奥硝唑用于感染根管消毒的细菌学研究

目的　观察和探讨新型抗厌氧菌药物奥硝唑消毒感染根管的抗菌效果。方法　选择感染根管患牙98颗,常规根管预备后,随机分为试验组(奥硝唑组)和对照组(甲醛甲酚组)各4 9颗。分别在根管预备前、预备后及封药后进行根管内细菌标本采样、培养、分离与鉴定,测定根管内细菌变化及检出情况,并观察封药后临床症状和体征的变化。结果　2组封药后,根管内细菌数量及检出率均较封药前明显降低( P<0 .0 5 ) ,根管内细菌数量及检出率比较,差异无显著性( P>0 .0 5 ) ,奥硝唑的近期临床疗效优于甲醛甲酚。结论　奥硝唑是一种较安全、有效的根管消毒药物     

慢性根尖周炎应用氢氧化钙根管内封药的临床疗效观察

目的:观察慢性根尖周炎患牙用氢氧化钙根管内封药的临床疗效。方法:选择100例慢性根尖周病变患者随机分为实验组和对照组各50例;观察组用氢氧化钙做根管内封药;对照组用甲醛甲酚做根管内封药,观察术后1周的临床及X线片表现,并分析评定临床疗效。结果:术后1周有效率比较,观察组为96%,对照组为86%;两组间疗效差异具有统计学意义。结论:氢氧化钙是较理想的根管内消毒剂。     

不同根管器械去除弯曲根管内充填物的效果研究

目的:比较新型旋转器械马尼GPR和ProTaper再治疗系统、手用H锉在根管再治疗中去除弯曲根管内牙胶的清理效果。方法:选取30个弯曲度为30°的透明树脂根管模块,根管长度为17mm。使用ProTaper Next机用镍钛器械预备至30/.06,热压胶垂直加压根管充填。样本随机分为3组(n=10),用以下方法配合丁克除溶剂去除根管内充填材料,A组手用H锉、B组ProTaper再治疗系统和C组马尼GPR,记录去除充填物所用总时间。从颊舌向和近远中向2个角度拍着数码X线片,使用Image J 2X图像分析软件分析根管内充填物残留量。用天平称量推出根尖孔碎屑量。结果:ProTaper再治疗系统组根管壁充填物残留量明显多于马尼GPR组和H锉组(P0.05)。H锉组操作时间明显高于ProTaper再治疗系统组和马尼GPR组(P0.05)。马尼GPR组推出根尖孔碎屑量明显少于ProTaper再治疗系统组(P0.05)。结论:马尼再治疗锉去除根管内充填物效率优于ProTaper再治疗系统和H锉,机用镍钛器械所用时间明显少于手用器械。     

不同赋形剂调制氢氧化钙对粪肠球菌消毒效果影响的体外评价

目的通过应用离体牙根管模型进行根管消毒模拟试验,就应用不同赋形剂调制的氢氧化钙糊剂对根管的消毒作用进行评价。方法选取因正畸拔除的单根管下颌第一前磨牙并进行根管预备,自釉牙骨质界处将离体牙截去牙冠,在距截冠处5 mm去除根尖,仅留5 mm长牙根,筛选获得经制备的模拟根管120个,随机分为4个试验组和2个对照组(空白对照组和阳性对照组),每组各20颗牙齿。将4个试验组及阳性对照组共100个根管建立粪肠球菌根管感染模型,4个试验组根管内分别放置使用生理盐水、甘油、葡萄糖酸氯己定、樟脑苯酚等4种赋形剂调制的氢氧化钙糊剂,阳性对照组20个感染根管中仅放置生理盐水,而空白对照组20个根管不接种细菌,仅置入无菌生理盐水。所有标本牙置5%CO2,95%N2,37℃环境下培养,每组分别于第3、7天取10个根管使用G钻均匀磨取根管内层牙本质粉末,置BHI液体培养基中培养72 h后,测定并分析各根管中残留细菌量。结果使用氢氧化钙糊剂消毒3 d时,4个试验组根管中残留细菌量均较阳性对照组有明显减少(P<0.01),葡萄糖酸氯己定组、甘油组和樟脑苯酚组的消毒效果好于生理盐水组;使用氢氧化钙糊剂7 d时,试验各组均有消毒效果,但生理盐水-氢氧化钙组牙本质小管中有少量均残留细菌,葡萄糖酸氯己定组、樟脑苯酚组的消毒效果差异无统计学意义。结论在离体牙根管消毒实验中,使用4种赋形剂调制的氢氧化钙糊剂均能有效抑制粪肠球菌生长,葡萄糖酸氯己定组、甘油组和樟脑苯酚组的消毒效果好于生理盐水组。     

