软磁合金与4 种齿科合金间电偶腐蚀的浸泡实验研究

目的:评价铁铬钼软磁合金与4种口腔常用合金在模拟口腔环境中的电偶腐蚀性能。方法:Fe-16Cr-2Mo软磁合金分别与钛75合金、TA2型纯钛、Co-Cr合金、Ni-Cr烤瓷合金组成的4组电偶对在人工唾液中浸泡6个月后,以原子吸收光谱仪测定每组电偶对浸泡液中溶出的金属离子浓度。结果:4组电偶对中析出的离子量与对照组相比均无显著差异(P>0.05)。结论:铁铬钼软磁合金在口腔环境中与牙科常用合金间可以认为不会有电偶腐蚀发生。     

氮化钛纳米膜提高磁性附着体铁铬钼合金防腐蚀性的研究

目的 应用离子束辅助沉积技术制备氮化钛纳米膜提高磁性附着体铁铬钼软磁合金在口腔环境中的防腐蚀性。方法 应用电子拉伸机对镀膜后软磁合金进行磁力检测。采用电化学腐蚀法模拟在口腔环境下对镀膜前后的铁铬钼合金自腐蚀电位、初始稳态电位、维钝电流密度、腐蚀电流密度、极化电阻进行测定。结果 镀膜后软磁合金磁力无明显改变，镀膜前后磁力值差异无显著性。经表面镀膜处理的铁铬钼软磁合金的自腐蚀电位、极化电阻明显高于未经表面处理的合金者，腐蚀电流密度、初始稳态电位、维钝电流密度明显低于未经表面处理的合金者。统计学处理表明差异有显著性。结论 经氮化钛纳米膜处理的铁铬钼软磁合金在口腔环境中的防腐蚀性，较未经表面镀膜处理的铁铬钼合金明显提高。     

TiN纳米薄膜提高磁性附着体Fe-Cr-Mo合金显微硬度的研究

目的 :研究应用离子束辅助沉积技术 (ionbeamassisteddeposition ,IBAD)制备TiN纳米薄膜提高铁铬钼软磁合金在口腔环境中的耐磨损性能。方法 :测量在模拟口腔环境中 ,电化学腐蚀前后 ,未镀膜及三种不同条件镀TiN纳米薄膜的铁铬钼合金显微硬度值。结果 :无论腐蚀前后 ,镀TiN纳米薄膜均较未镀膜的合金显微硬度值明显提高。统计学分析具有显著性差异 (P <0 .0 1)。其中 ,离子束溅射 4h、厚为 2 μm的镀膜提高最多。 结论 :TiN纳米薄膜显著提高铁铬钼合金的显微硬度值 ,从而提高其耐磨损性能。     

Ti-6Al-7Nb合金与口腔常用合金间电偶腐蚀的研究

目的:评价Ti-6Al-7Nb合金与3种口腔常用合金在人工唾液中的电偶腐蚀性.方法:运用电化学方法测量Ti-6Al-7Nb合金与纯钛(TA2型)、Ni-Cr烤瓷合金、Co-Cr合金4种金属材料在人工唾液中的自腐蚀电位(Ecorr)塔菲尔曲线,并测量Ti-6Al-7Nb合金与其他3种金属组成电偶对后的电偶电流密度值,分析Ti-6Al-7Nb合金与不同金属偶合后的耐电偶腐蚀能力.结果:Ti-6Al-7Nb合金、TA2、Co-Cr合金和Ni-Cr烤瓷合金的Ecorr值(mV)分别为-111.8±0.02、-156.6±0.03、-246.2±-0.07和-298±0.08,两两比较均有显著性差异(P＜0.01);Ti-6Al-7Nb合金与TA2、Co-Cr合金和Ni-Cr烤瓷合金组成电偶对后测得的电偶电流密度值(μA/cm2)分别为0.46±0.21、1.37±0.90和2.25±1.52,两两比较均有显著性差异(P＜0.01).结论:Ti-6Al-7Nb合金在人工唾液环境中具有良好的耐腐蚀性能,与牙科常用合金偶合后不会有电偶腐蚀发生.     

