无定形磷酸钙负载rhBMP-2纳米缓释体的制备及细胞毒性实验

[目的]制备无定形磷酸钙（ACP）负载重组人骨形态发生蛋白-2（rhBMP-2／ACP）纳米缓释体并观察其细胞毒性，为进一步体内植入提供实验依据。[方法]采用湿化学法合成rhBMP-2／ACP纳米缓释体；兔间充质干细胞（BMSCs）与rhBMP-2／ACP纳米缓释体进行体外复合培养，观察细胞在材料表面的黏附、增殖及功能表达，检测材料的细胞毒性。[结果]材料浸提液对兔BMSCs的生长无影响，其细胞相对增殖率在100．2％～102．5％之间，细胞毒性评级为0级；BMSCs于复合材料表面的黏附、生长速度、形态与对照组无明显差别。[结论]rhBMP-2／ACP纳米缓释体无细胞毒性，复合培养不影响BMSCs的正常生理功能，细胞相容性良好。     

纳米羟基磷灰石/聚酰胺的细胞相容性研究

目的对纳米晶骨修复和重建复合材料（n-HA／PA66）可能存在的潜在细胞毒性进行研究，为该材料应用于临床提供实验依据。方法参照GB／T16886.5-1997-ISO 10993-5：1992《医疗器械生物学评价细胞毒性试验体外法》的评价标准和要求，采用规定的L929细胞（小鼠结缔组织成纤维细胞），分别经直接接触、材料浸提液与细胞共培养等方式对n-HA／PA66复合材料进行细胞毒性测试，采用细胞形态观察法定性观察各组L929细胞在24、48、72h各时相点的细胞形态学变化，采用MTT比色法，测定各组1、2、4、7d L929细胞的相对增殖率来判别材料对细胞的毒性程度，并进行统计学分析比较。结果各实验组与阴性对照组两两比较对L929细胞的增殖差异均无显著性意义（P〉0．05）；各实验组与阳性对照组进行两两比较差异有显著性意义（P〈0．05）；细胞毒性为0～1级。结论n-HA／PA66与L929细胞相容性好，参照GB／T16886.5-1997-ISO 10993-5：1992标准属于安全范围。     

缺血预处理与急性心肌缺血/再灌注细胞凋亡及Bcl-2、BaX蛋白表达的关系

目的：研究缺血预处理对急性心肌缺血／再灌注细胞凋亡的影响及与Bcl-2,Bax蛋白表达的关系。方法：用在体心肌缺血／再灌注模型，将实验动物分为3组：对照组，缺血／再灌注组，缺血预处理组。分别用原末端标记（TUNEL）法测定凋亡细胞和用免疫组化法测定Bcl-2,Bax蛋白的表达。结果：与对照组相比，缺血／再灌注组增加凋亡心肌细胞的百分数（P＜0．01）及Bax蛋白的光密度值（P＜0．01），减小Bcl-2蛋白的光密度值（P＜0．01），与缺血／再灌注组相比，缺血预处理减小凋亡心肌细胞百分数（P＜0．01）及Bax蛋白的光密度值（P＜0．05），增加Bcl-2蛋白的光密度值（P＜0．01）。结论：缺血预处理通过调控Bcl-2/Bax表达而抑制心肌缺血／再灌注细胞凋亡。     

应用活性玻璃/rhBMP2构建生物活性材料支架的相容性研究

[目的]观察BG／rhBMP2构建的三维立体材料支架的细胞相容性、组织相容性，为进一步改善材料性能提供依据。[方法]体外培养的兔成骨细胞分别与BG和BG／rhBMP2材料支架联合培养，倒置显微镜、扫描电镜观察细胞黏附情况，MTT法分析细胞增殖情况；将复合培养的两种支架材料植入兔肌袋中，同期观察复合材料及空白对照组，分别于术后2、4、8、12周来评价其组织相容性。[结果]MTT法结果显示：随着培养时间的延长，各组细胞数量都明显增加，各时间点复合材料支架组细胞数高于空白对照组，差异有显著性意义，复合材料支架BG／rhBMP2在细胞贴壁时间和细胞活性方面均较单纯支架优良；两种支架材料在体内均无明显炎症反应。[结论]BG／rhBMP2是一种具有良好生物相容性的支架材料，有望在骨组织工程中得到广泛应用。     

