几种银汞合金替代材料微渗漏的体外实验研究

目的了解几种银汞合金替代材料的密合性能,为选择后牙充填材料提供参考依据.方法将25个新鲜离体无龋前磨牙于颊舌面制备50个V类洞,数字表法随机分为5组.分别采用Glacier前/后牙复合树脂、Beautifil氟化玻璃聚合体、Hi-dense银粉加强型玻璃离子、Surefil高密度后牙树脂、银汞合金等五种材料充填.用1%亚甲基蓝染液进行渗透试验,观圹察染料渗透深度并进行分析.结果5种材料均有程度不等的微渗漏出现.其中银汞合金充填组渗漏率最大,与其他各组渗漏率比较,具有显著差异(P＜0.05).Glacier.和Beautiful与其余各组相比渗漏率最小,具有显著差异(P＜0.05).结论 4种银汞合金替代材料在抗微渗漏的特性方面Glacier和Beautiful最佳,Surefil.和Hi-dense次之,银汞合金较差.     

Influence of resin-based restoration materials on cytotoxicity in gingival fibroblasts

Tooth-colored resin-based restoration materials have gained enormous significance in recent decades. Since the composites presently available still evidence various weaknesses, intensive research continues concerning them. In this study we tested the biocompatibility of six resin-based materials (Charisma, Solitaire, Definite, Tetric ceram, Ariston pHc and Compoglass) by means of cultured human gingival fibroblasts. Over a period of 9 days the cured resin-based materials were incubated with the fibroblasts. Cell growth, cell viability, and protein content was measured. The release of prostaglandin (PGE subset2) was also determined. There was a reduction of cell functions, related to the different resin-based materials. Protein content of the fibroblasts was significantly reduced (Kruskal Wallis test; p = 0.0001), depending on the material tested. Definite induced only minimal irritation, and there was correspondingly little contrast to the protein content of the controls. Solitaire induced the highest levels of irritation and the greatest reduction in protein content. Lactate production of fibroblasts also showed some significant reduction in contact with particular materials (p = 0.005). There were only small differences among the tested materials as concerns measured PGE subset2 release of the fibroblasts. The data suggest that the methods here employed may be quite useful in testing the cytotoxic potential of newly developed resin-based materials     

齿科铸造用纯钛制作义齿支架的临床效果评价

目的：评价一种新的齿科铸造用纯钛制作总义齿基托及可摘义齿金属支架的临床效果。方法：选择就诊于北京大学口腔医学院修复科的牙列缺损或牙列缺失患者共60例,随机分为实验组和对照组（各30例）,分别采用齿科铸造用纯钛（日进株式会社,日本）与Wironit钴铬合金（BEGO公司,德国）铸造局部义齿支架或总义齿基托,于义齿戴用后1周、1个月和3个月进行复诊,检查患者佩戴义齿的临床效果,评价义齿的安全性、强度、适合性。结果：采用的齿科铸造用纯钛或钴铬合金制作总义齿基托或者可摘局部义齿支架,两种材料在安全性、强度和适合性方面无显著差异。结论：所采用的齿科铸造用纯钛可以用于临床制作总义齿基托及可摘局部义齿支架。     