激光焊接铁铬钼合金与钴铬合金的机械性能

目的：测试激光焊接铁铬钼软磁合金与钴铬合金的机械性能，为临床应用提供参考。方法：采用国产Nd：YANG程控激光焊接机焊接铁铬钼软磁合金与钴铬合金，以激光焊接钴铬合金作为对照。利用Instron万能拉仲实验机测试焊接后的拉仲强度、0．2％屈服强度，作断裂口的扫描电镜分析，并分别进行比较。结果：激光焊接铁铬钼软磁合金与钴铬合金的拉伸强度、0．2％屈服强度与对照组无差别。激光焊接铁铬钼合金与钴铬合金的断裂口呈韧性—解理混合型断裂，而激光焊接钴铬合金的断口呈准解理断裂。结论：激光焊接铁铬钼软磁合金与钴铬合金的机械性能可满足临床需要。     

常用牙科合金与铁铬钼软磁合金激光焊接件的拉伸性能评价

目的:评价激光焊接常用牙科合金与铁铬钼软磁合金后的拉伸性能.方法:铸造钴铬合金、镍铬合金拉伸试件,随机分组并分别与铁铬钳软磁合金试件用激光焊接机焊接,以激光焊接同种钻铬合金拉伸试件为对照组.利用万能拉伸试验机测试焊接后试件的抗拉强度、0.2%屈服强度,利用扫描电镜分析断裂口,并分别进行比较.结果:激光焊接铁铬钼软磁合金与钴铬合金、镍铬合金的扰拉强度、0.2%屈服强度与激光焊接同种钴铬合金无统计学差别.激光焊接铁铬钼合金与镍铬合金的断裂口呈韧件断裂,激光焊接铁铬钼合金与钴铬合金的断裂口呈韧性-解理混合型断裂,而激光焊接钻铬合金的断口呈准解理断裂.结论:从拉伸性能方面考虑,激光焊接铁铬铜软磁合金与钴铬合金、镍铬合金可应用于磁性固位体构件的焊接.     

钛种植体与冠修复金属电偶腐蚀电流的研究

目的 通过对HBIC型钛种植体与口腔科常用修复烤瓷合金在中性和酸性人工唾液中的电偶腐蚀的综合评价,筛选更适合种植体上部结构的冠修复材料.方法 选择HBIC型钛种植体(T-H)以及镍铬合金(Ni)、钴铬合金(Co)、金铂合金(Au)、铸造纯钛(Ti),每种金属制成直径4mm、高10mm的圆柱体电极各40个.采用电化学方法,在自行配制的pH =6.8、pH =5.6两种人工唾液中检测4种合金分别与T-H组成的电偶对的电偶电流密度(Id),并绘制出各自的电流时间曲线.结果 在中性人工唾液中四种电流密度依次为IdNi＞ IdCo＞IdTi＞IdAu,其中Ni组与Au组、Ti组间有统计学差异(P＜0.05),Co组与Ni组、Ti组、Au组,Ti组与Au组间无统计学差异(P＞0.05).在酸性人工唾液中四种电流密度依次为IdNi＞IdCo＞IdAu＞IdTi,其中Ni组显著大于Ti组、Co组、Au组,有统计学差异(P＜0.05),Ti组、Co组、Au组三组间无统计学差异(P＞0.05).扫描电镜观察,酸性环境中镍铬合金发生少量坑状腐蚀形貌,其余合金与中性环境相比无明显变化.结论 两种唾液中镍铬合金组电偶电流较大.酸性环境能增大电偶腐蚀,对镍铬合金影响较大,镍铬合金不适宜作为钛种植体上部冠修复材料.     