纳米TCP/明胶/鹿茸多肽复合材料的生物相容性评价

目的 评价新型复合材料纳米TCP/明胶/鹿茸多肽的生物相容性,为其在骨缺损修复领域中的临床应用提供实验依据.方法 制备纳米TCP/明胶/鹿茸多肽复合材料,扫描电镜观察其形态.常规培养L929和NIH/3T3细胞,取对数生长期的细胞用于实验.通过急性毒性实验、溶血实验、细胞增殖实验和细胞毒性实验等研究该复合材料的生物相容性.结果 扫描电镜观察示复合材料微球直径约10μm,单个分散存在,微球表面存在纳米级孔洞.急性毒性实验结果显示,实验动物在观察期内一般状态良好,无惊厥、瘫痪和死亡等毒性反应,给药前、后体重无明显变化,该复合材料无急性毒性.溶血实验结果显示溶血率均<5%,符合医用生物材料的溶血实验要求.细胞增殖实验结果显示,不同浓度材料浸提液作用于NIH/3T3细胞均不同程度地促进细胞增殖,具有较好的生物学活性.细胞毒性实验结果显示,该材料细胞毒性为0级.结论 纳米TCP/明胶/鹿茸多肽复合材料具有良好的生物相容性.     

交联可调式抗结核药物缓释型纳米人工骨复合体的生物安全性研究

目的研究交联可调式抗结核药物缓释型纳米人工骨复合体的生物安全性。方法对交联可调式抗结核药物缓解型纳米人工骨复合体进行MTT细胞毒性实验、急性全身毒性实验、皮内刺激实验及致敏实验,并与对照组比较。结果该交联可调式抗结核药物缓解型纳米人工骨复合体MTT细胞毒性实验显示人工骨材料细胞存活率〉90%,细胞毒性1级。人工骨复合材料浸取液未引起豚鼠过敏。小鼠尾静脉注射后未出现明显全身毒性反应。结论交联可调式抗结核药物缓释型纳米人工骨复合材料无MTT细胞毒性,细胞相容性良好,并能够降低利福平直接给药的生物毒性,不引起全身毒性反应、皮肤/内刺激反应和急性过敏反应,具有良好的生物安全性。     

纳米β磷酸三钙/水凝胶复合材料促进骨再生的实验研究

目的 观察纳米β磷酸三钙（TCP）/水凝胶复合材料对骨再生的促进作用。方法 制作纳米β-TCP/甲基丙烯酸酰化明胶（GelMA）水凝胶复合材料。根据培养基的不同，分为空白对照组、GelMA组和纳米β-TCP/GelMA组，将大鼠骨髓间充质干细胞（BMSCs）与上述培养基共同培养。通过电镜观察、细胞增殖实验、碱性磷酸酶（ALP）染色，了解纳米β-TCP/GelMA复合材料的生物相容性及体外骨诱导活性。制作大鼠颅骨缺损模型，根据植入材料的不同，分为空白对照组、GelMA组和纳米β-TCP/GelMA组，术后4、8周取颅骨标本，通过Micro-CT扫描计算骨量分数和骨密度，对新骨形成情况进行组织学观察。结果 大鼠BMSCs在材料表面培养48 h，扫描电镜观察发现其在GelMA组和纳米β-TCP/GelMA组表面良好贴附及铺展；细胞与材料共培养1、3、5 d,BMSCs数量随时间推移不断增加，3、5 d时纳米β-TCP/GelMA组OD值最高（P 0.05）,7 d时与GelMA组相比，纳米β-TCP/GelMA组ALP表达明显增强。大鼠颅骨缺损区Micro-CT检查显示，纳米β-TCP/GelMA组骨量分数和骨密度高于空白对照组和GelMA组，差异具有统计学意义（P 0.05）；组织学观察结果显示，与空白对照组、GelMA组相比，纳米β-TCP/GelMA组新生骨更丰富。结论 纳米β-TCP/水凝胶复合材料具有良好的生物相容性，体外可促进大鼠BMSCs增殖和成骨分化，在大鼠颅骨缺损模型中具有良好的促进骨再生能力。     