Fatigue cyclic loading test of an auro-galvanoforming ceramic bridge

Background In dental clinics, dentition defects are commonly restored with conventional porcelain-fused-to-metal fixed bridges. However, Ni-Cr alloy ceramic fixed bridges are known to have several drawbacks such as marginal coloration of the neck, low casting precision and, most seriously, poor biocompatibility. These problems could be circumvented by using noble metal ceramic bridges; however, one negative issue related to the conventional noble metal ceramic bridges is its high price due to the use of a large amount of gold for pontic. Therefore, an auro-galvanoforming ceramic bridge would be ideal to retain the advantages of a conventional material, yet reduce the amount of noble metal used. This study aimed to investigate whether any destructive changes occur to the auro-galvanoforming ceramic bridge under a fatigue cyclic loading test. Methods On standard models which the left maxillary first premolar is lost and with the cuspid teeth and the second premolar as the fixed bridge abutment teeth, six maxillary auro-galvanoforming ceramic bridges and six corresponding nichrome ceramic jointed crowns were made as group A, six nichrome ceramic bridges and six corresponding nichrome ceramic jointed crowns were made as group B （control group）. And then all specimens were fixed and tested on a fatigue cyclic loading machine; the changes occurring to the surfaces of occlusal contact with large functional area and to the porcelain-metal interfaces of the nichrome primary copings margins were observed through a scanning electron microscope （SEM）. Results In 120 hours＇ continual observation, none of the specimens had porcelain coating fractures or scraping occurrence and all of the porcelain coatings had been kept intact under sinusoidal cyclic loading with the load range of 120-200 N and frequency of 5 Hz. Conclusions Auro-galvanoforming ceramic bridges exhibited excellent fatigue strength in the fatigue cyclic loading test and may satisfy the clinical demand in theory, while the practical application shall be     

口腔金合金、钴铬合金、无锌银汞、含锌银汞合金间电偶电流的测定及临床意义

目的：测定异种合金咬合接触时产生的电流值。方法：在人工唾液中体外模拟异种合金瞬间咬合接触时的回路,浸泡初记录各偶对的电位及15个瞬间接触电流值。模拟人体夜间睡眠继续浸泡8 h后以同样方法又得到15个电流值。结果：初浸时,金合金/钴铬合金偶对产生的电流值最大,达6.17 μA;而浸泡8 h后,金合金／含锌银汞、金合金／无锌银汞偶对与其他偶对的电流值间比较,差异有显著性(P<0.05);偶对浸泡8 h前后比较,钴铬合金/无锌银汞合金偶对的电流值差异无显著性(P>0.05),始终处于最低水平。 含锌银汞合金的电位较负,而且实验中始终为阳极,被加速腐蚀。结论：金合金／钴铬合金、金合金／含锌银汞合金、金合金/无锌银汞合金均产生较高的电流值,若存在于口腔中,会有一定危险。钴铬合金/无锌银汞合金偶合时产生电流值小,临床上可酌情应用。银汞合金中锌的含量不同,影响着合金的耐腐蚀性能。     

银汞合金粘结充填的实验研究

目的 :对窝沟封闭剂作为银汞合金充填的粘结剂进行实验研究。方法 :采用新鲜离体牙常规处理后将其分为A、B两组 ,其中A组 (实验组 )在充填汞合金前洞壁周围涂以薄层粘结剂 ,随即充填汞合金。B组 (对照组 )常规充填汞合金。经处理后采用扫描电镜和次甲基蓝浓度测定的方法评价其疗效。结果 :无论是扫描电镜观察 ,还是次甲基蓝浓度测定 ,均证实窝沟封闭剂做粘结剂的汞合金充填组的微漏明显减少 (P<0 .0 5 )。     

不同材料治疗老年人牙根龋的效果对比研究

目的观察不同材料充填治疗老年人根面龋的临床效果,寻找一种有效的治疗方法。方法将245例(323颗)老年人根面龋患者分为三组:A组(n=102颗)用玻璃离子充填治疗;B组(n=115颗)用光固化复合树脂充填治疗;C组(n=106颗)用银汞合金充填治疗。1年后分别观察充填后的有效率。结果A组、B组、C组充填总有效率分别为87.25%、63.48%、80.19%。A、C组疗效明显优于B组(P均<0.01)。结论玻璃离子水门汀、银汞合金充填修复老年人根面龋的效果明显优于光固化复合树脂。对于前牙的根面龋,美观要求高,视野好的,可用玻璃离子水门汀充填,对于后牙的根面龋,美观要求不高,视野较差的,可用银汞合金充填。     

Preparation and biocompatibility of tissue-engineered scaffold materials based on collagen.

