上颌磨牙近中颊根第二根管的定位

目的　通过对 77颗离体牙根管数目的检查 ,对近中颊根第二根管口 (MB2 )与近中颊根管口(MB)腭侧根管口 (P)的相对位置分布的规律进行观察分析 ,为临床治疗提供依据。方法　选择 77颗上颌离体牙 ,其中上颌第一磨牙 35颗 ,上颌第二磨牙 4 2颗 ,截冠后寻找近中颊根及其第二根管 ,并取得上颌恒磨牙根管口间距及根管口连线夹角等数据。结果　上颌第一、二恒磨牙近中颊根存在第二根管的有 36颗 ,占总数的 4 6 .75 % ,其中有1 5颗牙近中颊第二根管钙化不通 ,2 3颗牙近中颊根的第二根管口位于腭侧与近中颊第一根管口连线的近中处 ,近中颊根管口至近中颊第二根管口的距离为 1 .2 8± 0 .35 mm ,腭侧根管口至近中颊根管口的距离为 2 .98± 0 .4 7mm ,近中颊第二根管口至 P- MB线的垂直距离为 0 .6 3± 0 .1 2 mm,P- MB线与 MB- MB2 线的夹角为 2 5 .1 4°± 8.0 3°。结论　在上颌恒磨牙根管治疗时应注意根管系统的变异 ,改进开髓洞形 ,掌握查找近中颊根第二根管方法 ,以免遗漏根管     

Surgical Treatment of Aortic Root Aneurysm Related to Marfan Syndrome in Early Childhood

The prognosis of Marfan syndrome in both adult and pediatric patients is primarily related to the cardiovascular complications. In infantile Marfan syndrome, although involvement of the mitral valve is the most frequently encountered cardiovascular lesion, the aortic root can be more worrisome because of its excessive dilatation, leading to aortic insufficiency or dissection. If the role of elective surgery is relatively well defined for adult patients, it is still debated during childhood. We report two patients, aged 22 months and 5 years, each presenting an aortic root aneurysm related to Marfan syndrome, and each treated with the Bentall procedure without specific age-related mortality or morbidity. These two patients experienced normal growth and were free of any complication for a follow-up period of 8 and 2 years, respectively. More than an absolute value of the aortic root dimension, it is the conjunction of the rate of progression of the aortic root dilatation, the degree and the duration of the aortic valve regurgitation, and its resulting left ventricular dysfunction that must be taken into consideration in choosing the surgical option.     

Exostoses of the external auditory canal: a long‐term follow‐up study of surgical treatment

To determine the postoperative incidence, extent and recurrence rate of exostoses of the external auditory canal in a cohort of patients involved in different water sports. A cross‐sectional study of 31 patients (46 ears), with exostoses treated by surgery in the Royal Cornwall Hospital between 1980 and 1999. A questionnaire was used to obtain information about the type of water exposure pre‐ and postoperatively. The extent of recurrent stenosis was assessed. The mean postoperative time interval was 10 years (sd = 4.5 years). The degree of stenosis was assessed as: minimal (<30%) in 42.6%, moderate (30–60%) in 31% and severe (>60%) in 25% of ears. The Cox regression model was used to identify factors associated with a reduction in the recurrence rate of stenosis. The use of ear plugs was highly significant (P = 0.015), as was the age of the patient at the time of operation (P = 0.004), i.e. the older the patient, the faster recurrent disease developed. There was no evidence to show that either the type or seasonal pattern of water sport activity influenced recurrence of the disease postoperatively, although preoperatively, the stenosis was more marked in association with surfing and sailing. Exostoses developed faster preoperatively in those who were in the water all year round rather than just the summer months. Of five patients who stopped water sport activity completely after surgery, four of them developed significant recurrent exostoses (>50% stenosis).     

