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目的探讨正畸临床牙釉质的最佳酸处理时间。方法从2005年大连市口腔医院外科门诊200颗正畸减数拔除的双尖牙中挑选出13颗作为样本,随机抽取其中3颗作为对照,未作酸处理。10颗进行酸处理的实验牙用约1mm宽的蜡条沿牙冠颊轴嵴作分界线,蜡条覆盖部分作为对照区。扫描电镜下观察未酸蚀的对照牙、实验牙对照区和经过15s和60s酸蚀处理后的实验牙釉质表面形态。结果镜下观察结果显示:酸蚀前釉质表面多较为光滑,似云片、积雪状外观;酸蚀后在小部分样本釉质表面中看到典型的蜂窝样和鹅卵石样形态。构成比显示60s酸蚀组较15s酸蚀组釉质丢失量多。结论60s酸蚀组较15s酸蚀组釉质丢失更严重,为了尽可能地减少酸蚀粘接对牙釉质的损害,正畸临床可将酸蚀时间适当减少。     

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目的比较5种不同方法预备根管后对根尖1／3根管壁的清洁能力。方法将2007年12月至2008年3月在大连市口腔医院颌面外科门诊拔除的60颗离体牙随机分为6组,每组10颗。各组的牙齿先使用Protaper进行根管预备,然后使用不同的方法处理根管壁,分别为：A组H2O2和生理盐水（对照组）、B组EDTA凝胶和5．25％的NACLO,C组超声波荡洗根管、D组Nd：YAG激光、E组超声波（蒸馏水）＋EDTA、F组：超声波（5．25％NAcL0）＋EDTA。完成之后将样本纵向剖开,扫描电镜观察根管壁的界面,比较根尖1／3根管壁的清洁程度和牙本质小管的状态。结果对照组（A组）牙齿根尖部被玷污层全部覆盖,未见开放的牙本质小管;各实验组（B、C、D、E、F组）牙齿根尖部根管壁玷污层不同程度被去除。B、C、D、E、F组根尖1／3玷污层的评分与A组比较,差异有统计学意义（P〈0．05）;5个实验组间根尖1／3玷污层的评分比较,D组与E组差异无统计学意义（P〉0．05）,其余各组间差异均有统计学意义（P〈0．05）。结论5种不同的方法在一定程度上可去除根尖部的玷污层,以超声波（5．25％NACLO）＋EDTA处理根管壁的效果最佳。     

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??Objective    To study the effect of a new titanium-copper alloy on the ultrastructure and genomic DNA of Porphyromonas gingivalis??P.g??. Methods    The titanium-copper alloy with copper content of 2%??5% and 10% were prepared and named Ti-2%Cu??Ti-5%Cu and Ti-10%Cu??respectively. The commercial pure titanium was used as the control??named cp-Ti. P.g were cultured on the surface of these materials and placed on the cell culture plate. The transmission electron microscope was used to scan the ultrastructure??and agarose gel electrophoresis was used to test the genomic DNA of P.g. Results    ??1??Under transmission electron microscope??the number of damaged P.g increased with the increase of copper content??the cytomembrane??cytoderm and cytoplasma of P.g in cp-Ti group were intact??the cytoderm and cytomembrane of P.g in Ti-2%Cu??Ti-5%Cu and Ti-10 %Cu were intact??blured and ruptured??and black precipitate and vacuole appeared in the cytoplasma.??2??The agarose gel electrophoresis showed??there was no difference in the amount of genomic DNA in control or experimental groups after being contacted by new titanium-copper alloy of P.g for 24h. Conclusion    Cupper ions in new titanium-copper alloy can damage the ultrastructure of P.g??but cann′t degrade the genomic DNA of it in short time.     

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??Objective    To observe the change of the surface structure of the arch wire due to different orthodontic bracket designs and ligations. Methods    In the dry environment the sliding of bracket  on the arch wire was simulated??and WDW20 & 0.5 electronic universal testing machine was used to provide uniform traction??the arch wire was scanned with SEM. Results    The wires investigated in this study had varying degrees of change??the MLF bracket with 0.2 mm ligation group had minimal changes to the arch wire surface. The scratches of arch wire surface distributed evenly on elastic ligation ring group??0.25 mm ligature wire was likely to cause the uneven distribution of stress. Conclusion    The different ways of ligation have different effects on morphological structure of the surface of the arch wire. The coarser ligature wires have bigger influence on the arch wire surface structure. Different orthodontic bracket designs will change the arch wire surface structure.     