OBJECTIVE: To prepare a tissue-engineered scaffold material using collagen as the matrices and to study the blood compatibility and tissue biocompatibility of this material. METHODS: Physical, chemical and physical/chemical methods were used for the crosslinking of the collagen. RESULTS: Dynamic blood clotting tests indicated that the blood clotting index (BCI) of the crosslinked collagen materials prepared by different means decreased as their contact with the blood was prolonged, and the collagen material obtained after crosslink through 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide method showed the highest BCI after contact with the blood within certain length of time. Hemolysis ratios of all the crosslinked collagen materials were shown to be much lower than 5%, well conforming to the requirement of biomaterials. Scanning electron microscopy showed that the platelets attached to the surface of the crosslinked collagen materials, having a fairly small number, were not morphologically distorted. CONCLUSION: The collagen materials obtained by the 3 crosslink methods have good blood compatibility. The cells grow well on the surfaces of the materials, indicating their good biocompatibility.     

两种牙科金属材料细胞毒性及对L929细胞Bax和Bcl-2表达的比较

目的 :通过检测牙科常用金合金及镍铬合金的细胞毒性及两种金属材料浸提液对小鼠成纤维细胞L929凋亡相关蛋白Bax和Bcl-2表达的影响,来研究金属离子与L929细胞凋亡的关系,探讨在分子水平上评价材料生物相容性的方法。方法:应用金合金(A组)及镍铬合金(B组)的浸提液培养小鼠成纤维细胞L929,以含10%胎牛血清的RPMI1640培养基做为阴性对照(C组),采用四甲基偶氮唑盐微量酶反应比色法(MTT法)评价2种金属材料的细胞毒性,采用免疫组化法及ELISA法(酶联免疫吸附实验)检测2种金属材料对L929细胞Bax和Bcl-2蛋白表达的影响。结果:2种材料的细胞毒性均为0级;镍铬合金组Bax/Bcl-2表达的比值高于阴性对照组及金合金组,差异有统计学意义。结论:镍铬合金浸提液可引起小鼠成纤维细胞L929凋亡相关蛋白Bax表达及Bax/Bcl-2比值增高,这一结果可能为将来在分子水平上建立评价生物材料生物相容性的方法提供新的思路。     

Biocompatibility evaluation of chitosan-g-polyvinylpyrrolidone]

OBJECTIVE: To evaluate the biocompatibility of chitosan-g-polyvinylpyrrolidone as a new scaffold material. METHODS: The material was tested and measured for water absorption and contact angle, followed by evaluation of the biocompatibility by implantation into rabbits and in vitro cultured with the corneal epithelial cells. RESULTS: The water absorption rate of the material reached 1 100% with contact angle of 83-86. The results of implantation revealed partial degradation of the material 3 months after implantation, and much collagen and numerous corneal stromal cells appeared on the material without obvious inflammation reactions. In vitro coculture with epithelial cells showed good adhesion of the cells to the material which induced no obvious cytotoxicity. CONCLUSION: The novel chitosan derivative has excellent biocompatibility and can be used as a tissue scaffold material.     

PGE2通过EP2受体激活cAMP-PKA-CREB信号通路上调SnoN的表达而促进CCLP1细胞的增殖

目的:探讨前列腺素E2(prostaglandin E2,PGE2)对人胆管上皮癌细胞CCLP1增殖能力影响的作用机制。方法:用PGE2、EP1～4 4种受体激动剂、AC激动剂Forskolin、PKA抑制剂H89、cAMP拟似物db-cAMP处理CCLP1细胞,通过RT-PCR、Western blot、WST等实验检测SnoN mRNA、SnoN蛋白等表达水平、CREB蛋白磷酸化水平以及CCLP1细胞增殖能力的变化。结果:10μmol/L PGE2处理CCLP1细胞24 h后,SnoN mRNA的表达水平与对照组相比上升了22.5%(P<0.01),SnoN蛋白的表达水平上升了35.6%(P<0.05);10μmol/L EP受体激动剂处理CCLP1细胞24 h后,SnoN蛋白的表达水平与对照组相比明显增高,其中以EP2受体激动剂的作用最明显,上升了64.9%(P<0.05),细胞增殖能力上升了26.5%;10μmol/L AC激动剂Forskolin处理CCLP1细胞24 h后,SnoN蛋白的表达水平及CREB蛋白的磷酸化水平较对照组分别上升了25.1%、71.3%(P<0.05),细胞增殖能力也上升了...     

