磁力垫式矫治器的研制及临床应用

采用第三代稀土永磁体钕铁硼制成垫式活动矫治器。利用磁极间的排斥力,形成对上下颌后牙的压入作用,对前牙骨性开患者进行畸形矫治的临床应用研究,以期寻找前牙开畸形矫治的更佳途径。     

磁力He垫式矫治器的研制及临床应用

采用第三代稀土永磁体钕铁硼制成Ｈｅ垫式活动矫治器。利用磁极间的排斥力,形成上下颌后牙的压入作用,对前牙骨性开Ｈｅ患者进行畸形矫治的临床应用研究,以期寻找前牙开Ｈｅ畸形矫治的更佳途径。     

钕铁硼磁力矫治器的研制

目的 设计磁力扩弓矫治器并检验其性能,以确定临床应用的可行性。方法 钕铁硼永磁体经切割、镀铬,制作双轨滑动式磁力扩弓矫治器（ＭＥ１、ＭＥ２型）,测试其扩弓力、耐腐蚀性及每一磁体在矫治器上的更换通用性。结果 ＭＥ１、ＭＥ２矫治器最大扩弓力达４．３Ｎ及７．０５Ｎ,磁体耐腐蚀性能良好,磁体更换通用比率为９７．５％。结论 磁力扩弓矫治器性能良好。     

磁力(牙合)垫式矫治器的研制及临床应用

采用第三代稀土永磁体钕铁硼制成(牙合)垫式活动矫治器.利用磁极间的排斥力,形成对上下颌后牙的压入作用,对前牙骨性开(牙合)患者进行畸形矫治的临床应用研究,以期寻找前牙开(牙合)畸形矫治的更佳途径.     

两种不同临时冠材料的临床应用比较

目的：评价DMGLuxatemp临时冠材料（珞赛特）的临床应用效果。方法：将286例行固定义齿修复病例随机分成两组,牙体预备完成后分别用DMG Luxatemp临时冠材料和化学固化丙烯酸树脂临时冠材料（自凝塑料）制作临时冠,粘结完成后立即评价其边缘适合性、解剖形态、颜色和表面光滑度,10d后复诊再次评价其食物嵌塞情况、有无异味和牙龈状况。结果：DMGLuxatemp临时冠材料组各项满意率均高于传统的自凝塑料组,满意率差别有统计学意义（P〈0．05）。结论：DMGLuxatemp临时冠材料组总体效果优于传统的自凝塑料组。     

颊屏式双阻板磁力矫治器治疗下颌后缩畸形

目的：以磁力代替传统的机械力,结合功能矫治的基本原理,寻求治疗下颌后缩的更有效的方法与途径,方法：设计出一种新型的颊屏式双阴板磁力矫治器,对以下颌后缩为主要病因的AngleⅡ类Ⅰ分类错的混合牙列患者,进行了临床矫治研究。结果;治疗后显示上下颌在矢状方向的不调得到根本纠正,Ⅱ类关系改正,下面部垂直高度增加,侧貌凸面型明显改观。结论：颊屏式双阻板磁力矫治器能有效地诱导下颌前移,刺激下颌骨的生长及髁突的改健,同时也能起到掏上颌生长的作用。     

双阻板磁力功能矫治器矫治早期下颌偏斜的临床研究

目的探讨双阻板磁力功能矫治器（twin-block magnetic appliance,TMA）对替牙期和恒牙早期下颌偏斜的矫治效果。方法替牙期或者恒牙早期骨性下颌偏斜患者16例,其中男7例,女9例,平均年龄11岁,疗程TMA5~8个月,平均疗程TMA6个月。分析矫治前后的模型、面相和全景片,观察疗效。结果所有患者的下颌偏斜均有明显改善,颌位不调得以纠正,中线居中,颌面形态正常,效果满意。结论 TMA对替牙期和恒牙早期下颌偏斜的患者治疗效果明显,可以作为矫治下颌偏斜的方法之一。     

双阻板磁力矫治器矫治早期AngleⅢ类错

目的探讨双阻板磁力功能矫治器（ｔｗｉｎｂｌｏｃｋｍｅｇｎｅｔｉｃａｐｐｌｉａｎｃｅ,ＴＭＡ）对早期ＡｎｇｌｅⅢ类错的矫治效果。方法采用作者自己设计的ＴＭＡ对３２例生长发育期功能性骨性Ⅲ类错患者进行了矫治。通过Ｘ线头影测量、模型及面像分析,观察疗效。结果显示Ⅲ类面型获得明显改善,上下位不调得到纠正,颌面形态得到改建,疗效满意。结论磁力功能矫治方法对早期ＡｎｇｌｅⅢ类错有明显疗效。ＴＭＡ具有制作简单,结构小巧,容易测量和控制矫治力等优点。     

