significantly with increasing exposure distance and decreasing incident irradiance. For tilt angles greater than 10°, transmitted irradiances are significantly reduced (?11% for 20°, ?23% for 30°). Significantly lowest transmitted irradiances were measured for vestibular curing direction (up to ?15%).SignificanceA calculation model can predict the transmitted irradiance through a CAD/CAM restoration in dependence of restoration thickness and radiant emittance. The practitioner can be supported by this model to adapt material choice of dental restoration and adhesive system to the individual situation. Variation in exposure conditions shows negative effect on the transmission of light and should be limited.