Ti-6Al-7Nb合金铸造后抗腐蚀性能的研究

目的：研究Ti-6Al-7Nd合金在模拟口腔环境中的电化学腐蚀行为，及铸模温度对合金抗腐蚀能力的影响。方法：制作Ti-6Al-7Nd、Ti-6Al-4V、TA2三种金属铸造试件共18个，每种金属在铸模温度为室温和300℃时各铸造一组，每组试件3个。采用阳极极化技术，在37℃人工唾液中测定其稳态电位（Ecorr)，并记录其动电位极化同线。结果：在同样的铸模温度下，两种合金的Ecorr电位相近，TA2则明显负移；三种金属的Ep值相近。随着铸模温度升高，三种材料的致钝电流密度和维钝电流密度均增大，Ep正移。但其中Ti-6Al-7Nd合金的两个电流密度小于对照组。结论：Ti-6Al-7Nd合金易于钝化，其抗电化学腐蚀能力高于纯钛，与Ti-6Al-4V合金相似。铸造温度升高会降低钛材抗腐蚀能力。     

牙用镍铬合金表面不同涂层电化学腐蚀研究

目的:通过电化学腐蚀法测试镍铬合金表面不同涂层在中性及酸性环境中的抗腐蚀性能.方法:分别以中性和酸性人工唾液为电解液,测量不同涂层的镍铬合金试件电极的自然腐蚀电位Ecorr、极化电阻Rp.结果:在中性和酸性人工唾液中,无论镀膜与否的镍铬合金的自腐蚀电位(Ecorr)均为正值,不易发生电化学腐蚀和电偶腐蚀.结论:氮化钛膜、电镀金膜、金泥涂层及金瓷涂层的镍铬合金具有较强抗腐蚀性和美观性,可提高基体金属的耐腐蚀性能.     

口腔修复常用合金稳态电位的测定

目的 评价口腔修复常用合金的稳态电位及其发生腐蚀的倾向。方法 测量五种修复常用合金在人工唾液中的初浸电位及24h后的稳态电位，并作统计学分析。结果 得出五种材料的电偶序为：金合金、纯钛、钴铬合金、无锌银汞、含锌银汞。浸泡24h前后，金合金、纯钛、钴铬合金均为正移，而无锌银汞则负向移动。无锌银汞和含锌银汞的电位有显著性差异（P〈0．05）。结论 金合金、纯钛、钴铬合金是耐腐蚀性较好的材料。无法避免不同金属的同时应用时，应尽量选择电偶序中相邻的两种金属。建议临床使用无锌银汞代替含锌银汞。     

Evidence of the validity of a model of determinants of quality of restorative dental care

A model describing the relationship between self-reported quality of restorative dentistry and dentist characteristics for 119 Montana general dentists is presented. The best predictors formed a significant model explaining 22% of the variance of the quality measure. Results are contrasted with a previous estimation of the model for 102 Washington general practitioners. Evidence for the external validity of the model is presented.     

Experimental evidence of formation of imines in the course of reduction of hydrazones

The reduction of hydrazones is generally suggested to proceed through a reductive cleavage of the nitrogen–nitrogen bond followed by a reduction of the carbon–nitrogen bond. This sequence of reduction processes is here supported for fluorenone (V) and benzophenone (VI) hydrazones as well as by a comparison of the reduction of fluorenone and benzophenone hydrazonium ions (I,III) with corresponding imines (II,IV). Another proof of the presence of imines as intermediates is the splitting of four-electron waves of hydrazones V and VI and hydrazonium ions I and VIII into two waves at pH < 2. This has been interpreted as due to differences in slopes dE_1/2/dpH and pK_a-values of protonated hydrazine derivatives on one side and corresponding imines on the other. In this pH-range imines formed in reductions of VI and VIII are reduced in a single two-electron wave, those of I and V in two one-electron steps. Fluorenone imine (II) is sufficiently stable to allow recording of time-independent current–voltage curves between pH 6 and 11. In this pH-range the imine (II) is reduced in two one-electron steps. Benzophenone imine (IV) has been found stable between pH 4.6 and 12. At pH 4.6–8 the reduction of the imine IV takes place in a single two-electron step, at pH 8–12 in two one-electron steps. Final proof of the initial cleavage of the N–N bond is presented by comparison with the reduction of nitrones.     