脉冲Nd∶YAG激光在根管预备中的临床应用——与超声根管预备、传统手动根管预备比较

为了观察脉冲Ｎｄ∶ＹＡＧ激光在根管预备（以下简称根备）中的作用,我们用Ｎｄ∶ＹＡＧ激光辅助,对３０颗患牙进行根备,根备后即时根充。并与超声根备后即时根充、传统根备后即时根充比较,结果表明：激光组的术后疼痛反应少于超声组与传统组,远期疗效与超声组相仿,而优于传统组。     

新型激光光敏根管消毒剂在牙本质中渗透性的研究

目的:观察新型激光光敏根管消毒剂、甲苯胺蓝和亚甲基蓝在牙本质中的渗透效果,评价三种光敏剂在牙本质中的渗透性。方法:收集新鲜拔除的离体单根管牙90颗,根管预备后随机分为三组。每组30颗。A组为新型激光光敏根管消毒剂组;B组为甲苯胺蓝组;C组为亚甲基蓝组。A、B、C三组实验根管内分别用浸有饱和的新型激光光敏根管消毒剂、甲苯胺蓝和亚甲基蓝的棉捻在根管内停留60秒。沿牙体长轴颊舌纵向劈开,倒置荧光显微镜下观察并拍照,用Photoshop8.01软件测量三种光敏剂渗透入牙本质的平均深度。结果:新型激光光敏根管消毒剂在牙本质内的渗透平均深度为553.25μm,甲苯胺蓝在牙本质内的渗透平均深度为350.75μm,亚甲基蓝在牙本质内的渗透平均深度为168.25μm。结论:新型激光光敏根管消毒剂在牙本质渗透性明显优于甲苯胺蓝和亚甲基蓝,具有良好的牙本质渗透性。     

氯虫苯甲酰胺对草地贪夜蛾的毒力及田间防效

草地贪夜蛾Spodoptera frugiperda(Smith)是威胁粮食安全的重要害虫,本文测定了氯虫苯甲酰胺对草地贪夜蛾的室内毒力及田间防效,从中筛选出高效的施药方法和施药剂量,为当前草地贪夜蛾防治提供合理用药的参考。结果表明,在室内条件下,使用氯虫苯甲酰胺直接喷雾处理对草地贪夜蛾3龄和4龄幼虫毒力最高,LC_(50)值分别为0.42 mg/L和0.57 mg/L,使用0.5 mg/L 20%氯虫苯甲酰胺悬浮剂对草地贪夜蛾幼虫毒力较高,在处理后第5天均有超过90%的死亡率。在田间条件下使用氯虫苯甲酰胺对草地贪夜蛾幼虫有较好的防效,使用60.0 g.a.i./ha 0.4%氯虫苯甲酰胺颗粒剂喇叭口点施防治低龄幼虫防效较好,药后第1天、第3天和第7天低龄幼虫(1～3龄)的防效分别为90.3%、100%和100%,使用22.5 g.a.i./ha 20%氯虫苯甲酰胺悬浮剂喇叭口喷雾防治高龄幼虫(4～6龄)的防效较好,药后第1天、第3天和第7天高龄幼虫的防效分别为71.7%、84.5%和95.3%。     

绿豆子叶脱分化过程中RNA聚合酶的制备、特性及其活性的研究

绿豆(Phaseolus vadiatus L.)子叶切段在脱分化形成愈伤组织过程中,制备的染色质具有较高的RNA聚合酶活力,3天愈伤组织的酶活力高于5天和7天的;3天、5天和7天加激素脱柱依次分分化形成的愈伤组织,其酶活力均比不脱分化的高一倍以上, 用DEAE —纤维素酶部,依据层析洗脱性质和层析图谱及对d—鹅膏菌素的敏感程度,证明三个峰是RNA聚合I,II和III。     

