藻酸盐印模的不同保存状态对尺寸稳定性的影响

目的探讨藻酸盐印模在非密封或密封状态下放置不同时间对尺寸稳定性的影响。方法实验分为藻酸盐印模非密封10min组4、0min组和80min组,藻酸盐印模密封10min组、40min组和80min组,另设1组空白对照。分别用普通石膏、硬石膏和超硬石膏制取模型,电子数显卡尺测量标准实物及石膏模型尺寸,进行ANOVA比较(α=0.05)。结果在藻酸盐印模非密封10min、40min和80min三组中,普通石膏、硬石膏和超硬石膏所灌注的模型尺寸表现为逐渐增加的趋势;在藻酸盐印模密封10min4、0min和80min三组中,三种石膏模型尺寸变化表现为先减小后增大的趋势。各组间存在显著性差异(P<0.05)。结论随放置时间的延长,藻酸盐印模在非密封和密封不同状态下,可发生不同的印模尺寸变化。     

高温高压灭菌对加成型硅橡胶印模尺寸稳定性及细节再现性的影响

目的 探讨高温高压灭菌处理对加成型硅橡胶印模尺寸稳定性及细节再现性的影响,以期为临床应用提供参考.方法 采用5种加成型硅橡胶,以ISO 4823标准金属模具制取印模,对印模进行高温高压灭菌(135℃,212.8 kPa)25 min,灭菌前后用测量显微镜测量标志线,评价印模的尺寸稳定性和细节再现性.结果 高温高压灭菌前后5组试件表面标志线的线性变化率绝对值均小于0.8％;每种加成型硅橡胶印模灭菌处理前后表面标志线长度的差异均无统计学意义(P＞0.05).灭菌前后5组试件表面均可观察到完整长度的标志线.结论 5种加成型硅橡胶印模均可耐受高温高压灭菌处理,灭菌处理对其细节再现性和尺寸稳定性没有显著影响.     

藻酸盐印模材料水粉比及印模放置时间对模型精度的影响

目的 :观察水粉比及印模放置时间对藻酸盐印模材制取全牙列模型精度的影响。方法 :制取一个标准下颌牙列金属母模。用 3种水粉比 ( 2 3∶10 ;30∶10 ;33∶10 )调拌藻酸盐印模材料 ,制取 30个模型 ,每组 10个。再用两种水粉比 ( 2 3∶10 ;30∶10 )各制取 30个印模 ,分别放置不同时间 ( 0、15、30min)灌制模型。用测量显微镜测量模型各标志点的距离 ,所得数据进行统计分析。结果 :①不同的水粉比制备印模 ,当水粉比为 33∶10时 ,66间线段长度的标准差异常增大 (s =0 .2 0 6) ,其余线段的长度变化无明显统计学意义 (P >0 .0 5 ) ;②随着放置时间的延长 ,印模出现收缩变形 ,统计有显著差异 (P <0 .0 1)。结论 :①适量增加水粉比 ,模型仍可获得较高的精度 ,但随着水粉比的增加 ,印模强度下降 ,容易变形 ;②随着放置时间的增加 ,印模收缩变形     

消毒液浸泡消毒对藻酸盐印模尺寸稳定性影响的评价研究

目的评价用三种消毒液浸泡不同时间后,四种藻酸盐印模的尺寸稳定性。方法采用符合YY1027国家行业标准和ISO 1563国际标准的标准试验装置,制取四种藻酸盐印模材料的标准印模,每种材料制取6组,每组5个印模,共120个印模。分别用2%戊二醛和84消毒液浸泡30分钟和40分钟、邻苯二甲醛消毒液(Ortho-phthalaldehyde,OPA)浸泡20分钟和30分钟。使用工具显微镜测量浸泡消毒处理前后各组印模的标志线长度,比较浸泡前后印模线性尺寸变化率,并对所得结果应用SPSS10.0软件进行统计学分析。结果①使用2%戊二醛、84消毒液浸泡处理前后,全部印模均发生显著膨胀形变(P<0.05),且形变随浸泡时间的延长而增大。②使用邻苯二甲醛消毒液浸泡处理前后,全部印模均发生显著收缩形变(P<0.05),且形变随浸泡时间的延长而增大。③不同材料的印模之间尺寸变化率的差异有显著性(P<0.05)。登士柏翡翠Jeltrate的形变率最小。④不同消毒液不同浸泡时间处理对印模尺寸稳定性影响的差异有显著性(P<0.05)。在相同浸泡时间时,使用2%戊二醛浸泡处理的印模形变率比使用84消毒液浸泡处理的印模形变率要小。结论①消毒...     

浸泡消毒对海藻酸盐印模三维尺寸稳定性影响的评价

目的评价海藻酸盐印模分别接受2%酸性戊二醛、2%碱性戊二醛、2%强化中性戊二醛、84消毒液(有效氯含量为0.3%)的30分钟浸泡消毒处理后的三维尺寸稳定性的变化。方法采用同一个标准模型制取印模。实验分为四个消毒处理组,不处理组作为对照组。采用三维坐标扫描机分析消毒处理后的印模灌制出模型的尺寸改变,精确度可达0.001mm。结果除了2%强化酸性戊二醛处理组各项指标均与对照组没有显著性差异以外(P>0.05),其余三个消毒处理组均在水平向、垂直向和角度等方面与对照组出现显著性差异(P<0.05)。结论2%酸性戊二醛浸泡消毒30分钟,对海藻酸盐印模的三维尺寸稳定性没有显著性影响。     