不同剂型玻璃离子水门汀溶解性比较研究

目的:研究、比较不同剂型玻璃离子水门汀的溶解性和表面微观形态改变,为临床使用提供依据.方法:将3M树脂加强型玻璃离子水门汀(水粉剂型)、GC玻璃离子水门汀(水粉剂型)及GC玻璃离子水门汀(双糊剂型)分别在人工唾液中浸泡30 d,冷热循环15000次,烘干测重,比较前后质量变化,计算溶解率,并用扫描电镜观察表面微观改变.结果:不同剂型的玻璃离子水门汀溶解率由高到低分别为3M树脂加强型玻璃离子水门汀(水粉剂型)、GC玻璃离子水门汀(水粉剂型)、GC玻璃离子水门汀(双糊剂型).3种玻璃离子水门汀经浸泡溶解后,SEM扫描表面微观形态可观察到GE玻璃离子水门汀(双糊剂型)表面形态改变较少,其他2组玻璃离子水门汀表面微观改变较多.结论:双糊剂型玻璃离子水门汀理化性能及溶解率均低于传统水粉剂型,是未来临床修复治疗的的良好选择.     

Design of clinical trials of traditional therapies of periodontitis

The present paper on the design of clinical trials of periodontal therapy first addresses the issue of the etiology of periodontal disease. It is suggested that most if not all forms of destructive periodontal disease are caused by microorganisms and that there are different forms of disease with different microbial etiologies. The progressive nature of destructive periodontal disease is subsequently discussed and it is emphasized that, in a given patient, periodontal sites which show signs of inflammation and attachment loss may not over a period of several months and years show further sign of attachment loss. The present methods of assessing periodontal disease do not allow us to discriminate between potentially active and inactive sites in untreated patients. The significance and variability of indicators of periodontal disease such as bleeding on probing, probing pocket depth and probing attachment level measurements are discussed. The errors inherent in the various measurements are analyzed and suggestions are presented describing how alterations in any of the above parameters could be identified and presented in a clinical trial. Of concern for the statistical analysis of clinical data of periodontal disease is the definition of the "experimental unit". For a number of years, the "experimental unit" in periodontal trials was the patient. It is clear, however, that different sites within the same individual show different patterns of disease progression and lesion morphology and often respond differently to periodontal therapy. Statistical analyses must consequently be designed which recognize differences in site-to-site infection and lesion morphology within a common host. Until such analyses are available, the investigator should be wary of pooling data within the same individual, since such pooling may obscure meaningful alternatives which may take place in individual periodontal sites. Some goals of periodontal therapy are subsequently identified. 4 goals are discussed more in detail, namely: to establish conditions which will allow the patient to maintain a dentition without further breakdown of the periodontium; to reduce pocket depth to establish an anatomy in the dentogingival region which with proper maintainance care will prevent the re-establishment of the subgingival infection; to gain attachment as a result of treatment; to assess the effect of a certain chemotherapeutic agent on periodontal disease.     

Evaluation of efficacy of chemiluminescence for diagnosis of leukoplakia

ObjectiveLeukoplakia is the most common potentially malignant disorder preceding oral cancer. Chemiluminescence has been developed as an adjunct to conventional examination for the diagnosis of these potentially malignant disorders. This study was conducted to assess the efficacy of chemiluminescence in the diagnosis of leukoplakia and to compare the results with histopathological examination.Study designA total of 50 patients with leukoplakia were included from the outpatients attending the Department of Oral Medicine and Radiology, Dental Hospital, Bengaluru, Karnataka, India. These patients were subjected to conventional oral examination followed by chemiluminescent examination with Vizilite (Zila, Fort Collins, CO, USA) and biopsy for histopathological confirmation.ResultsThe sensitivity, specificity, positive predictive value, and negative predictive value of chemiluminescence were 93.75%, 55.56%, 78.95%, and 83.3%, respectively. The overall accuracy of chemiluminescence was 80%. A statistically significant association was observed between histopathology results and chemiluminescence results.ConclusionAlthough it is an easy, safe, minimal time consuming, and noninvasive technique, it has only adjunctive utility and it does not replace biopsy for the diagnosis of leukoplakia.     

