附子水煎剂对家兔离体肺动脉血管的舒张作用

目的:研究附子Monkshood Root(DMR)水煎剂对肺动脉环的舒张作用及机制.方法:采用家兔离体肺动脉平滑肌标本,以去甲肾上腺素(NA)预收缩肺动脉后,给予不同剂量的附子观察其张力变化,并探讨去除血管内皮、给予NO合酶抑制剂左旋硝基精氨酸(L-NNA)、甲烯蓝(MB)、环氧酶抑制剂吲哚美辛和β肾上腺素能受体阻断剂普萘洛尔对血管张力变化的影响.结果:附子对血管环静息张力无明显影响,但不同剂量的附子可使10-6mol·L-1NA预收缩血管产生明显舒张(r=0.71,P＜0.001).去除血管内皮、10-4mol·L-1L-NNA或10-5mol·L-1MB可减弱附子的舒张作用.另外,1 mg·mL-1DMR对无内皮血管环NA和KCl的量效曲线无明显影响,DMB温育前后NA的PD2值为7.56±0.95和7.30±0.83,P＞0.05;KCl的PD2值为1.74±0.48和1.71±0.51,P＞0.05.结论:附子水煎剂对肺动脉的舒张作用是内皮依赖性,与内皮细胞释放的NO有关,而与平滑肌细胞膜上的受体依赖性Ca2 通道和电压依赖性Ca2 无关.     

镍钛减速机用于根管预备的临床研究

目的　探讨镍钛减速机用于根管预备的临床效果。方法　在门诊患者中选择年龄为 2 0～ 5 0岁需做根管治疗的病人 2 0 0例 ,共计 2 0 0颗患牙 ,随机分成实验和对照两组 ,两组分别采用旋转镍钛根管扩大系统及用不锈钢 K型和 H型手动扩挫系统扩挫根管的方法进行根管预备 ,记录根管预备所需时间及术后疼痛反应的发生情况 ,并进行比较。结果　实验及对照两组中前牙根管预备所需的时间平均为 (4.92± 0 .73) min和 (5 .0 16±0 .0 2 5 ) m in,磨牙根管预备所需的时间平均为 (14 .4± 2 .8) min和 (17.8± 2 .2 ) m in;两组比较 ,有关前牙的根管预备所需时间比较差异无统计学意义 (t=1.33,P>0 .0 5 ) ;而磨牙的根管预备所需时间比较差异有统计学意义 (t=8.113,P<0 .0 5 ) ,实验组短于对照组。术后疼痛反应发生率两组比较 ,实验组 (12 % )明显低于对照组 (2 9% ) (χ2 =88,P<0 .0 1)。结论　镍钛减速机用于根管预备 ,大大提高了工作效率 ,减少了患者术后疼痛反应的发生 ,因此 ,镍钛机扩技术在临床上值得推广应用。     

根龋的根面易感性分析

目的:分析根面龋与根面易感性的关系。方法:采用分层随机抽样方法,对唐山市600名40岁以上中老年人进行口腔健康检查,数据应用SAS8.0软件进行单因素分析。结果:根面龋易感性高的根面为前牙、下颌前磨牙、磨牙的唇(颊)面、下前牙与上颌磨牙的舌面、前磨牙的远中面、磨牙的近中面。结论:根面是根龋的易感因素。     

根管治疗是否恰填疗效对比

目的研究在根管治疗中根充长度对疗效的影响。方法对200颗根充治疗后2年的牙齿进行拍片检查,根据根充长度是否恰填分组:恰填134颗,非恰填(欠填或超填)66颗,应用根尖周指数并综合临床检查,对其疗效进行评价。结果根管治疗成功率为68.8%;恰填根管的成功率(80.4%)比非恰填的成功率(45.8%)明显提高(P<0.01)。治疗后未行冠修复者易出现冠劈裂,不能保留而拔除者4颗,占4%。结论在进行根管治疗时,根充长度是否恰填明显影响治疗效果。     

不同根管器械用于预备弯曲根管的效果比较

目的比较机用镍钛K锉、手用镍钛K锉、手用不锈钢K锉,在预备弯曲根管时的切削能力和成形能力。方法将30个树脂块弯曲人工根管分为三组,每组10个,分别用镍钛机用K锉、手用镍钛K锉、手用不锈钢K锉预备根管,用光学显微镜观察根管的偏移情况及标本的失重量进行对比分析。结果镍钛机用K锉无根管偏移,手用不锈钢K锉可发生根管偏移。预备后的根尖孔直径镍钛K锉组明显小于不锈钢K锉组(P<001)。结论镍钛器械保持原根管解剖走向的能力优于手用不锈钢K锉。镍钛机用K锉能保持弯曲根管良好的根管形态,建议临床广泛应用。     