聚乳酸/骨基质明胶多孔复合材料的生物相容性研究

目的探讨超临界CO2法制备的聚乳酸(poly lactic acid,PLA)/骨基质明胶(bone matrix gelatin,BMG)多孔复合材料的生物相容性,为其下一步骨缺损修复奠定基础。方法取小鼠成骨前体细胞MCT3T-E1细胞,分别与PLA/BMG多孔复合材料和PLA材料的浸提液培养7 d,每天采用MTT法测定细胞增殖率并进行细胞毒性分级。将PLA/BMG多孔复合材料与MC3T3-E1细胞复合培养,1、3、5 d于倒置相差显微镜下观察细胞生长及与材料贴附情况,5 d时取材行扫描电镜观察细胞贴附情况。将PLA材料(PLA组)及PLA/BMG多孔复合材料(PLA/BMG组)分别植于15只Wistar大鼠背部两侧皮下,术后大体观察大鼠一般情况,2、4、8周取材行组织学观察,测量包膜厚度、炎性细胞数及血管面积。结果体外细胞毒性检测示,培养1~7 d PLA/BMG组细胞增殖率均达100%以上,细胞毒性均为0级;而PLA组除1、3、5、6 d细胞毒性为0级外,2、4、7 d细胞增殖率均低于100%,细胞毒性级为1级。PLA/BMG多孔复合材料与细胞复合培养,可见随时间延长细胞逐渐长入材料孔隙内,细胞形态良好。材料皮下植入后,大鼠均存活至实验完成,切口愈合良好;PLA组材料被纤维结缔组织所包裹,周围组织及材料内含有较多炎性细胞,结缔组织向材料内部生长缓慢;PLA/BMG组纤维组织包裹不明显,结缔组织易于向材料中心长入且其中炎性细胞少见。两组各时间点包膜厚度差异无统计学意义(P0.05)。PLA/BMG组2、4、8周炎性细胞数均显著低于PLA组(P0.05),8周血管面积高于PLA组(P0.05)。结论超临界CO2法制备的PLA/BMG多孔复合材料具有良好的细胞和组织相容性。     

氨甲喋呤联合咖啡因对骨肉瘤细胞株的作用观察

[目的]观察氨甲喋呤联合咖啡因对骨肉瘤细胞株的作用.[方法]以国人骨肉瘤细胞株OS-732细胞为研究对象,根据析因试验设计原因,设1无药组(阴性对照组),2咖啡因组,3氨甲喋呤组,4咖啡因、氨甲喋呤联合用药组(混合用药组).培养一段时间后,分别采用MTY法细胞毒性试验和流式细胞仪(FCM)分析,观察3组药物对细胞的毒性(用残存细胞吸光度A值表示)及细胞周期的影响.[结果]FCM分析各组于48 h G2/M期细胞比例(%)为1组(23.210±0.416),2组为(23.120±0.440),3组为(28.770±0.531),4组(23.267±0.319),1组与2组间差异无统计学意义,其余各组间差异有统计学意义(P＜0.01).各组残存细胞吸光度A值为1组(0.411±0.006),2组(0.401±0.006);3组(0.304±0.007),4组(0.105±0.002),组间差异及交互作用有统计学意义(P＜0.01).[结论]氨甲喋呤与咖啡因具有协同作用,可增加氨甲喋呤对骨肉瘤细胞株的抑制率.     

纯钛种植体表面不同化学组成的TiO2涂层细胞毒性实验研究

目的：对纯钛表面不同化学组成的TiO2涂层可能存在的潜在细胞毒性进行研究，为该材料应用于临床提供实验依据。方法：参照GB／T16886和国家医药管理局颁布的行业标准YY／T0127的评价标准和要求，采用规定的L929细胞，经材料浸提液与细胞共培养方式对纯钛表面不同化学组成的TiO2涂层进行细胞毒性测试，采用MTT比色法，测定各组1、3、5天L929细胞的相对增殖率来判别材料对细胞的毒性程度，并进行统计学分析比较。结果：各实验组与阴性对照组两两比较对L929细胞的增殖差异均无显著性意义（P〉0．05）；各实验组与阳性对照组进行两两比较差异有显著性意义（P〈0．05）；细胞毒性为1级。结论：该TiO2涂层与L929细胞相容性好，参照GB／T16886和YY／T0127标准属于安全范围。     

新型美容牙科纤维／树脂复合材料桩钉的研制

目的 :研究高强玻璃纤维增强丙烯酸类树脂的力学性能 ;探索复合材料桩钉的成型方法。　方法 :用缠绕法制作预浸料 (S- GF/EAM树脂 ) ,用层压法制成单向纤维 /树脂复合材料 ,并测试其弯曲强度、弯曲模量和层间剪切强度。取适量的预浸料放入自制的模具中按复合材料成型工艺压制桩钉 ,并测试其纤维含量。　结果 :随着纤维含量增加 ,复合材料的弯曲强度和弯曲模量呈显著性增加 (P<0 .0 1) (弯曲强度 :1414.7± 6 4.5 Mpa,弯曲模量 :39.6± 1.6 Gpa) ,用模具压制的桩钉纤维含量为 (6 8.38± 1.6 7% )。　结论 :高强度玻璃纤维对丙烯酸树脂的弯曲性能具有增强作用。高强玻璃纤维 /EAM树脂复合材料桩钉可以满足临床需要。     