巴氯芬注射液Beagle犬腰椎穿刺置管多次鞘内注射局部刺激性研究

目的模拟临床给药途径,Beagle犬腰椎穿刺置管多次鞘内注射巴氯芬注射液,观察其局部刺激性,同时进行犬行为学观察,为巴氯芬注射液安全性评价提供依据。方法12只Beagle犬分为假手术组,生理盐水对照组,巴氯芬给药组。行腰椎穿刺置管,使用单通道微量注射泵泵入给药,给药剂量为1000μg/d,生理盐水对照组给予生理盐水0.5mL,连续给药7d,恢复期7d。每日进行行为学观察,给药结束及恢复期结束时每组麻醉2只动物,取给药部位脊髓进行组织病理学检查。结果给药及恢复期期间动物行为未见异常,给药结束时各组均有部分动物观察到置管处表皮感染现象,进行局部消毒处理后在恢复期第3天恢复正常。组织病理学检查发现给药及恢复期结束时各组动物脊髓均可见血管周围炎细胞浸润或脊髓内钙盐沉积,各组无差别。给药结束时巴氯芬组1例动物脊膜处有肉芽组织形成,判定与置管操作有关。结论巴氯芬注射液Beagle犬腰椎穿刺置管连续7d鞘内注射,给药剂量为1000μg/d对脊髓无局部刺激性作用,动物行为也未见异常。     

新型激光光敏根管消毒剂在牙本质中渗透性的研究

目的：观察新型激光光敏根管消毒剂、甲苯胺蓝和亚甲基蓝在牙本质中的渗透效果,评价三种光敏剂在牙本质中的渗透性。方法：收集新鲜拔除的离体单根管牙90颗,根管预备后随机分为三组。每组30颗。A组为新型激光光敏根管消毒剂组;B组为甲苯胺蓝组;c组为亚甲基蓝组。A、B、C三组实验根管内分别用浸有饱和的新型激光光敏根管消毒剂、甲苯胺蓝和亚甲基蓝的棉捻在根管内停留60秒。沿牙体长轴颊舌纵向劈开,倒置荧光显微镜下观察并拍照,用Photoshop8．01软件测量三种光敏剂渗透入牙本质的平均深度。结果：新型激光光敏根管消毒剂在牙本质内的渗透平均深度为553．25μm,甲苯胺蓝在牙本质内的渗透平均深度为350．75μm,亚甲基蓝在牙本质内的渗透平均深度为168．25μm。结论：新型激光光敏根管消毒剂在牙本质渗透性明显优于甲苯胺蓝和亚甲基蓝,具有良好的牙本质渗透性。     

联合方法测量工作长度应用于颌骨囊肿受累牙根管治疗的研究

目的：研究颌骨囊肿受累牙根管治疗中采用联合方法测量根管工作长度的效果。方法：选取36 例颌骨囊肿受累患牙需术前 根管治疗的患者,共135 颗患牙,186 个根管,随机分为两组,实验组（93 个根管）采用电测法联合纸尖法测量根管工作长度,对照 组（93 个根管）则采用电测法联合X 线法测量根管工作长度。对比两组根管充填后的充填效果。结果：实验组的根管恰填率为 90.32%,高于对照组的79.57%（P＜0.05）。结论：采用电测法联合纸尖法测量颌骨囊肿受累牙根管工作长度,准确率高,根管充填 效果好且安全。     

ProTaper根管扩大系统联合镍钛K锉在老年磨牙根管术中的应用价值

目的:探讨ProTaper根管扩大系统联合镍钛K锉在老年磨牙根管治疗中的应用价值。方法:收集2012年2月~2013年10月在我院口腔科就诊的156例急、慢性牙髓炎及根尖周炎的老年患者的临床资料,共发现患牙193颗,随机分为3组,A组60颗,B组64颗,C组69颗。A组采用ProTaper手动根管扩大系统联合镍钛K锉预备根管;B组采用ProTaper机动根管扩大系统联合镍钛K锉预备根管;C组采用不锈钢K锉预备根管。对适充率、填充满意率、急症反应发生率进行评定。结果:A、B、C组的适充率分别为为94.02%(110/117)、93.80%(121/129)、62.22%(89/143);A、B、C组的填充满意率分别为96.58%(113/117)、96.12%(124/129)、58.04%(83/143);A、B、C组急症反应发生率分别为4.27%(5/117)、4.65%(6/129)、26.57%(38/143)。A、B两组在适充率、填充满意率、急症反应发生率方面相比,无统计学差异(P0.05),但分别与C组相比,均显著高于对照C组,差异有统计学意义(P0.05)。结论:ProTaper根管扩大系统联合镍钛K锉在老年磨牙根管治疗中的疗效显著。     