Risk management and system failure analysis in mental health investigations

This editorial explores the way in which mental health investigations are developing in England and in particular those involving a homicide. A move away from traditional panel inquiries and towards investigations using root cause analysis (RCA) is aimed at shifting the focus from individual blame to identifying system failure. Thus it is envisaged by policy makers that the RCA approach will offer greater learning opportunities for mental health services. The key difficulties associated with panel inquiries are highlighted before describing the intended benefits of the RCA approach. Finally, five key areas where systematic research can support the development of this approach are suggested.     

正畸治疗中上颌中切牙牙根吸收的可疑相关因素分析

目的：通过分析正畸治疗引起的上颌中切牙牙根吸收的可疑相关因素，探讨各因素对牙根吸收影响的程度和大小，以期寻找有效的预测和评估因子。方法：随机选择病例资料完整的64例矫治已经结束的病例为研究对象，采用t检验、相关分析和多元逐步回归方法分析正畸治疗引起的上颌中切牙牙根吸收的可疑相关因素。结果：上颌中切牙牙根吸收的平均值为0．93mm。t检验结果显示上颌中切牙牙根吸收的大小与性别、拔牙与否和安氏分类的类型无关，相关分析结果为上颌中切牙牙根吸收的大小与疗程、方丝弓戴用的时间、根尖垂直向位移显著相关，多元逐步回归分析结果提示各相关因子的预测和评估的效率较低。结论：正畸治疗引起的上颌中切牙牙根吸收数量较小，目前尚无有效的预测和评估因子。     

试管地黄形成过程中形态发生的研究

目的 :研究试管地黄形成的形态发生过程 ,比较试管地黄与自然条件下生长的地黄在形态解剖上的异同。方法 :取离体条件下和自然条件下不同阶段形成的地黄块根 ,染色后制成石蜡切片 ,于显微镜下观察。结果与结论 :试管地黄在形态解剖方面与自然条件下生长的地黄具有一致性 ,说明试管地黄在诱导过程中未发生结构上的变化。     

根管治疗药物及其材料的细胞毒性研究进展

根管治疗中使用的消毒药物和根充材料对人体的安全性历来受到人们的关注。细胞毒性是评价其安全性的重要指标之一。下面就近年来有关常用根管冲洗剂、根管消毒药物、根管充填材料、根尖倒充填材料和髓腔穿孔修复材料的细胞毒性的研究进展作一综述。     

Vitapex与根管糊剂治疗慢性根尖周炎的效果比较

目的比较Vitapex与根管糊剂治疗慢性根尖周炎的临床效果。方法将360例患者(398颗患牙)随机分成A、B两组,A组(204颗患牙)用Vitapex加牙胶尖行根管充填,B组(194颗患牙)用传统根管糊剂加牙胶尖充填,随访1年后评定其临床疗效。结果A组治愈162颗,好转24颗,总有效率为91.18%。B组治愈116颗,好转22颗,总有效率71.13%,两组比较差异有统计学意义(χ2=26.39,P<0.05)。结论Vitapex在根管治疗中的效果明显优于传统根管糊剂,值得推广应用。     

根管锥度和循环疲劳对牙根力学性能的影响

目的：分析根管预备锥度和循环疲劳对离体牙根力学性能的影响。方法：将32颗离体下颌第一前磨牙随机分成4组,每组8颗牙齿,截冠后将每组的牙根分别预备成0.02、0.04、0.06、0.08锥度,使用侧方加压充填根管。随后每组中随机抽取4颗牙根做循环疲劳实验,疲劳前后均做扫描电镜观察牙根表面形态,最后对所有牙根进行抗压强度测试。结果：各锥度组随锥度的增大牙根抗压强度值有降低趋势,但无统计学差异（P〉0.05）;疲劳实验后0.08锥度牙根表面裂纹明显多于疲劳前,疲劳实验中实验组和对照组两组离体牙根抗压强度值无统计学差异（P〉0.05）;且疲劳和锥度两因素之间没有交互作用（P〉0.05）。结论：根管预备后锥度在0.08以内对牙根的整体抗压性能和抗疲劳性能无明显影响。