Prevention of root fracture using posts reinforced with fiberglass

(The aim of this study was to evaluate the fracture strength and mode of failure of endodontically treated teeth reconstructed with glass fiber reinforced posts. Twenty maxillary central incisors, extracted for periodontal reasons, were divided in 2 groups: gr. 1 - glass fiber posts, and gr.2 - control (endodontically treated but without posts). All samples were embedded in resin bloks and mounted in stainless steel cylinders for the compressive test. The force was applied on oral surface of the crown, until the failure occurred. The compressive loads at failure were recorded and compared with the statistical method Student t. The mode of failure of the specimens were also evaluated. The statistical analysis of the force values showed no significant difference between the groups. In conclusion, because of their low Young's modulus, the non-metallic posts made of resin composite reinforced with glass fibers have a protective effect on the dental tissues, the recorded mode of failure being very similar with the control group.     

不同桩核和粘结材料与牙体微渗漏关系的研究

目的:比较两种桩核常用粘结材料复合树脂、玻璃离子粘结后的根向微渗漏的大小,并进行分析和评价。方法:采用40颗离体上颌前磨牙作桩核制备,随机分为4组,每组10颗牙。A组:纤维树脂桩核复合树脂粘结组;B组:纤维树脂桩核玻璃离子粘结组;C组:铸造镍铬合金桩核复合树脂粘结组;D组:铸造镍铬合金桩核玻璃离子粘结组。采用微渗漏染料渗入法,印度墨汁作染料染色1周后透明技术处理,观察样本染色深度。结果:纤维桩核与两种粘结剂出现微渗漏的现象少于铸造镍铬合金桩核与两种粘结剂。结论:树脂粘结剂与牙体组织面以及粘结剂与桩核组织界面有较强的化学结合,封闭效果更好。     

玻璃纤维桩联合复合树脂修复牙体缺损的临床效果

目的 探究玻璃纤维桩联合复合树脂修复牙体缺损的效果。方法 选取2020年1月-2022年1月我院 收治的100例牙体缺损患者作为研究对象，随机分为对照组和观察组，各50例。对照组采用金属桩修复， 观察组采用玻璃纤维桩联合复合树脂修复，比较两组修复成功率、修复情况、临床指标、并发症发生 率。结果 观察组修复成功率高于对照组，差异有统计学意义（P＜0.05）；观察组牙体修复完整率、边缘 合适率高于对照组，牙体松脱率低于对照组，差异有统计学意义（P＜0.05）；观察组修复后美观度、固定 功能以及咀嚼功能评分均高于对照组，ALP检测数据低于对照组，差异有统计学意义（P＜0.05）；观察组 并发症发生率低于对照组，差异有统计学意义（P＜0.05）。结论 玻璃纤维桩联合复合树脂在牙体缺损患 者中可取得较优异的修复效果，且美观度较高，固定功能较强，能够改善患者的咀嚼功能，安全性较高， 值得临床应用。     

Effect of laser preparation on bond strength of a self-adhesive flowable resin

The aim of this in vitro study was to evaluate the effect of laser treatment on shear bond strength of a self-adhesive flowable resin composite to human dentin. Eighty extracted sound human molar teeth were used for the study. The teeth were sectioned mesiodistally and embedded in acrylic blocks. The dentin surfaces were ground wet with 600-grit silicon carbide (SiC) paper. They were randomly divided into two preparation groups: laser (Er:YAG laser, with 12 Hz, 350 mJ energy) and control (SiC). Each group was then divided into two subgroups according to the flowable resin composite type (n?=?20). A self-adhesive flowable (Vertise Flow) and a conventional flowable resin (Premise Flow) were used. Flowable resin composites were applied according to the manufacturer’s recommendations using the Ultradent shear bond Teflon mold system. The bonded specimens were stored in water at 37 °C for 24 h. Shear bond strength was tested at 1 mm/min. The data were logarithmically transformed and analyzed using two-way analysis of variance and Student–Newman–Keul’s test at a significance level of 0.05. The self-adhesive flowable resin showed significantly higher bond strength values to laser-prepared surfaces than to SiC-prepared surfaces (p?<?0.001). The conventional flowable resin did not show such differences (p?=?0.224). While there was a significant difference between the two flowable resin composites in SiC-prepared surfaces (p?<?0.001), no significant difference was detected in laser-prepared surfaces (p?=?0.053). The bond strength of a self-adhesive flowable resin composite differs according to the type of dentin surface preparation. Laser treatment increased the dentin bonding values of the self-adhesive flowable resin.     