下颌第二恒磨牙C形根管的离体实验研究

目的：寻找一种预备C形根管的有效器械,提高下颌第二恒磨牙的治愈率。方法：选用80颗具有C形根管的下颌第二恒磨牙,选择四种器械进行根管预备,第一组用不锈钢K锉,第二组用不锈钢K锉和手用镍钛器械,第三组用机用镍钛器械,第四组用超声根管治疗仪,预备中均用3％双氧水和生理盐水交替反复冲洗根管,预备后用Vitapex糊剂和牙胶尖冷侧压方法充填根管,观察根充后X线片和根尖微渗漏情况,评价充填效果。结果：四种器械根充后微渗漏有明显差异（P〈0．05）。结论：不锈钢K锉和手用镍钛器械联合应用及超声根管治疗仪为预备C形根管的有效器械。     

高频电对感染根管消毒作用的初步实验研究

目的:初步验证高频电对感染根管是否具有较理想的消毒作用,并且与氢氧化钙药尖的消毒作用进行初步比较分析。方法:本实验制作10只家兔40颗门齿的感染根管动物模型,其中20颗用高频电消毒为实验组。20颗用氢氧化钙药尖消毒为对照组,消毒前后分别作需氧菌和厌氧菌培养并比较其消毒效果。结果:消毒前实验组和对照组各20个根管的需氧及厌氧菌培养全部阳性。实验组消毒后需氧菌3个阳性根管、厌氧菌2个阳性根管,消毒前后对需氧和厌氧菌杀灭作用的差异均具有极显著性(P<0.005)。对照组消毒后需氧菌13个阳性根管消毒作用的差异有显著性(P<0.05)。对照组消毒后厌氧菌11个阳性根管消毒作用的差异有极显著性(P<0.005)。实验组和对照组分别对需氧和厌氧2个菌种之间消毒作用的差异均无显著性(P>0.05)。实验组和对照组对需氧菌的消毒作用和对厌氧菌的消毒作用的组间差异均具有极显著性(P<0.005)。结论:高频电对感染根管内容物的消毒作用优于氢氧化钙药尖,具有临床应用的可行性。值得进一步研究。     

The effects of three different demineralization agents on osteopontin localization in adult rat bone using immunohistochemistry

Immunohistochemical localization of osteopontin, a phosphorylated acidic glycoprotein, was compared in adult rat femur fixed in 4% paraformaldehyde at 4° C for 48 h and demineralized at 4° C in ethylenediaminetetraacetic acid (EDTA), modified Jenkin's solution, or 15% formic acid, until radiographs indicated demineralization was complete. Formic acid was also evaluated at room temperature. EDTA solution (15 days) resulted in intense staining of osteocytes, periosteal osteoclasts and osteoblastic cells in osteonal bone. Osteoblasts were negative in the periosteum. No megakaryocyte staining was present; however, occasional neutrophils in the bone marrow were non-specifically stained. Demineralization in modified Jenkin's solution (16 days) showed osteopontin localization in bone matrix, hypertrophic and articular chondrocytes, and osteocytes. In cortical bone, almost all cement lines demarcating osteons showed very dense labeling. In the bone marrow, occasional megakaryocytes were immunopositive and neutrophils were non-specifically stained. Jenkin's produced non-specific staining of skeletal muscle and connective tissue. Formic acid demineralization (14 days, 4° C) resulted in osteopontin expression in osteoblasts, osteocytes, osteoclast precursors, bone matrix, osteoid, cement lines, and chondrocytes; osteoclasts, although present in very low numbers, were also positive. More labeled osteoblasts could be identified compared to Jenkin's demineralization. Also more intense non-specific staining of the bone marrow neutrophils was obtained than with Jenkin's. Harsh, rapid demineralization with formic acid (4 days, room temperature) produced a loss in antigenicity demonstrated by a reduction in staining intensity not experienced with the 4° C protocol; however, osteopontin was still localized in bone matrix and hypertrophic zone chondrocytes. These results indicate that demineralization is compatible with retention of immunoreactive osteopontin in adult rat bone. Both EDTA and formic acid demineralization produce excellent immunostaining and are preferred over the modified Jenkin's solution to minimize background levels of non-specific staining.     

