牙体牙髓病学实验教学中发展性评价体系的构建和应用

目的探讨牙体牙髓病学实验教学考评体系中的发展性评价方法的应用效果。方法使用发展性评价方法检测口腔医学专业学生的牙体牙髓病学实验教学效果,并与终结性评价结果进行对比,统计方法为配对t检验,检验水准α＝0.05。结果发展性评价结果与终结性评价结果差异有统计学意义（t＝2.221,P＝0.038）。结论所构建的发展性评价体系可反映学生学习状态,为教师因材施教、提高教学质量提供途径。     

PBL教学法在牙体牙髓病学研究生临床教学中的应用

医学教学领域广泛采用PBL作为一种新型的教学模式,在教学过程中收到了很好的效果。本文针对牙体牙髓病学研究生临床教学中独立性操作要求高,知识更新快等特点,探讨了运用PBL教学法进行临床教学的过程中,在提出问题、收集资料、集中讨论、临床操作和归纳总结几个环节的方法和特点。分析了PBL教学运用于牙体牙髓病学研究生临床教学的过程中,对学生,病人和教师所带来的益处,为牙体牙髓病教学以至口腔医学教学方法的改革提供一些经验。     

何来"牙体牙髓病学"?

世界在发展，万事万物在发展，文字也在发展，口腔医学各专业也在发展。但是有些名称似乎不大通顺，不大合适，例如从20世纪80年代以后，就开始出现了“牙体牙髓病学”这一新名词，原来开始于建立牙体牙髓病学学组时用了这个名词，现在却通行了。     

PBL与SP联合教学法在本科生牙体牙髓病学课间实习中的应用

目的:将PBL与SP联合教学法应用到五年制本科生牙体牙髓病学课间实习教学,以提高教学质量.方法:将中国医科大学口腔医学专业97期五年制本科104人随机分为2组,每组52人,分别采用以问题为中心教学法(problem-based learning,PBL)与标准化病人(standardized patients,SP)联合教学法、以授课为中心(lecture-based learning,LBL)传统模式授课,通过考试和问卷调查评价教学效果.所有数据采用SPSS 11.5软件包进行t检验.结果:PBL与SP联合教学组在病例分析、理论总分、实践总分、总成绩4项的分数高于传统LBL组(P＜0.05).在基础知识成绩比较方面,LBL组成绩显著高于PBL与SP联合教学组(P＜0.05).PBL与SP联合教学组的学生对于SP的表现比较满意,非常喜欢联合教学法.结论:PBL与SP联合教学法能够提高学生各方面的能力,获得满意的教学效果,值得推广实施.     

情景教学模式在牙体牙髓病学临床前期实习中的应用

目的 将情景教学模式应用在牙体牙髓病学临床前期实习中,以期提高教学质量。方法 将中国医科大学95期口腔医学专业19班32名学生随机分为2组,每组16人。分别采用情景教学模式、传统授课模式授课,通过考试和问卷调查评价教学效果。理论考试成绩采用SPSS 17. 0软件包进行t检验。结果 在基础知识、病例分析、口腔检查方面,2组学生之间的分数无显著差异（P>0.05）,实验组学生在病史采集、病历书写、实践总分、总成绩方面的分数高于对照组,差异显著（P<0.05）。实验组对情景教学模式普遍持赞成观点。结论 参与情景教学模式的学生喜欢这一新的教学方式。情景教学模式能够提高学生各方面的能力,获得满意的教学效果,适用于临床前期实习。     

微课在牙体牙髓病学住院医师规范化培训中的应用

目的:评价微课教学法用于牙体牙髓病学住院医师规范化培训的效果。方法:将20名牙体牙髓病学专业轮转住院医师随机分为2组,每组10人,分别采用微课教学法、以授课为中心（lecture-based learning,LBL）的传统教学法进行授课,通过考试和问卷调查对教学效果进行评价。采用 SPSS18.0软件包对考试成绩进行t检验。结果:微课组实践成绩、总成绩显著高于LBL组（P<0.05）;理论成绩微课组高于LBL组,但差异无统计学意义（P>0.05）。问卷调查显示,学生认可微课的新颖性及灵活性,有利于培养自主学习能力,促进师生间的交流,但微课视频的制作水平有待提高。结论:采用微课教学法取得了良好的教学效果,可以在住院医师规范化培训中推广实施。     