Effects of post surface treatments including Er:YAG laser with different parameters on the pull-out bond strength of the fiber posts

This study aims to evaluate the effects of Er:YAG laser irradiation under different power settings on the pull-out bond strengths of fiber-reinforced composite posts. The crowns of single-rooted 60 teeth were removed by separation and the root canals were cleaned and shaped. Root canals were filled and post spaces were prepared. Sixty fiber posts were divided into five groups according to surface treatment methods as follows: an untreated control group, a sandblasting-coated group, and three groups undergoing surface preparation with Er:YAG laser under three different power settings (150, 300, and 450 mJ at 10 Hz for 60 s at 100-μs pulse duration). After root canal procedures, fiber posts were cemented to the root canal. After all of the specimens were set, pull-out tests were performed using a universal testing machine at a crosshead speed of 2 mm/min. The data were analyzed using one-way ANOVA and Tukey post-hoc test (p?p?相似文献   

玻璃纤维桩联合复合树脂修复青少年上前牙冠折

目的:观察玻璃纤维桩和复合树脂联合修复青少年上前牙冠折,随访2年并评价其临床效果。方法:对70例(88颗)青少年冠折上前牙行完善的根管治疗后,随机分成两组,35例患者45颗牙采用玻璃纤维桩和复合树脂联合修复,35例(43颗)采用螺纹钉和复合树脂联合修复。结果:随访期内玻璃纤维树脂桩冠修复组未见根折,1颗桩核松脱,螺纹钉树脂桩冠修复组3颗出现根折,1颗桩核松脱,2颗树脂边缘部分折裂,失访1例,两组修复效果差异有显著性(P0.01)。结论:对于根管治疗后青少年冠折上前牙,玻璃纤维树脂桩冠修复组成功率高于螺纹钉树脂桩冠组。     

Effect of Er:YAG laser pretreatment on bond strength of a composite core build-up material to fiber posts

Lasers in Medical Science - The study evaluated the micro push-out bond strength of resin material (Multicore Flow) to two types of fiber posts (FP), namely fiber-reinforced composite (FRC) Postec...     

In vitro and in vivo evaluation of a biodegradable chitosan-PLA composite peripheral nerve guide conduit material

Chitosan, a nature biodegradable material, has good biocompatibility but poor physical properties to serve as a nerve conduit. In this study, polylactic acid (PLA) was added to chitosan to form a composite material with improved intensity and elasticity, to be used as nerve conduits. The chitosan-PLA nerve conduits were fabricated with a mold casting/infrared dehydration technique. The constituent ratio of PLA and chitosan of 1:5 (v:v) was chosen to give the composite material both good mechanical properties and good biocompatibility. An in vitro cytotoxicity test showed that the chitosan-PLA material was not cytotoxic. The conduits were proved biodegradable and had many micropores to allow permeability. We evaluated chitosan-PLA nerve conduits as a guidance channel to repair 10 mm gaps in rat sciatic nerves. Nerve autograft and silicon conduits were used as the control. After 12 weeks, the regenerating nerves in three groups succeeded in passing through the nerve gap and reinnervating the muscle. Assessments, including ECG, histomorphometric evaluation, and weighing of triceps calf muscle, showed that the functional recovery of sciatic nerve was better in chitosan-PLA conduit group than in the silicon conduit group (P < 0.05), but the differences between the chitosan-PLA conduit group and the nerve autograft group were not significant (P > 0.05). Therefore, the chitosan-PLA guide proved to be a promising nerve conduit.     

Adhesion of composite resins to enamel irradiated by the Er:YAG laser: application of the ultrasonic scaler on irradiated surface

BACKGROUND AND OBJECTIVE: The clinical use of the Er:YAG laser in cavity preparation has become widespread. With respect to cavities prepared with the Er:YAG laser, restorations using composite resins and glass ionomer cements are common. The bond strength of current resin bonding systems to ground enamel is 14-30 MPa, whereas the strength to Er:YAG laser-irradiated enamel, regardless of the use or non-use of phosphoric acid etching is less than 10 MPa. STUDY DESIGN/MATERIALS AND METHODS: In this investigation, an ultrasonic scaler was tested as a technique to increase the bond strength of composite resins to the Er:YAG irradiated enamel surface. RESULTS: The application of the ultrasonic scaler significantly increased bond strength. CONCLUSIONS: The tensile bond strength in the groups treated with the ultrasonic scaler exhibited approximately twice the strength observed in groups treated with laser irradiation alone.