The rate of calcium extraction during EDTA decalcification from thin bone slices as assessed with atomic absorption spectrophotometry

Summary The rate of calcium extraction with EDTA (ethylenediamine tetraacetic acid) from thin bone slices (300 m-2mm thick) was determined by aid of an atomic absorption spectrophotometer. A 0.5 mm thick bone slice was completely decalcified with 15% (0.40 M), 8% (0.22 M), and 4% (0.11 M) EDTA in 24 h, 3 days, and 5 days, respectively (vol. 15 ml, temp. 4° C, pH 7.4). At 37 and 60° C the speed of demineralization was slightly increased as compared with that at 20° C, while no difference was observed between 4 and 20° C. Bone slices with a thickness of 0.3, 0.5, 1 and 2 mm were decalcified-in the same order-in 24 h, 2, 3, and 5 days (8% EDTA, 4° C, pH 7.4). At pH 7.4, the decalcification rate was a little slower than at pH 5.0 and 8.5. Agitation did not affect the decalcifying velocity, nor did the volume of the agent, except when the volume was very small. The demineralization of ordinary bone, containing both compact and spongy bone, was found to be more rapid than that of homogeneous bone reported earlier. The acidic buffers and New Decalc^®, which served as reference substances, exerted a more vigorous decalcifying effect than EDTA. K formate/formic acid buffer, pH 3.15, demineralized a 1 mm thick bone slice in 24 h, and 2 days was needed with Na lactate/lactic acid buffer, pH 3.70. With New Decalc^®, pH 0.9, the corresponding demineralization was accomplished in 1.5 h. Atomic absorption spectrophotometer proved to be a useful tool in the evaluation of calcium extraction velocity from bone slices.     

Nd∶YAG激光对提高根管治疗术效果的作用机理探讨

用波长1.06μm,输出功率20W的Nd∶YAG激光照射根管壁后,常规根管糊剂+牙胶尖侧压法充填。对照组,直接根管充填。通过测量酚醛树脂在根管横截面中所占面积比值和染料渗入长度,发现实验组和对照组之间无明显差异(P>0.05)。认为单纯激光照射对根尖封闭能力的影响并不明显。激光照射在根管治疗术中的作用可能是通过其它途径。     

苗期土壤渍水对棉花恢复生长及光合生理的影响

以'中棉所41'为试验材料,采用盆栽方法,研究了苗期土壤渍水对棉花恢复生长及光合生理的影响.结果显示:(1)渍水5 d的棉苗经过10 d恢复生长,其根系活力、株高、叶面积、完全展开叶片数与对照差异不显著,但根系总长度仍比对照低11.1%(P<0.05);渍水10 d的棉苗经过10 d恢复生长,其根系活力、株高、叶面积、完全展开叶片数、根系活力均极显著低于对照.(2)渍水5 d棉苗经过10 d恢复生长,其光合速率、气孔导度、光饱和点、CO2饱和点、表观光最子效率、羧化效率以及叶绿素a、b含量与对照差异不显著;渍水10 d的棉莆经过10 d恢复生长,其光合速率、气孔导度、光饱和点、CO2饱和点、表观光量子效率、羧化效率以及叶绿素a、b含量仍显著低于对照.研究表明,棉莆经过5 d或10 d渍水胁迫后,均可以恢复生长,但随着渍水时间延长,恢复生长速度降低;在恢复生长过程中,生理活性恢复快于形态恢复;强光对于渍水后棉苗恢复生长具有明显的抑制效应.     

Rapid demineralization in acidic buffers

Summary The demineralization of routine histological specimens in buffers of weakly ionized organic acids, unbuffered formic acid, and EDTA was investigated. The rate of demineralization was measured by a chemical method and from radiographs. Lactate-containing buffers and buffers of formic acid with its potassium salt were more rapid in effect than any other agent. Acidic buffers and unbuffered formic acid produced rapid diffuse demineralization with secondary precipitation of calcium salts. Preservation of dental enamel in such buffers resulted from the significantly slower rate of enamel demineralization than that for bone and dentine. In rapid demineralizing agents the secondary salts were quickly redissolved while in slow buffers these salts persisted. Multivalent ions such as citrate and maleate slowed the rate of demineralization, and a citrate-containing buffer was the slowest of all the agents tested. Demineralization in EDTA exhibited a different pattern with the establishment of a well-defined front of demineralization without apparent reprecipitation. EDTA attacked enamel, bone and dentine at the same rate. An attempt was made to relate the observed rates of demineralization to current theories of the demineralization process.Supported by the British Medical Research Council