PBL模式在不同类型学生牙体牙髓病学临床期教学中的应用比较

目的:将PBL教学模式应用到我院牙体牙髓病科本科生、硕士研究生和进修生的临床期教学中,探寻牙体牙髓病学临床教学中针对不同层次学生的最适合的教学模式。方法:随机选取两期本科生(A组),一期硕士研究生(B组),一期进修生(C组)为研究对象。分别在各组实习期间插入PBL教学课程,通过学生问卷调查和PBL教学考核,比较各组学生对PBL教学的反应和教学效果。结果:大多数学生对PBL教学模式有积极的反应,考核成绩B组高于A组和C组。从单项成绩上分析,C组学习主动性不及A组和B组,但在临床思辩方面C组高于A组;在搜集资料、书写学习报告以及口头表达方面,B组强于A、C组;但A组在团队合作上强于B、C组。结论:采用PBL教学模式时,应针对本科生、研究生、进修生各自的特点因材施教。     

浅谈口腔七年制学员牙体牙髓病学的临床实习

口腔七年制学员的临床实习，既是从理论课学习到临床实践的重要阶段，也是迈入课题研究的必经之路。根据七年制学员牙体牙髓病学临床实习教学大纲要求，结合2001～2002年度口腔七年制学员牙体牙髓病学的临床实习教学，本文从三个方面简要介绍了本次教学的体会和经验。     

浅谈四年制本科牙体牙髓病学的教学体会

在我校第一批四年制口腔医学本科战士学员的牙体牙髓病学的教学中,我们通过掌握学员情况,因材施教;认准培养目标,按纲施教;精心实施教学,注重实效,圆满完成了教学任务,教学相长,取得良好教学效果。     

牙体牙髓病学临床研讨会通知

由中华口腔医学会牙体牙髓病学专业委员会主办、武汉大学口腔医学院承办的牙体牙髓病学临床研讨会定于2005年10月13～14日在武汉举行。     

The effect of endodontic access cavity preparation and subsequent restorative procedures on molar crown retention

Preparation of an endodontic access cavity through a full crown may affect its retention. This study was undertaken to investigate the effects on molar crown retention of endodontic access cavities and their subsequent restoration. Thirty human molars were mounted in resin, crown preparations were cut and their surface areas were determined. Vented metal copings were cemented with zinc phosphate and the forces required to displace each coping were measured using a tensile-testing machine. The copings were recemented, access cavities were cut and their surface areas determined prior to the displacement forces being re-measured. The copings were recemented, assigned to two groups, and the access cavities were restored - Group 1 with amalgam; Group 2 with glass ionomer (GIC). Displacement forces were re-measured and the copings were recemented. The occlusal margins of the access cavities were ***bevelled and restored again prior to displacement forces being re-measured. Mean displacement forces were -Group 1: Original (kg force), 37.86 ± 3.97; After access cavity, 29.28 ± 3.22; Amalgam, 50.21 ± 4.71; Amalgam + bevel, 46.45 ± 6.21. Group 2: Original, 42.77 ± 4.49; After access cavity, 39.25 ± 5.91; GIC, 48.11 ± 3.55; GIC + bevel, 39.63 ± 5.31. Statistical analyses with paired t tests showed that retentive values with access cavities were significantly lower than with intact crowns. Amalgam or GIC restorations increased retention beyond original values, significantly with amalgam. Bevelled occlusal margins decreased retention of crowns with restored access cavities but this was not significantly different from the original values. A significant relationship existed between total surface areas of the crown preparations, areas of the occlusal tables, and retentive values for crowns without access cavities. The access cavity area, as a proportion of the total area of the preparation, was related to the decrease in retention.     

铒、铬:钇钪镓石榴石激光用于牙体窝洞制备的实验研究

目的 探讨铒、铬：钇钪镓石榴石激光在牙体窝洞制备的临床应用。方法 在中国小型猪牙齿上,采用铒、铬：钇钪镓石榴石激光制备窝洞，24小时后断头处死，拔除牙齿在光镜和扫描电镜下观察牙髓反应及洞形结构。结果 经铒、铬：钇钪镓石榴石激光制备窝洞后，偶见牙髓局部充血扩张，少许浆液渗出，无牙微裂及碳化形成，窝洞内无玷污层，切割表面利于粘接固位。结论 铒、铬：钇钪镓石榴石激光在窝洞制备方面有很好的临床使用价值。     

The effect of endodontic access cavity preparation and subsequent restorative procedures on incisor crown retention