颌骨动静脉畸形的栓塞治疗

目的：总结直接穿刺结合经血管内介入栓塞治疗颌骨动静脉静脉畸形的经验。方法：收治凳骨动静脉畸形患者6例,均进行了介入栓塞治疗。采用的栓塞材料为附凝血棉纤毛的螺圈,聚乙烯醇泡沫微粒和二氰基丙烯酸对丁酯。数字减影颈动脉造影在PHILIPSV300下完成。结果6例颌骨动静脉畸形患者中4,例急性出血得到了快速、有效控制,1例慢性渗血的右下 骨动静脉畸形患者,介入栓塞治疗,拔除松动的右下凳第一磨牙,有效地控制了出血,另1例伴局部软组织搏动性膨隆的上凳骨动静脉畸形患者,介入治疗后膨隆的搏动性得到明显改善,栓塞治疗后分别随访3－24个月,均未发现有口腔内渗血或出血。随访的X线片上,病灶区可见新骨形成。结论：局部穿刺结合经血管内介入栓塞治疗颌骨动静畸形是一种安全、有效的治疗方法。     

正畸患者切牙影像失真发生情况分析

目的研究正畸患者曲面体层片上的切牙影像失真发生情况，并分析其原因。 方法从中山大学附属口腔医院放射科影像数据库中选取500例正畸患者的曲面体层片和头影测量侧位片，所有曲面体层片均采用咬合杆投照，分别从切牙牙体影像放大、缩小、牙根变短、根尖模糊等评价指标分析上下颌切牙影像失真的发生情况，在头影测量侧位片上测量中切牙根尖-对颌切牙切缘的距离，探讨切牙影像失真发生的原因。采用SPSS 19.0统计软件对所得数据进行统计学检验。 结果500例患者中，切牙牙体影像正常者共417例，切牙牙体影像失真者共83例，影像失真发生率16.6%，其中切牙牙体影像放大17例、牙体影像缩小0例、牙根变短30例，牙根影像变短伴模糊36例。影像失真患者的根尖-切缘距离大于影像正常的患者，差异有统计学意义（F = 5 187.18，P = 0）；影像失真患者的覆盖值大于影像正常的患者，差异有统计学意义（F>477，P = 0）。 结论严重牙颌面畸形如反 、深覆盖是导致曲面体层片的切牙影像失真的主要原因之一。     

正常青年Monson球面半径的测量研究

目的测量正常青年Monson球面半径。方法选择60名(男30名,女30名)正常青年制取全口印模,应用立体摄影成像的原理与方法对Monson球面半径进行测量和统计学处理。结果Monson球面的半径平均为10.173 cm,大于理论值10.160 cm,差异有显著性(P<0.01);男、女性球面半径差异无显著性。结论本实验所得到的数据可作为全口义齿修复中记录颌位关系的一个参量。     

鼻测量法的进展

唇裂术后继发畸形是指唇裂修复术后,仍遗留或继发于手术操作和生长发育变化而表现出来的一类畸形[1]。包括唇畸形、鼻畸形和颌骨畸形。其修复较原发性唇裂修复更复杂,更灵活多变。而导致其修复复杂性的一个重要原因即是局部组织结构复杂变异和缺乏可靠的三维测量手段[2],鼻畸形     

《口腔医学》杂志2007年度有关信息的分析

目的通过对《口腔医学》2007年全年文献的回顾和分析,了解我国口腔临床医学的研究现状。方法阅读2007年《口腔医学》全年的文献,对各种信息进行了分类汇总,根据设计类型对临床一次性文献进行了分类,并对其中的试验性研究文章进行质量分析。结果《口腔医学》2007年全年的一次性文献274篇,基础和临床文献分别为108和166篇,以临床文献为主(60.58%)。在临床研究文献中,属于观察性、分析性和试验性的文献分别为97、9和60篇,观察性文献所占比例为36.14%,高于以往的报道。60篇观察性文献中,全都设有对照;统计方法应用得当者44篇;真正做到随机、盲法的分别只有4和2篇。结论我国口腔临床方面的研究水平近年来提高明显,但设计的科学性方面有待提高。