三种形状藻酸盐印模尺寸精确性分析

目的:本实验旨在比较使用藻酸盐印模材料制取不同形状物体阴模过程中的尺寸精确性.方法:分别使用藻酸盐印模材料制取正方体,圆柱体、三角体阴模,并用电子数显卡尺测量灌注的普通石膏、硬石膏、超硬石膏模型试件的尺寸,并与实物尺寸进行比较分析.数据进行ANOVA(α=0.05).结果:圆柱体印模尺寸变化较大,正方体印模尺寸变化较小,而三角体印模尺寸变化居中(P＜0.05).正方体的普通石膏灌注阴模组,硬石膏灌注阴模组和超硬石膏灌注阴模组的尺寸变化百分率分别是0.044%,0.128%,0.370%.圆柱体的普通石膏灌注阴模组,硬石膏灌注阴模组和超硬石膏灌注阴模组的尺寸变化百分率分别是0.745%,0.665%,0.369%.三角体的普通石膏灌注阴模组,硬石膏灌注阴模组和超硬石膏灌注阴模组的尺寸变化百分率分别是0.557%,0.595%,0.561%.结论:三种形状中正方体对藻酸盐印模制取的尺寸变化影响较小,三角形次之,圆柱体变化较大.     

玉洁新消毒液调拌藻酸盐印模材临床效果评价

目的:应用玉洁新消毒液调和藻酸盐印模材料拓取牙颌模型后,评价印模表面细菌含量及模型尺寸精度的变化。方法:取印模前用无菌棉拭子在志愿者前牙舌侧窝采样,而后用玉洁新消毒液漱口,3min后应用玉洁新消毒液调和藻酸盐印模材料取模,于印模所对应的前牙舌侧窝处取样,4h内送检,接种于营养琼脂平皿,37℃培养48h,进行细菌定性分析。再以同一金属模型为母模,应用玉洁新消毒液调和藻酸盐印模材料制取10个印模,以超硬石膏灌模,比较石膏模型与母模之间指标线段长度差异。结果:(1)消毒前有细菌存在,消毒后印模细菌阴性培养率为100%。(2)经测量灌制的石膏模型与母模之间指标线段长度形变率为0.15%-0.18%。结论:结果显示从统计学和临床的观测,应用玉洁新消毒剂自体消毒印模所合成的石膏模型并不引起显著的尺寸改变。     

根管交叉角度对琼脂桩核印模制取完整性的影响

目的:以硅橡胶取桩法为对照,考察琼脂/藻酸盐联合法制取桩核印模的效果。方法:制作后牙双根管模具5个,设定不同根管交叉角度,分别为0°、10°、20°、30°、40°。以硅橡胶取模法为对照,应用琼脂/藻酸盐联合法制取桩核印模,在相同角度下分别用2种材料取模20次。对取出的印模进行评价,分析根管交叉角度对2种材料取模的影响。采用SPSS16.0软件包对数据进行统计学分析。结果:硅橡胶组各角度间取桩印模完整率无显著差异(P>0.05);琼脂组中,当根管间交叉角度为40°时,印模完整率(60%)较0°组完整率(95%)及总完整率(83%)低,差异显著(P<0.05);当根管间交叉角度为40°时,琼脂法取桩完整率(60%)低于硅橡胶法(90%)(P<0.05)。琼脂法取桩总完整率(83%)显著低于硅橡胶法(96%)(P<0.05);琼脂/藻酸盐法取桩的完整性与根管角度呈显著负相关(r=-0.901, P=0.037)。结论:当磨牙根管之间角度较小时,使用琼脂/藻酸盐联合法制取桩核印模可满足临床需求,当角度大于30°时,建议使用硅橡胶类材料。硅橡胶类材料取磨牙桩核印模完整率整体上优于琼脂。     

新洁尔灭调拌消毒法对藻酸盐印模材料尺寸稳定性的影响

目的：研究藻酸盐印模材料与4种不同浓度新洁尔灭消毒液调拌对印模尺寸稳定性的影响。方法：用0.05%、0.10%、0.15%、0.20%新洁尔灭消毒液调拌藻酸盐印模材作实验样本,以蒸馏水调拌相同材料制取印模做对照,分别制取15组试件印模。用超硬石膏灌模,60min后脱模,石膏模型静置2h后,用高精度数显游标卡尺测量石膏模型,进行统计学分析。结果：实验组模型与对照组模型尺寸稳定性无显著性变化,4组实验组间比较,亦无统计学上的显著性差异。结论：0.05%、0.10%、0.15%、0.20%新洁尔灭消毒液调拌藻酸盐印模材不影响印模精度,0.20%新洁尔灭可作为临床上印模常规消毒方法。     

两种调拌方法对藻酸盐印模材尺寸稳定性的影响

目的：比较2种调拌方式（人工,机调）下,2种藻酸盐印模材（金玛克专用,普通藻酸钾）精度的变化。方法：按调拌方式和印模材种类分4组：A组为自动调拌机调拌金玛克印模材;B组为自动调拌机调拌藻酸钾印模材;C组为人工调拌金玛克印模材：D组为人工调拌藻酸钾印模材。采用特制的金属模具取模后灌注石膏模型,再测量模型尺寸变化差值,所得数据进行统计分析。结果：采用机调的2种印模材精度均好于人工调拌组;而金玛克专用印模材在机调组中的精度好于普通藻酸钾印模材;人工调拌下金玛克印模材与普通藻酸钾印模材的精度差值差别并不显著。结论：使用自动调拌机调拌的印模材精度优于人工调拌,而以专用的印模材精度最高。     

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