牙齿漂白的机理及最新研究进展

牙齿漂白是二十一世纪牙齿保健的主要议题,随着漂白方法及药物的不断更新,漂白效果也在日益完美,现将牙齿漂白的机理及最新研究进展做一综述.     

正畸拔牙患者牙科焦虑症的调查及分析

目的调查正畸拔牙患者拔牙前的焦虑状况,为术前进行心理治疗和心理护理提供指导。方法采用改良Corah牙科焦虑量表（DAS）对270例患者进行调查和统计分析。结果明显患有牙科焦虑症的患者占18.52%（DAS评分值≥13）。结论正畸拔牙患者拔牙前的焦虑状况普遍存在,医护人员应对焦虑患者采取必要的术前心理治疗和护理。     

定子斜槽的混合励磁永磁同步发电机研制

在混合励磁永磁同步发电机基础上,研制了定子斜槽混合励磁永磁同步发电机。仿真结果表明:定子斜槽混合励磁永磁同步发电机可以动态实时输出功率,具有很小的电压调整率,可实现全自动调压,过载能力强,输出电压波形正弦畸变率低,不同负载之间相互干扰和影响降低到最低限度,供电品质显著改变,供电系统可靠性大大提高。     

新时期师德培育路径的机制安排

新时期师德培育路径,可选择如下机制安排:建立教学管理环节上的主、被动平衡机制、建立考核互评机制、彻底废除职务无限任期制。     

基于RBF神经网络和积分型高阶滑模控制的永磁同步电机位置伺服系统

本文主要研究永磁同步电机伺服系统的位置跟踪问题。根据矢量控制原理,针对d轴电压,设计了一阶滑模控制器,将使d轴电流在有限时间到达0。针对q轴电压,基于滑模控制理论,设计了积分型高阶滑模控制器。由于系统中存在不确定性参数,设计了基于神经网络的q轴电压滑模控制器。理论分析表明,在所设计的控制器作用下,可以保证位置系统的精确跟踪控制。仿真结果表明了该控制方案具有较好的收敛性和抗干扰性能。     

Effect of Dental Course Cycle on Anatomical Knowledge and Dental Carving Ability of Dental Students

This study assessed the effect of the course cycle on theoretical knowledge of dental morphology and the dental carving ability of dental students. Thirty-two dental students from the third semester (initial cycle) and 30 students from the eighth and tenth semesters of the dental course (end cycle) had their theoretical knowledge on dental morphology assessed using a questionnaire with ten closed questions. Their dental carving ability was also assessed using wax carvings in macro models of plaster (for the third [S3] and eight [S8] semesters) and natural-sized artificial teeth (for the tenth [S10] semester). The teeth chosen for the dental carving activity were #16 and #47. The scores were statistically analyzed using the t-test, Kruskal–Wallis test, and Mann–Whitney test (α = 0.05). Students from the initial cycle presented better theoretical knowledge than the other groups did (P < 0.007). No significant differences in carving score were found between the initial and end cycles (P > 0.05), although S10 students obtained a higher score for teeth #16 and #47 (P < 0.05). Natural-sized artificial teeth received a higher evaluation score in dental carvings than the macro models (P < 0.001). Within the limits of this study, it was possible to conclude that students from the initial cycle (S3) presented higher theoretical knowledge, whereas no difference in carving ability was observed between the initial and end cycles. The tenth semester (S10) students performed dental carvings with better quality. Furthermore, carvings in natural-sized artificial teeth presented better quality compared with the macro models.     

Three-Dimensional Tooth Models with Pulp Cavity Enhance Dental Anatomy Education

Dental anatomy is an integrated, core fundamental dental course, which prepares students for all future clinical dental courses. This study aimed to build up an online dental learning platform of micro-computed tomography-based three-dimensional (3D) tooth models with pulp cavity, and to further evaluate its effectiveness for dental anatomy education using a cohort study. First, ninety-six extracted permanent teeth were scanned by micro-computed tomography and the enamel, dentine, and pulp cavity of each was distinguished by different grey-scale intensities using Mimics software. Three-dimensional images allowed further discrimination and insights into permanent three-rooted premolars, central tip, and dental diseases including deep caries and wedge-shaped defects. Furthermore, a second mesiobuccal canal (MB2) in maxillary permanent molar teeth and Vertucci type III root canal configuration in mandibular anterior teeth could be detected using the 3D analytical tool. A digitized 3D tooth model learning platform was implemented. Last, two groups of dental students were assessed to evaluate the effect of 3D models on dental anatomy education. Participants in the Digital group were allowed to use the online dental learning platform freely after class, while the participants in the Traditional group were not. Assessment quizzes showed that participants' scores improved in the Digital group with the use of the learning platform compared with scores in the Traditional group. A questionnaire survey indicated that the participants had a positive attitude toward the 3D models. Thus, adding digital 3D resources to a traditional curriculum may have a positive effect on academic achievements.     

永久钢井架凿井的改进

在立井井筒建设中，我们在原设计的基础上，对箱形永久钢井架凿井的实际方法作了改进。这样既能发挥原设备的功能，又缩短了工期；降低了成本，提高了工效。     

后牙改良式粘接桥的临床应用(附42例报告)

目的观察后牙改良式粘接桥的临床效果。方法对42例后牙缺牙进行改良式烤瓷粘接桥修复。对其进行1～2年临床观察。结果42例后牙改良式粘接桥固位好。无继发龋，无基牙松动。结论只要严格掌握适应症，后牙改良式粘接桥临床效果可靠。     

年轻恒前牙外伤脱位的治疗

目的：观察年轻恒前牙外伤脱位的治疗效果，方法：对脱位牙进行常规复位，固定，对后期出现的根尖周炎，外伤性吸收进行碘仿氢氧化钙根尖诱导成形术，待根尖孔闭合后改用永久性根管充填，用X线片作疗效评估，结果：大部分病例能取得有效愈合，有效率为88．7％，结论：对外伤脱位的年轻恒前牙可通过复位，固定，根尖诱导成形术等来保证患牙。