火把花根片在小鼠骨髓移植模型中减轻急性移植物抗宿主病的实验研究

目的探讨火把花根片在小鼠骨髓移植模型中减轻急性移植物抗宿主病(acute graft-versus-host disease,aGVHD)的效果及可能的作用机制。方法建立小鼠异基因骨髓移植GVHD模型,预处理为放疗8．0Gy,分为：对照组(n=10)异基因骨髓细胞(2×10~6)加脾T淋巴细胞(2×10~6)移植组；火把花根片组(n=20)异基因骨髓细胞(2×10~6)加脾T淋巴细胞(2×10~6)移植加火把花根片预防组。比较受鼠生存时间和GVHD发生情况,受鼠外周血象中白细胞、血球压积等恢复情况和骨髓细胞中嵌合体H-2D~b阳性细胞百分比以评价造血重建。在移植后不同时间点分别采用流式细胞仪检测受鼠的脾细胞中CD4~+和CD8~+以及CD25和CD69的表达。结果移植后对照组受鼠均于25天内死于GVHD,火把花根片组GVHD的发生率为20%(4/20),与对照组小鼠相比,存活率和时间明显增高和延长(P＜0．01)；存活的火把花根片组小鼠(n=4)40天时骨髓细胞中的H-2D~b阳性细胞百分比达(93．38±4．32)%。移植后10天开始,火把花根片组小鼠CD4~+和CD8~+T细胞比例明显低于对照组(P＜0．...     

无托槽隐形矫治整体移动的研究进展

无托槽隐形矫治凭借美观、舒适等优点，受到众多医生和患者的青睐。因矫治力加载的特殊性，其临床适应症较窄，如何实现牙齿整体移动成为拓宽适应症的重要一环。但目前关于整体移动的研究缺乏系统整理，本文将对整体移动生物力学基础、控根附件种类、控根附件优化措施的相关研究进行归纳，以期为临床上无托槽隐形矫治提供参考。     

根面龋的预防与治疗

随着我国人口老龄化加剧,根面龋的发生率逐年升高。与冠部龋坏不同,根面龋多发生于老年患者牙龈退缩后暴露的根面上,主要累及根部牙骨质和牙本质,在发病特点、临床表征、诊断和防治上都有其特异性。本文从根面龋的病因和危险因素、病理和临床表现、分类、三级预防等方面进行阐述,以期为根面龋的临床防治提供参考。     

Endodontic retreatment of a lower canine associated with a periapical lesion: case report of an unusual anatomy

ObjectivesTo describe the endodontic orthograde retreatment of a lower canine with a rare anatomy, affected by a symptomatic periapical lesion.Materials and methodsA 30-year-old Caucasian woman came to our office reporting severe pain and swelling located at the right mandible. A two-roots/two-canals configuration was discovered for the lower canine which sustained the periapical infection; a missed lingual canal was not recognized and treated at the previous primary endodontic therapy.A full pre-operative examination and diagnosis, the application of modern endodontic strategies along with the use of magnification technologies (like the Surgical Operating Microscope - SOM) and proper disinfection protocols were employed for endodontic re-treatment.Result and conclusionsHealing of the periapical infection was clinically and radiographically confirmed at a 9-month follow-up. Endodontists should know the anatomical variations of human teeth and be vigilant about them when approaching treatments. More than a single radiographic projection is recommended in the diagnostic phase.Careful procedures related to instrumentation, cleaning and filling of the entire root canal system enhance the potential for healing of apical lesions.     

La risoluzione delle complessità nei ritrattamenti

ObjectivesThe aim of this study is to describe the main causes and prevalence of endodontic therapy failures, to promote a diagnostic and prognostic work-up suited to the relevant pathology evolution degree and to suggest appropriate clinical strategies to achieve the expected results.Materials and methodsThrough an extensive review of recent literature, combined with an accurate analysis of clinical cases and epidemiological investigation, it was possible to gather and evaluate the necessary information and data for providing clinical dictates on the solution of endodontic retreatment problems.ResultsThe success percentage of endodontic retreatments is quite variable, ranging from 60% to 85% of treated cases. Such percentage is strongly dependent on two critical variables: the preoperative condition of periapical tissues and the previously provided treatment. A chronic apical periodontitis subjected to inadequate therapy leading to the structural alteration of dental elements, is indeed a crucial factor affecting the retreatment prognosis.ConclusionsAll retreatment procedures should be preceded by an accurate case analysis. Adverse anatomical conditions and periapical bone lesions may predict an unfavorable prognosis and should be taken into great consideration. However, in all other clinical conditions, high success rates can be achieved, ensuring a long-term survival of dental elements.