Endodontic treatment often will require access through existing crowns. This study was undertaken to determine whether endodontic access cavity preparation affected the retention of crowns in anterior teeth and then to determine whether this retention can be regained by amalgam or post-retained amalgam restorations. Twenty extracted human incisors were mounted in acrylic blocks and prepared for crowns. Metal copings were fabricated and cemented with zinc phosphate cement and the forces required to displace the copings after various procedures were measured with a tensile testing machine. Retention values for all stages were compared with the initial retentive value for each coping without an access cavity which was set at 100 per cent. Group one specimens had the following means: copings with access cavity, 85.64 ± 28.65 per cent of the initial values; amalgam flush with lingual dentine, 95.81 ± 36.2 per cent; amalgam flush with coping, 114.89 ± 34.5 per cent. Group two means were: copings with access cavity, 89.95 ± 21.42 per cent; posts and amalgam, 177.37 ± 77.5 percent. Statistical analysis with the two sample f test showed that retention with post-retained amalgam restorations showed significantly higher values when compared with access cavities without restorations (p<0.05). Retention values for post-retained restorations were significantly different from those just using amalgam. This study demonstrated that endodontic access cavities reduced the retention of the crowns, and subsequent restoration with amalgam or a post can regain the retention. Post-retained restorations showed the highest retention when compared with the amalgam restorations, but the high standard deviation in the post group indicates that the amount of retention to be gained may be clinically unpredictable.     

Histologic evaluation of three endodontic instrument/preparation techniques

Abstract 33 curved canals were prepared to quantify both the increase in canal area and predentin removal in the apical region. Compared were three different file designs/instrumentation techniques, that is “stepback” with K-flex file, “balanced force” with Flex-R file, and the Canal Master system. Following canal preparation and histological processing, cross-sections at 1 and 3 mm levels were examined using the Bioquant image analysis system. Results showed that, at the 3 mm leve, the mean increase in canal area and predentin removal showed no statistically significant difference (p> 0.05) between the techniques. At 1 mm. the step-back technique (with K-flex files) resulted in a significant increase in canal area and greater predentin removal than did the “balanced forces” (with Flex-R files) or the Canal Master system. However, although there were statistical differences, the actual differences were small; these may not translate to clinically significant differences in the 3 techniques.     

Effect of cavity preparation on the flexural strengths of acrylic resin repairs

Objective

To investigate the effect of cavity preparation on the flexural strength of heat-curing denture resin when repaired with an auto-curing resin.

Material and methods

Ninety-six rectangular specimens (64x10x2.5 mm) prepared from heat-curing denture base resin (Meliodent) were randomly divided into four groups before repair. One group was left intact as control. Each repair specimen was sectioned into two; one group was repaired using the conventional repair method (Group 1). Two groups had an additional transverse cavity (2x3.5x21.5 mm) prepared prior to the repair; one repaired with (Group 2) and one without glass-fiber reinforcement (Group 3). A three-point flexural bending test according to the ISO 1567:1999 specification⁸ for denture base polymers was carried out on all groups after 1, 7 and 30 days of water immersion. Statistical analysis was carried out using two-way ANOVA, Kruskal Wallis and post-hoc Mann Whitney tests.

Results

The highest flexural strength was observed in the control group. Control and conventional repairs group (Group 1) showed reduction in the flexural strength 30 days after water immersion. No significant change in the strength was observed for Groups 2 and 3 where the repair joints were similarly prepared with additional transverse cavity.

Conclusion

Repaired specimens showed lower flexural strength values than intact heat-curing resin. Cavity preparation had no significant effect on the flexural strength of repair with water immersion.     

Simodont虚拟仿真系统在口腔修复牙体预备教学中的应用

目的    分析Simodont虚拟仿真系统应用于全冠修复牙体预备的教学效果和特点。方法    选取第四军医大学口腔医学专业四年级学生22名,随机分为2组,每组11名,分别在传统仿真头模上（N组）和Simodont虚拟仿真系统上（S组）完成两阶段的全冠修复牙体预备操作训练,并分别进行操作考核,记录牙体预备操作时间。按照金属烤瓷全冠牙体预备的要求,分别就轴面聚合度、修复空间、点线角、肩台质量、体位姿势5个方面进行评分,并计算总分。第二次考核结束后,S组所有学生填写对Simodont虚拟仿真系统评价的调查问卷。结果    两组学生第二次考核的总分相较于第一次考核均显著提高,操作时间均明显减少,差异均有统计学意义（均P < 0.05）。在第一次考核中,两组学生总分比较,差异无统计学意义（P > 0.05）;仅在体位姿势方面,S组学生评分高于N组（P < 0.05）。在第二次考核中,S组学生总分高于N组,差异有统计学意义（P < 0.05）;在肩台质量、体位姿势方面,S组学生评分高于N组（P < 0.05）。其他方面两组学生评分比较,差异均无统计学意义（均P > 0.05）。S组学生对Simodont虚拟仿真系统评价的调查问卷结果显示,各项评分均较高,为3.6～4.9分。结论　Simodont虚拟仿真系统能够有效提高学生的全冠修复牙体预备水平,在牙体预备教学中具有潜在优势。     