磁力矫治器矫治功能性Angle Ⅲ类错合

本文提出一种可摘式磁力矫治器设计，试用于替牙期功能性ＡｎｇｌｅⅢ类错　的矫治，取得肯定疗效，该设计不同于普通舌簧　垫矫治器，不通过改变切牙唇舌倾斜度以矫治前牙反　，而是利用磁力使下颌后退以改善颌间关系，上下颌矫治器的分体设计可增加矫治器戴用时间，较少影响口腔功能，克服了某些连体设计的功能性矫治器的缺点。     

两种阻萌器设计的临床应用研究

目的：比较传统带环丝圈式阻萌器和改良带环丝圈式间隙保持器在恒牙早萌病例的临床应用效果。方法选择40例6.5～8.5岁乳磨牙早失伴后继恒牙早萌的患儿,分别采用传统带环丝圈式阻萌器（传统组）和改良带环丝圈式间隙保持器（改良组）治疗,定期复诊观察至早萌恒牙牙根发育1/2以上,拆除矫治器,分别从患儿对阻萌器的制作、间隙保持情况、早萌牙健康状况等方面进行对比研究,并对测量数据进行统计学分析。结果两组在间隙维持和阻萌效果方面差异无统计学意义(P>0.05）,传统组患儿的早萌牙面龋发生率明显高于改良组(P<0.05）。结论改良带环丝圈式间隙保持器在恒牙早萌矫治中有效,且有利于龋病预防。     

Stress relaxation properties of four orthodontic aligner materials: A 24-hour in vitro study

Objective:To investigate the stress release properties of four thermoplastic materials used to make orthodontic aligners when subjected to 24 consecutive hours of deflection.Materials and Methods:Four types of aligner materials (two single and two double layered) were selected. After initial yield strength testing to characterize the materials, each sample was subjected to a constant load for 24 hours in a moist, temperature-regulated environment, and the stress release over time was measured. The test was performed three times on each type of material.Results:All polymers analyzed released a significant amount of stress during the 24-hour period. Stress release was greater during the first 8 hours, reaching a plateau that generally remained constant. The single-layer materials, F22 Aligner polyurethane (Sweden & Martina, Due Carrare, Padova, Italy) and Duran polyethylene terephthalate glycol-modified (SCHEU, Iserlohn, Germany), exhibited the greatest values for both absolute stress and stress decay speed. The double-layer materials, Erkoloc-Pro (Erkodent, Pfalzgrafenweiler, Germany) and Durasoft (SCHEU), exhibited very constant stress release, but at absolute values up to four times lower than the single-layer samples tested.Conclusions:Orthodontic aligner performance is strongly influenced by the material of their construction. Stress release, which may exceed 50% of the initial stress value in the early hours of wear, may cause significant changes in the behavior of the polymers at 24 hours from the application of orthodontic loads, which may influence programmed tooth movement.     

Learner-control vs. program-control instructional multimedia: a comparison of two interactions when teaching principles of orthodontic appliances

BACKGROUND: Many studies have compared computer assisted learning (CAL) to more traditional learning formats and have shown CAL to be as effective as or superior to the alternative resources. However, there are only scarce attempts to show which style of CAL leads to the best learning outcomes in orthodontics. AIM: To compare the effectiveness of a learner-control (group A) vs. program-control (group B) multimedia learning environment courseware packages regarding knowledge, understanding and transfer of content when applied to teaching principles of orthodontic appliances to undergraduate students. METHODS: Pre- and post-test assessments of undergraduate dental students (n = 30) who either studied a learner-control multimedia learning environment courseware package (n = 15) or a program-control version (n = 15) on equivalent material of the orthodontic appliances curriculum. Both groups were evaluated by means of multiple-choice questions covering knowledge, understanding and application. A one-way ANOVA was carried out in order to check for statistical difference between the two groups. The P-value was set at 0.05. Results: There was no difference in prior knowledge between both groups at baseline. Although, both groups significantly improved their scores after having studied the course, no significant difference was found between both groups in relation to answers to questions about knowledge, understanding and application. CONCLUSIONS: In this study, the learner-control instructional multimedia program was found to be as effective as the program-control version when teaching principles of the orthodontic appliances to undergraduate students. The focus needs to be on improving the value of CAL. Comparative evaluations of how different CAL approaches compare with or complement one another are certainly needed.     

两种不同材料的瓷嵌体用于后牙修复的临床效果比较

目的 比较在计算机辅助设计/计算机辅助制作(CAD/CAM)下IPS e.max全瓷高嵌体及LavaUltimate优韧瓷高嵌体用于修复后牙缺损的临床治疗效果。方法 临床完成IPS e.max全瓷高嵌体75个，LavaUltimate优韧瓷高嵌体62个，随访观察6个月、1年、2年、3年，参考美国公共健康会（USPHS）标准,对其临床效果进行观察。结果 IPSe.max全瓷高嵌体的颜色优于LavaUltimate优韧瓷高嵌体；而Lava Ultimate优韧瓷高嵌体的修复体完整性优于IPS e.max全瓷高瓷嵌体。结论 两种材料瓷嵌体用于后牙修复的临床效果没有显著差异，优选哪种材料取决于患者的喜好。关注修复体完整性的患者建议优选Lava Ultimate优韧瓷，关注高嵌体的颜色的患者建议优选IPSe.max全瓷。     

Clinical testing of restorative materials: some historical landmarks

Objectives: The aim of the study was to review the historical background of the methodologies currently in use for clinical investigations of contemporary tooth coloured dental restorative materials and techniques, and to attempt to identify the likely general direction of such research projects in the future.

