不同年龄人牙釉质对龋敏感性研究

采用细菌培养人工龋实验技术比较了青少年牙釉质和老年人牙釉质对龋病的敏感性。结果表明老年人牙釉质比青少年牙釉质薄，但脱矿改变是相似的。因此，可以认为老年人牙釉质与青少年牙釉质对龋病的敏感性无明显的差异。     

Reconstruction of curved mandibular angle defects using a new internal transport distraction device: an experiment in goats

A new internal distraction device, comprising a square-bodied bow, a transport plate, a traction mechanism, and two stabilisers, was developed to allow transportation of bone around an arc. Eight adult goats were studied. A curved mandibulectomy 3cm long was made on the mandibular angle. The distractor was implanted to restore the defect. The bone was distracted at a rate of 1mm per day after a 5-day latent period. Distraction lasted 25 to 32 days. Curvilinear distraction was successful in six of the eight goats. After consolidation periods of four or eight weeks, smooth curved bone masses were restored in the distracted areas. Radiographically, there was considerable bone density in the distraction area and opaque columns streamed in the direction of distraction. Histological examination showed membranous bony regeneration in the restored bone. These results suggest that restoration of curved bone defects using the new internal transport distraction device was feasible in goats.     

口腔念珠菌带菌与感染状态分离菌株的RAPD分析

目的 :研究念珠菌种之间及不同来源白念珠菌菌株之间的基因型相关性。方法 :对口腔白念珠菌病原菌、共生菌及非白念病原菌分别进行表型和RAPD分析。结果 :白念珠菌与非白念珠菌的RAPD带型存在差异 ,相似系数在 5 1.7%。共生菌与病原菌RAPD带型未见差异。白念珠菌种内相似系数大于 70 % ,菌株间存在DNA多态性。结论 :共生白念珠菌与病原菌未见RAPD带型差别 ,提示对口腔念珠菌病的防治应重视宿主因素在发病中的作用。     

牙种植数字化全景X线片失真率的临床评价

目的:了解数字化全景片失真率的大小以及在临床效果评价中的指导意义。方法:对术前使用统一直径钢珠的放射模板56个修复病例162个种植体拍摄数字化全景X线片,应用Cliniview5.1分析软件对各部位钢珠进行测量3次,取均值。了解拍摄后影像中钢珠的变化情况。结果:采用数字化全景X线片技术可观察到上下颌骨不同区域钢珠失真率与标准钢珠直径差异很小,失真率范围为0.2%￣2%,不同区域钢珠测量值之间有明显差异(P〈0.05〉):下颌前牙区与下颌双尖牙区、下颌前牙区与下颌磨牙区、下颌双尖牙区与上颌磨牙区、上颌磨牙区与下颌磨牙区钢珠测量值之间存在显著性差异。结论:数字化全景X线片对拟种植部位骨量进行评估可得出准确的数据。尽管不同区域钢珠测量值之间存在差异,但并不影响其测量值应用于临床的准确性。     

OSAHS与无睡眠呼吸障碍老年腭咽及其周围组织结构的MRI比较研究

目的研究睡眠呼吸暂停低通气综合症(OSAHS)与无睡眠呼吸障碍的老年男性腭咽及周围组织结构的三维形态差异.材料与方法70岁以上老年男性18名,根据夜间多导睡眠监测结果,8人AHI＞10,定为OSAHS组(T1组);10人AHI≤10,为无睡眠呼吸障碍组(T2组).所有受试者均行磁共振(MRI)检查,对两组腭咽及周围组织的MRI测量结果进行比较.结果①OSAHS组腭咽体积、截面积明显小于无睡眠呼吸障碍组;②与无睡眠呼吸障碍组相比OSAHS组腭咽左右径明显小、前后径/左右径之比明显大.③OSAHS组腭咽侧壁厚明显大于无呼吸障碍组、脂间距也明显小于后者.④两组的腭咽前壁厚度、后壁厚度、脂肪垫体积、舌体积、软腭体积没有显著差异.结论老年男性OSAHS患者由于腭咽侧壁增厚及咽旁脂肪垫的挤压,使腭咽左右径减小、截面积减小且形状趋圆,腭咽体积也减小.     