The influence of the cavity preparation design on marginal accuracy of laboratory-processed resin composite restorations

The aim of this study was to evaluate the influence of different cavity preparation designs on marginal accuracy of laboratory-processed resin composite restored teeth. Eighty mandibular human third molars were selected. There were two experimental factors, occlusal isthmus width (narrow vs wide) and cuspal coverage (inlay, one-cusp onlay, two-cusp onlay, and all-cusp onlay), resulting on eight groups (N = 10). Indirect composite restorations (SR Adoro, Ivoclar-Vivadent) were manufactured and positioned over each respective preparation. Marginal accuracy evaluation was accomplished using a stereomicroscope at three points on buccal, lingual, mesial, and distal regions with 40× magnification. The results showed significant differences (P = 0.00) with wide inlay showing the best overall marginal accuracy and narrow inlay the worst one. Two-way analysis of variance (ANOVA) showed significant differences when considering the factor occlusal isthmus width (P = 0.00). In general, preparations with wide occlusal isthmus presented better results than narrow ones, except for wide all-cusp onlays; however, the test failed to show differences when considering the cuspal coverage (P = 0.42) or the interaction between both factors (P = 0.30). The effect of occlusal width extension on marginal accuracy of indirect composite resin restorations is significant, with lower values of gaps width in wide preparations, but since in a clinical situation this would mean greater removal of sound tooth structure, less-aggressive preparations combined with other restorative procedures seem to be more feasible.     

数字化评估系统在固定修复前期教学中的初步应用

目的研究数字化评估系统在固定修复前期实习中的应用，以指导教学工作。方法利hiKaVo PREPamistant数字化评估系统对学生全冠预备体的5个截面共40个指标进行评估。结果该系统可以客观反映出各学生在预备过程中的优缺点；对全班评估情况的进一步分析还可以发现学生预备过程中的整体倾向性。结论Kavo PREPassistant数字化评估系统的应用有利于教师提高前期实习的教学质量。     

不同深度牙体窝洞制备对人成牙本质细胞影响的实验研究

目的：建立牙体制洞的体外实验模型，研究不同深度的窝洞对人成牙本质细胞的影响。方法：20～30岁成人健康第三磨牙40个，随机分为4组（3个实验组和1个对照组），分别制浅（A组）、中（B组）、深（C组）3种不同深度窝洞，冠根分开，37℃，50mL／LCO2连续培养2d，每天换液。扫描电镜检测成牙本质细胞形态，显微图像分析系统计算台盼蓝染色率，并进行统计学分析。结果：髓室顶中央区域，牙本质小管开放，仅见极少量的细胞碎片，周围区域成牙本质细胞形态良好；各实验组之间的台盼蓝染色率在统计学上有显著性差异（P〈0．01）。结论：制备窝洞不同深度均对成牙本质细胞造成损伤，随着制洞深度的增加，成牙本质细胞受到的损伤明显加重。     

An evaluation of root canal preparation with the automated Excalibur endodontic handpiece

The aim of this study was to evaluate several parameters for automated root canal preparation with the Excalibur handpiece compared with hand instrumentation. The parameters investigated were straightening of curved canals, cleaning ability, working safety (loss of working length, instrument separation, perforation), cross sectional diameter before and after enlargement, and working time. Sixty curved root canals were prepared using the Excalibur handpiece and 30 curved canals with conventional hand instruments to ISO-size 35.<@head-abs-p1.l>The Excalibur left significantly less debris and smear layer on the root canal walls, but hand preparation resulted in fewer unprepared regions. Root canal curvature was well maintained by either technique; the degree of straightening depended on original root canal curvature rather than on the preparation technique. The Excalibur removed significantly more dentin. In the coronal part of the root canal, hand instruments produced significantly more round and oval cross sections; in the middle and apical part no differences could be detected. Working time was shorter for hand preparation, but the difference was not significant. Manual instrumentation proved to be safe; no instrument fracture, perforation or loss of working length could be observed, whereas automated preparation resulted in one perforation and two cases of loss of working length. Received: 7 September 1998 / Accepted: 11 March 1999