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目的    比较3种机用镍钛根管预备器械 ProTaper、Mtwo、K3的根管预备效果。方法    选取2009年9月至2010年9月在中国医科大学口腔医学院口腔外科新鲜拔除的54颗上颌第一磨牙的近中颊根,根据其根管弯曲度分成A组（弯曲度≥20°）和B组（弯曲度< 20°）,每组再随机分成3个亚组（P组、M组、K组）,分别采用镍钛锉ProTaper、Mtwo和K3进行根管预备。预备前后,分别拍摄数字X线片,利用计算机图像分析软件生成预备前根管几何中心线并投影至预备后根管,测定根管偏移量及根管弯曲度的变化并且通过扫描电子显微镜观察其中的21例样本根管预备后碎屑和玷污层的分布及评分。结果    根管弯曲度≥20°时,根管弯曲起始处的根管偏移量及根管弯曲度减小量ProTaper组和Mtwo组均显著小于K3组（P < 0.05）;根管弯曲度<20°时,ProTaper、Mtwo、K3组间根管偏移量及根管弯曲度减小量差异均无统计学意义（P > 0.05）。扫描电镜下,P组、M组、K组3者根管冠1/3处碎屑评分差异无统计学意义（P > 0.05）,而在根中1/3及根尖1/3处评分差异有统计学意义（P < 0.05）,其中K组与P组、M组有显著差别（P < 0.05）,3组各部分玷污层评分差异均无统计学意义（P > 0.05）。结论    ProTaper、Mtwo、K3预备上颌磨牙轻度弯曲根管均具有良好的成形能力,Mtwo预备磨牙中、重度弯曲根管能更好维持原始根管走向;配合NaOCl和EDTA冲洗条件下,ProTaper和Mtwo对根管中下段的清理效果优于K3。     

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??Objective    To observe the effect of different concentration of silicon on demineralized enamel??and investigate its effect on remineralization of enamel demineralization. Methods   The research was performed in laboratory of School of Stomatology??Jilin University from April to August 2014. Enamel specimens were placed in lactic acid gel for one week. Then all specimens were  randomly divided into 5 groups after we confirmed that artificial enamel caries were formed by SEM. Then the five groups of demineralized model were respectively placed in the remineralization solutions whose concentration of silicon was 0??0.5 × 10-6??1 × 10-6??8 × 10-6 and 16 × 10-6. All specimens were removed after three weeks. The remineralization effect of the enamel surface were evaluated by scanning electron microscopy??SEM??. Results    Different concentration of silicon had an effect on promoting remineralization of demineralized enamel??especially when the concentration of silicon was 8 × 10-6. With the increase of silicon concentration??the remineralization of enamel demineralization increased when the concentration of silicon was 0.5 × 10-6??1 × 10-6 and 8 × 10-6. When the concentration of silicon increased to 16 × 10-6??its remineralization decreased. Conclusion    Silicon has an effect on promoting remineralization of demineralized enamel, and the remineralization effect is the best when the concentration of silicon is 8 ×10-6.     

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目的研究比较Er,Cr:YSGG激光预备与传统牙钻预备离体牙Ⅴ类洞对光固化复合树脂边缘微渗漏的影响。方法于2007年3月至7月,在中国医科大学实验设备处和中国医科大学口腔医学院中心实验室,将30颗离体前磨牙随机分为3组制备Ⅴ类洞:牙钻预备加37%磷酸处理组,单纯激光预备组,激光预备加37%磷酸处理组,每组10颗牙。经冷热循环染色后,采用染料渗入和扫描电镜方法观察充填体微渗漏情况。结果壁及龈壁处,染料渗入结果显示,牙钻预备加37%磷酸处理组的染料渗入评分最小,与其他两组比较差异有统计学意义(P<0.05),而单纯激光预备组与激光加37%磷酸处理组之间差异无统计学意义。充填体边缘微缝隙宽度的结果显示,单纯激光预备组的边缘微缝隙宽度最大,与其他两组比较差异有统计学意义(P<0.05),而牙钻预备加37%磷酸处理组与激光预备加37%磷酸处理组之间差异无统计学意义。结论Er,Cr:YSGG激光预备处理Ⅴ类洞不能增加光固化复合树脂与牙体组织的结合,减少微渗漏的发生;而应用激光加37%磷酸可以取代传统牙钻加37%磷酸进行窝洞预备。Er,Cr:YSGG激光预备离体牙Ⅴ类洞对光固化复合树脂边缘微渗漏的影响研究还有待于继续进行。     