Plat铸造陶瓷的生物相容性试验

采用溶血试验、细胞毒性试验和急性短期口服毒性试验，对新型牙科材料ｐｌａｔ铸造陶瓷的生物相容性进行评价，结果表明：Ｐｌａｔ铸造陶瓷平均溶血率为３．９３％，按ＩＳＯ标准属于正常范围（＜５％）；Ｐｌａｔ铸造陶瓷对体外培养的Ｌ９２９细胞的生长、附着和增殖无明显抑制作用；将Ｐｌａｔ铸造陶瓷生理盐水悬浮液给小白鼠灌胃，动物未出现全身毒性症状，生长发育未受到不良影响。     

人工气管材料体外细胞毒性和生物相容性研究

目的 :对自行研制的人工气管材料进行体外细胞毒性和生物相容性研究 ,以便为该植入材料应用于临床提供实验依据。方法 :参照 ISO10 993- 1:1992医疗器械生物学评价标准和要求 ,对人工气管材料进行了体外细胞与材料共培养试验、细胞毒性试验、溶血试验、急性全身毒性试验、致敏和热源试验。 结果 :(1)人工气管材料表面的细胞黏附生长良好 ,该材料对体外培养的细胞形态不构成损害 ,对细胞的生长和增殖均无明显抑制作用 ,细胞增殖指数和增殖指数百分率与空白对照组比较无显著性差异 (P>0 .0 5 ) ,而与阳性参照材料组比较差异具有显著性 (P<0 .0 1) ;(2 )溶血率均低于 5 %的国家标准 ,在体外不引起溶血反应 ;(3)该组分材料也无急性全身毒性反应、致敏和热源作用。结论 :该人工气管材料无细胞毒性和热源作用 ,不引起溶血反应和急性全身毒性反应 ,对细胞形态、生长和增殖不构成损害 ,具有良好的生物相容性。     

银汞合金充填术后牙体组织受力分析

目的 观察5种基底料对银汞合金修复后牙体组织的应力分布和变形影响。方法 建立下颌第一磨牙二维有限元计算模型，基底厚度均为0．5mm，银汞合金厚2mm，采用合面中央集中加载，计算窝洞侧壁牙体组织上的应力分布和变形情况。结果 高应力集中和较大水平变形主要发生在洞底线角局部，低弹性模量基底材料可以加剧这一趋势。普通型氧化锌丁香油水门汀和氢氧化钙组局部的最大压应力集中是磷酸锌水门汀组的3-3倍，是玻璃离子和加强型氧化锌丁香油水门汀组的2倍。变形较磷酸锌水门汀组增加了40％，较玻璃离子水门汀增加了25％。结论 不同弹性模量的基底料对银汞合金充填后牙齿的强度有明显影响，弹性模量越低，局部牙体组织内产生的应力越高，断裂的可能性越大，从力学性能上看，磷酸锌水门汀是目前临床上常用基底料中最为理想的。     

EXPERIMENTAL STUDY ON APPLICATION OF CALCIUM PHOSPHATE BIOCERAMIC IN PERIODONTAL OSSEOUS DEFECTS

After cytotoxicity test of materials, the application of tricalcium phosphate ceramic (TPC) powder and calcium pyrophosphate ceramic (CPC) powder were evaluated histopathologically in dogs. 2-wall defects (crater) were created surgically in eighteen adult mongrel dogs and ceramic materials were placed into the dejects. On each side of jaw there remained a defect not filling with ceramic and served as control. The dogs were sacrificed at 2nd. 4th, 8th, 16th, 24th and 32nd postoperative week for histological evaluation. Histologically, all materials showed excellent biocompatibility and bone affinity. New bone was found directly deposited on the ceramic particles, and new bone grew more coronally in implant sites than in control sites. The bone affinity of TPC was better than that of CPC. These materials appeared to have osteoconductive effect. At 32nd postoperative week, there was still some remnants of ceramic. According to the results, the authors believe that calcium phosphate ceramic, especially TPC. has the potential to be an alternative to bone graft. The biocompatibility, function and bioresorbability of bioceramic are discussed.     