骨髓间充质干细胞移植促进大鼠下颌骨牵张成骨的实验研究

目的:探讨大鼠下颌骨牵张间隙内移植自体骨髓间充质干细胞,促进骨痂形成的可行性。方法:选用54只雄性SD大鼠,密度梯度离心法分离骨髓间充质干细胞(MSCs)。所有大鼠行右侧下颌骨牵张;并于术后随机分为试验和对照2组。牵张结束时,实验组牵张间隙内注射自体MSCs;而对照组只注射等量生理盐水。分别于固定期第2、4、8周分3批处死大鼠,进行放射学、组织学观察,并对骨组织形态计量学参数进行统计学分析(t检验)。结果:放射学和组织学观察表明,2组牵张间隙内均形成了骨痂组织,但实验组新生骨组织显著多于对照组。计量学分析也显示,各时间点实验组新生骨量(NBV1和NBV2)和新生骨小梁宽度(TNT)均显著高于对照组(P<0.01)。结论:牵张间隙内行自体骨髓MSCs移植,可有效促进新骨形成,缩短固定期;该方法对众多的颅颌面外科畸形的矫治极具价值。     

ICRF154,加热对腺样囊性癌ACC-2细胞放射增敏的实验研究

目的研究ICRF154和加热对腺样囊性癌ACC－2细胞放射增敏的作用。方法以腺样囊性癌ACC－2细胞作为实验模型，用新抗癌药ICRF154在乏氧条件下研究该药的放射增敏性以及加热对放射的增敏效应。结果在0．2mmol／L浓度和2个小时作用时间下，ICRF154对ACC－2细胞有放射增敏作用，增敏比为1．22、放射后加热43℃，30分钟对ACC－2细胞有显著的放射增敏作用，增敏比为1．51。用上述浓度和作用时间ICRF154，作用于ACC－2细胞后进行照射，照华后即行加热43℃，30分钟，增敏比为1．67，表明ICRF154和加热的放射增敏作用有加成效应。结论ICRF154的放射增敏机制可能与其抑制拓扑异构酶Ⅱ，从而抑制DNA损伤的修复有关。     

非调和型正畸粘接剂的粘接强度考察

采用一种自制的非调和型正畸粘接剂,考察了牙釉质与正畸托槽在五种实验条件下的粘接抗张强度。结果表明该粘接剂不需调和,操作时间充裕,具有足够的初始粘接强度和长期粘接强度,其平均粘接抗张强度大于7MPa,特别适用于对多个正畸附件的粘接。     

Analysis of the degradation of a model dental composite

Dental composites undergo material property changes during exposure to the oral environment and may release compounds of potential toxicity, such as bisphenol A. Degradation of dental composites was studied in a simplified overlayer model in which bisphenol A diglycidyl methacrylate (BisGMA) was covalently bound to a porous silicon oxide surface. It was hypothesized that the chemical structure of this overlayer would allow release of bisphenol A, BisGMA, and the decomposition products thereof, upon exposure to water for an extended period. Liquid chromatography mass spectrometry found leaching of intact BisGMA and several degradation products that contained the bisphenol A moiety from the overlayer into distilled water after 2 wks of aging. The absence of bisphenol A release from the overlayer reduces concerns regarding its potential health risk in dental composites. Nevertheless, health concerns might arise with respect to BisGMA and the leached degradation products, since they all contain the bisphenol A moiety. Abbreviations: BisGMA, bisphenol A diglycidyl methacrylate; HPLC, high-performance liquid chromatography; LCMS, liquid chromatography mass spectrometry; MA, methacrylic acid; MPS, 3-(trimethoxysilyl) propyl methacrylate; m/z, mass-to-charge ratio; and TIC, total ion chromatogram.     

基质金属蛋白酶-7和c-myc在口腔鳞状细胞癌中的表达和意义

目的研究基质金属蛋白酶-7(MMP-7)与c-myc在口腔鳞状细胞癌组织中的表达及其意义。方法应用免疫组化EliVisionTM法分别检测MMP-7和c-myc在49例口腔鳞状细胞癌和5例正常口腔黏膜上皮中的表达情况。结果1)MMP-7和c-myc在口腔鳞状细胞癌组织中的阳性表达率分别为83.7%和77.6%。2)在不同病理分级、不同临床分期和有无淋巴转移的口腔鳞状细胞癌组织中MMP-7阳性表达率的差异有统计学意义(P<0.05)。3)在不同病理分级和有无淋巴转移的口腔鳞状细胞癌组织中c-myc阳性表达率的差异亦有统计学意义(P<0.05)。4)口腔鳞状细胞癌组织中MMP-7和c-myc的表达呈正相关(P<0.05)。结论MMP-7和c-myc在口腔鳞状细胞癌组织中均有高表达,在口腔鳞状细胞癌的发病过程中,其高表达具有协同效应,共同促进口腔鳞状细胞癌的发生和发展。