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??Objective    To study the adhesive and invasive potential of PG0352 mutant strain interacting with KB cell. Methods    This study was carried out at Center Laboratory of School and Hospital of Stomatology??China Medical University from July to December 2014. Porphyromonas gingivalis??P. gingivalis??W83 or PG0352 mutant strain and KB cells were cocultured by MOI 100??1 for 2 h. Transmission electron microscopy was used to see whether P. gingivalis W83 and PG0352 mutant strain existed in KB cell. P. gingivalis in the coculture medium were removed??and P. gingivalis??which adhered to and invaded KB cell were released after lysis KB cells and then P. gingivalis were coated to the BHI plate. The invasive ability of P. gingivalis W83 and PG0352 mutant strain was measured by means of an antibiotic protection assay. Results    Both P. gingivalis W83 and PG0352 mutant strain adhered to and entered KB cells. ??15.559 ± 2.020??% P. gingivalis W83 and ??9.309 ± 1.750??% PG0352 mutant strain adhered to KB cell??and ??0.651 ± 0.287??% P. gingivalis W83 and ??1.517 ± 0.233??% PG0352 mutant strain  invaded into KB cell??both with statistical difference. Conclusion    Both P. gingivalis W83 and PG0352 mutant strain can adhere to and enter KB cell. Compared to P. gingivalis W83??less PG0352 mutant strain can adhere to KB cell and more PG0352 mutant strain can invade into KB cell.     

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??Objective    To estimate the three-dimensional effects of thermomechanical condensation by comparing the effects of thermomechanical condensation?? continuous-wave condensation and cold lateral condensation. Methods    The roots of sixty extracted human anterior teeth were divided into three groups randomly after preparation. After root canal filling with the three techniques?? thermomechanical condensation ??group A?? n=20???? continuous-wave condensation ??group B?? n=20?? and cold lateral condensation ??group C?? n=20???? the teeth were scanned by high resolution micro-computed tomography ??micro-CT??. Then?? the teeth were sliced at 3 mm?? 6 mm?? and 9 mm from the apical foramen. The cross-sections were observed using scanning electron microscopy ??SEM??. The percentage of void area were measured using Image J image processing software?? and all measurements were analysed by SPSS 17.0 software. Results    Both micro-CT and SEM indicated that the percentage of void area in group A was equal to that in group B ??P > 0.05??. And the percentage of void area in both group A and group B were significantly lower than that in group C ??P < 0.05??. Conclusion    The three-dimensional effects of the thermomechanical condensation technique are equal to the effects of the continuous-wave condensation technique and are superior to the traditional cold lateral condensation technique.     

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目的探讨中药离子导入治疗颞下颌关节紊乱病(TMD)的临床疗效。方法将2000年11月至2007年11月大连大学附属中山医院确诊的TMD患者212例,随机分为试验组(中药离子导入组)109例,采用中药溶液湿热敷配合电脑中频药物导入治疗仪治疗;对照组(药物治疗组)103例,采用传统口服药治疗。治疗2周后对比观察临床疗效。结果试验组及对照组的治疗有效率分别为90.83%和78.64%,两组差异具有统计学意义,(χ2=6.13,P<0.05),试验组有效率明显高于对照组。结论中药离子导入治疗TMD是一种具有较好应用前景的治疗方法,为中药治疗TMD提供了一种新的给药途径。     

釉质酸蚀后牙齿横断面的扫描电镜观察

目的:观察用37%磷酸凝胶以不同酸蚀时间处理后的牙釉质在牙齿横断面上的形态改变。方法:选取因正畸需要拔除的健康上颌第一前磨牙30个,随机分为3组,每组10个。分别用37%磷酸凝胶,以15s、30s、60s时间对颊面进行处理。用扫描电镜对牙齿横断面上釉质形态改变进行观察,并对改变的深度进行测量分析。结果:不同时间酸蚀后的釉质均表现为沿釉柱方向的溶解,但各组的溶解程度不同,15s组表现为间断的,深浅不一的溶解,30s组和60s组则表现为连续的、较均匀一致的溶解。在60s内,平均酸蚀深度随处理时间延长而加深。结论:釉质酸蚀后在牙齿横断面上的形态表现较为单一。15s组比30s组和60s组的溶解形态出现的密度低。     