常用粘结剂与桩核材料的不同搭配使用微渗漏发生率及程度的比较

目的:评价不同核材料修复后的牙齿经铸造金属全冠修复后边缘微渗漏的发生率及程度,为临床选择合理的粘接材料、桩核材料及其配伍提供依据.方法:将90颗大小相似的完好磨牙随机分为9个实验组,分别为银汞核树脂粘接组、银汞核聚羧酸粘接组、银汞核玻璃离子粘接组、铸造核树脂粘接组、铸造核聚羧酸粘接组、铸造核玻璃离子粘接组、树脂核树脂粘...     

两种充填材料治疗磨牙食物嵌塞

目的探讨两种充填材料治疗磨牙食物嵌塞的临床疗效。方法选择食物嵌塞患牙,随机分成AB各两组,3MP60组和传统银汞合金组,对疗效结果进行比较。结果3MP60组的成功率为91%,86%;传统银汞合金组的成功率为86%,71%。结论3MP60治疗磨牙食物嵌塞疗效明显优于传统银汞合金。     

口腔用金属材料的磁共振伪影的检测

目的 检测口腔内常用金属材料在磁共振检查时是否产生伪影和伪影的严重程度;并比较不同检查序列对伪影的影响。方法 对22种25件口腔内常用金属材料做了磁共振成像测试,磁共振仪磁感应强度为1.5T,所用序列是梯度回波,部分材料加做自旋回波和快速自旋回波。结果 铸金片、银汞合金、银尖等11件试样无伪影;钛合金和金属烤瓷成品有轻度伪影;牙用固位钉、椿钉12件试样有严重伪影。牙用固位钉、镍铬合金冠等材料在快速自旋回波图像上伪影减轻。结论 部分口腔内金属材料会引起严重伪影,影响图像质量,所以在做口腔颌面部和脑部磁共振成像时,须引起重视。通过合理选择金属材料,合理选择成像序列和参数可以减轻伪影。     

前列腺素E_2对免疫细胞的调控影响

目的:通过观察前列腺素E2(prostaglandin E2,PGE)对外周血T细胞增值的影响,分析其对免疫细胞(Th1和Th2细胞)的调节作用及影响。方法:应用抗CD3和抗CD28单克隆抗体(mAb)与健康成人外周血单个核细胞(MNC),RPMI 1640,10%胎牛血清(FBS),加PGE2为观察组,不加PGE2为对照组,观察组加入不同浓度的PGE2,与对照组对比观察。结果:在加入不同浓度PGE2的情况下,T细胞增值的抑制率有时显增加,与PGE2浓度呈正相关。结论:前列腺素E2在免疫细胞的发育分化及免疫应答过程中起着重要作用。     

EP1受体介导PGE2对胆管细胞癌HuCCT1细胞MMP2表达和活性的影响

目的:探讨前列腺素E2(PGE2)对人胆管细胞癌HuCCT1细胞基质金属蛋白酶2(MMP2)的表达与酶活性的影响及与EP1受体的关系。方法:分别用PGE2、EP1受体激动剂或抑制剂、蛋白激酶C(PKC)抑制剂和钙离子螯合剂处理HuCCT1细胞,通过RT-PCR、明胶酶谱法检测MMP2的mRNA水平以及MMP2酶活性。结果:5μmol/L PGE2和5μmol/L EP1受体激动剂17-PT-PGE2处理组MMP2 mRNA的表达水平与对照组相比分别上升了89.14%(P<0.01)和163.89%(P<0.01);MMP2酶活性与对照组相比分别增强了69.11%(P<0.05)和117.65%(P<0.01);10μmol/L EP1受体抑制剂sc-51322处理后,MMP2 mRNA水平以及MMP2酶活性较PGE2处理组分别下降了47.74%(P<0.05)、84.58%(P<0.01);5μmol/L PGE2或5μmol/L 17-PT-PGE2处理稳定转染EP1R-pcDNA3的人胚肾细胞株HEK293细胞,MMP2的酶活性较对照组分别增强了36.07%(P<0.05)、61.59%(P<0.05)。...