Data sources: Published articles obtained as a result of a wide ranging literature search of both dental and medical journals.

Study selection: Historical and contemporary accounts of clinical trial management, upon which an overview of the key events important in the evolution of clinical methods of evaluation of dental restorative materials, and a prediction of possible future trends in this area, could be based.

Conclusions: Publication of dental restoratives clinical research has not kept up with that in medicine, where editors of leading journals require that clinical trials be run in accordance with the Consolidated Standards of Reporting Trials (CONSORT) guidelines. The current trend towards evidence based treatment in dentistry can be expected to initiate more statistically powerful clinical studies of dental restoratives, and the merit of involving general dentists in practice based research can also be anticipated to become increasingly recognised in the future.     

Pressure transmission area and maximum pressure transmission of different thermoplastic resin denture base materials under impact load

Purposes

The purposes of the present study were to examine the pressure transmission area and maximum pressure transmission of thermoplastic resin denture base materials under an impact load, and to evaluate the modulus of elasticity and nanohardness of thermoplastic resin denture base.

Evaluation and comparison of the marginal adaptation of two different substructure materials

PURPOSE

In this study, we aimed to evaluate the amount of marginal gap with two different substructure materials using identical margin preparations.

MATERIALS AND METHODS

Twenty stainless steel models with a chamfer were prepared with a CNC device. Marginal gap measurements of the galvano copings on these stainless steel models and Co-Cr copings obtained by a laser-sintering method were made with a stereomicroscope device before and after the cementation process and surface properties were evaluated by scanning electron microscopy (SEM). A dependent t-test was used to compare the mean of the two groups for normally distributed data, and two-way variance analysis was used for more than two data sets. Pearson''s correlation analysis was also performed to assess relationships between variables.

RESULTS

According to the results obtained, the marginal gap in the galvano copings before cementation was measured as, on average, 24.47 ± 5.82 µm before and 35.11 ± 6.52 µm after cementation; in the laser-sintered Co-Cr structure, it was, on average, 60.45 ± 8.87 µm before and 69.33 ± 9.03 µm after cementation. A highly significant difference (P<.001) was found in marginal gap measurements of galvano copings and a significant difference (P<.05) was found in marginal gap measurements of the laser-sintered Co-Cr copings. According to the SEM examination, surface properties of laser sintered Co-Cr copings showed rougher structure than galvano copings. The galvano copings showed a very smooth surface.

CONCLUSION

Marginal gaps values of both groups before and after cementation were within the clinically acceptable level. The smallest marginal gaps occurred with the use of galvano copings.     

两种树脂粘结剂对不同材料粘结性能的比较

目的：通过比较2种树脂粘结剂对不同修复材料的剪切强度来评价其粘结性能,为修复临床提供一定的依据。方法：选用两种树脂类粘结剂,将5种不同的修复材料分别粘于牙本质,测定剪切强度,并在Olympus立体显微镜下观察断裂面破坏方式。结果：用SAS的ANOVA过程对各组数据进行统计分析,结果：（1）Super-bond C＆B对各种材料均有良好的粘结强度,Panavia-F对钴铬合金最强。（2）Super-bond对各种修复材料与牙本质的粘结强度,都明显高于Panavia-F。（3）从界面破坏的光镜分析可看出,Super-bond 22.5%为粘结剂的内聚破坏,65%为混合破坏,而Panavia-F 75%为沿牙本质面断裂的粘结破坏。结论：Super-bond的粘结性能高于Panavia-F,Panavia-F对钴铬合金的粘结强度最高。     

A comparison of endodontic treatment results at two dental schools

Endodontic treatment results were assessed in a controlled clinical study in Arhus. Undergraduate students used either Kloroperka or AH26 as sealer in a randomized fashion. The findings were compared with the results from a previous study of identical design in Oslo, which involved Kloroperka, AH26 and ProcoSol. While Kloroperka performed slightly, but significantly less well than AH26 or ProcoSol in the Oslo study, no difference was found between Kloroperka and AH26 in the present study. The overall treatment results were poorer in Arhus than in Oslo, but this might be explained by a marked difference in the preoperative diagnoses and in the technical problems associated with the teeth selected for treatment. When results of endodontic treatment carried out at different locations are compared, variations in case selection and preoperative diagnoses must be corrected for in order to obtain an adequate basis for comparison.