釉质酸蚀后牙面脱矿与再矿化的扫描电镜观察

目的:观察牙釉质酸蚀后在离体状态下和一段时间内在口腔环境中的结构变化,探讨牙釉质脱矿与再矿化的形态学改变.方法:选择因正畸需要拔除健康第一前磨牙病例10例,40个牙,使用YY0269-1995型酸蚀剂对拟拔除的第一前磨牙颊侧釉质酸蚀60 8,左侧上、下颌第一前磨牙为A组,A组再分为A1、A2组,A1组酸蚀后即刻拔除,制作扫描电镜观察标本,A2组,第一前磨牙酸蚀后即刻拔除,置37℃恒温蒸馏水中浸泡1个月后制作电镜标本观察.右侧上、下颌第一前磨牙为B组,第一前磨牙酸蚀后在口内存留1个月后拔除,用相同的方法进行观察,并比较A、B两组牙釉质形态学变化.结果:A组的牙釉质表面松软,不规则,多孔隙,表面呈蜂窝状改变;B组的牙釉质表面有大量矿物质沉积,孔隙变小,矿化物颗粒细小,沉积不均匀.结论:牙釉质脱矿后,在口腔环境中可发生再矿化,但矿化程度是有限的,提示在临床上应注意酸蚀时间及酸蚀范围.     

Circumferential continuity of perikymata in human dental enamel investigated by scanning electron microscopy

Abstract – Theoretically the perikymata may represent one of two possible configurations: closed circles or continuous spirals. In the present study one randomly selected perikyma groove in one randomly selected tooth (the mandibular first premolar of a 12-yr-old girl) was tracked around the circumference of the crown in the scanning electron microscope. It was found that the perikymata geometrically represented closed circles. The possibility of methodologic error was excluded.     

不同年龄离体牙牙釉质酸蚀后超微结构研究

目的 观察不同年龄组牙釉质酸蚀后的超微结构。方法 收集2012年3月至2013年3月在中国医科大学口腔医学院口腔外科拔除的牙齿24颗,分为乳牙组（9 ~ 12岁）、年轻恒牙组（10 ~ 14岁）、青年恒牙组（25 ~ 40岁）、老年恒牙组（60岁以上）。用酸蚀剂处理不同年龄组牙齿的颊侧牙釉质表面,各实验样本分别冲洗、固定、脱水、干燥、喷金,应用扫描电镜观察各组被处理表面的超微结构形态。结果 乳牙组釉质表面较粗糙,釉柱排列形态不规则,相同的酸蚀时间乳牙组的牙釉质脱矿比恒牙明显。年轻恒牙组可见明显的釉柱端凹陷,釉柱表层排列松散;青年恒牙组牙釉质表面排列规整、致密,未见釉柱端凹陷;老年恒牙组牙釉质成不规则的点隙、裂沟,原有的釉质结构部分消失,蜂窝状结构明显。结论 不同年龄组牙釉质抗酸能力及脱矿形式不同。     

Uncoated specimen of human enamel obeerved in the scanning electron microscope

Abstract – A1-mm-thick section of human premolar was acid etched and observed uncoated in the SEM at accelerating voltages of 3, 5, 10 and 15 k v . Prisms and interprismatic substance were easily distinguishable. Low-voltage operation (3 and 5 k v ) gave the best results. Specimen charging was detectable at 5 k v and caused reduced image quality at 10 and 15 k v . Application of silver paste did not reduce charging appreciably. Prolonged observation at high magnification (x 10 000) resulted in contamination of the specimen with consequent charging and reduced resolution. Dental enamel seems to be a material which is well suited when uncoated for obervation in the SEM. This may be due both to the high content of the relatively heavy atom calcium, giving good secondary electron emission, and possibly to a certain degree of conductivity caused by diffusible icons.     

正畸多次酸处理后牙釉质表面的扫描电镜观察

目的：通过扫描电镜观察正畸多次酸处理后牙釉质表面的结构变化。方法：以正畸临床即将拔除的正常第一双尖牙为实验样本,分为实验组和对照组。应用５０％ 的磷酸处理牙齿的颊面,时间为６０ｓ。对实验组样本分１、２、３ 次粘结托槽。按所设计的酸处理与粘结托槽的次数拔除该牙并固定,扫描电镜下进行观察。结果：镜下的观察显示,第一次酸处理后只是部分釉柱的轻度脱钙,蜂窝样结构少而不均匀。第二次酸处理后牙釉质表面蜂窝样结构密集而规则。经一、二次粘结后牙釉质表面残留的树脂均比较少,第三次粘结后牙釉质表面相对有较多的树脂残留。结论：第二、三次粘结托槽,仍会获得较好的机械性粘合。     

Scanning electron microscopy of attrited dentinal surfaces and subjacent dentin in human teeth

abstract – Attrited dentinal surfaces and subjacent dentin were examined in the scanning electron microscope. In a central area of the exposed surfaces the dentinal tubules were occluded, whereas peripherally most tubules were open. Deposits, apparently dental plaque, were observed on the exposed dentin as uneven, but often continuous, layers covering whole areas of the surfaces. Loss of dentin within delimited areas of the surfaces was observed. The resulting defects could hardly be related to attrition, and it seemed that they were caused by erosive or caries-like processes. The dentin subjacent to the attrited surfaces was characterized by mineralized inclusions in the dentinal tubules. The inclusions consisted of irregularly rod-shaped crystals forming a meshwork on the tubule walls. Other crystals were formed as prisms, seemingly rhombohedrons. Crystals which were hexagonal in cross-section were also seen. The exposure of the dentin also seemed to have influence on the organic content of the tubules. Thus, it appeared that ground substance was removed from the intratubular fibers permitting the observation of cross-banding typical of collagen at their surfaces. In some tubules the fibers seemed to be covered by mineral.     

Scanning electron microscopy of fluorideinduced disturbances on the enamel surface of rat molars

Abstract — Rats were given a single high dose of fluoride at the age of 5 days and killed after 24 h, 10 or 15 days. The maxillary Erst molars were prepared for scanning electron microscopic examination. It was concluded that a single dose of fluoride, preferentially affecting ameloblasts with a high secretory activity, leads to the formation of subameloblastic cysts and enamel hypoplasias covered with granular deposits.     

髁突骨上组织扫描电镜和透射电镜的比较研究

目的比较髁突骨上组织在扫描电镜（ＳＥＭ）和透射电镜（ＴＥＭ）下的不同表现特点。方法３只成年健康家兔左侧髁突断裂后用ＳＥＭ的方法观察断面的结构,右侧做常规ＴＥＭ检查。结果ＳＥＭ发现,髁突软骨细胞仪表面呈蜂窝样的球体,胞内有多个空泡存在：钙化的软骨细胞这种表面形态消失,不规则地皱缩。ＴＥＭ下,软骨细胞似透明软骨细胞的典型形态,有短小突起,周围有半透明的薄带。钙化的软骨细胞内细胞器明显减少,部分有坏死的表现。结论ＳＥＭ观察到的髁突软骨细胞表面特征可反映细胞内部的结构和变化。     

快速整体内收上颌前牙对犬牙根吸收影响的扫描电镜观察

目的研究牙槽外科辅助快速整体内收上颌前牙对实验犬前牙牙根的影响。方法建立牙槽外科辅助快速整体内收上颌前牙的比格犬动物模型后,连续加力12 d,速度0.5 mm/d,分别于加力停止并固定1 d,14 d,28 d后随机处死3只实验犬,拔出一侧上颌第三切牙,制备标本行扫描电镜观察。结果加力停止1 d及14 d后牙根吸收明显,停止加力28 d后,牙根吸收面积明显减小:牙根颈部28 d与1 d(t=25.075,P=0.014)、28 d与14 d(t=17.444,P=0.056)比较,差异有统计学意义;牙根尖部28 d与1 d(t=26.436,P=0.000)、28 d与14 d(t=18.229,P=0.003)比较,差异有统计学意义。结论牙槽外科辅助快速整体内收上颌前牙会造成一定程度的牙根吸收,随着加力停止后固定时间的延长,牙根吸收可明显修复。