N-乙酰半胱氨酸对牙本质粘结剂生物相容性的影响

目的：探讨N-乙酰半胱氨酸（NAC）对牙本质粘结剂体外细胞毒性的影响。方法：制备两种粘结剂SingleBond和Prime＆Bond NT的细胞培养基浸提液,采用四唑盐显色（MTT）比色分析法,在添加/不添加N-乙酰半胱氨酸的情况下测定浸提液对3T3细胞生长的影响;光镜下观察细胞的生长情况。结果：两种粘结剂浸提液均有显著的细胞毒作用,细胞相对增殖率下降（P〈0.05）;在添加NAC的情况下,浸提液的细胞毒性被逆转,细胞相对增殖率与正常对照组无显著性差异（P〉0.05）,细胞形态接近正常。结论：NAC能改善两种粘结剂的体外细胞毒性,为今后发展生物相容性更优良的牙本质粘结剂奠定研究基础。     

人牙齿切片器官培养模型的建立

目的建立人牙齿切片体外器官培养模型。方法收集年轻人健康前磨牙或第三磨牙,用慢速切锯制备2mm厚的牙齿横切片,将切片用含1%琼脂糖的半固体培养基包被后采用Trowel器官培养方法在体外培养2～14天,对培养切片的细胞及组织形态进行组织学观察。结果实验成功的将牙齿切片在体外培养了两周,成牙本质细胞在培养一周之内能够很好的维持原来的形态。一周之后成牙本质细胞逐渐萎缩,细胞密度减小。结论实验成功的建立了人牙齿切片体外器官培养的模型,为后期进行组织损伤和修复、第三期牙本质的形成等方面的研究奠定了基础。     

牙切片器官培养模型的建立与应用

牙切片器官培养模式是一种有效的在体外保持了牙本质牙髓复合体生物学特性的实验方法,可用于进行各种生物性,物理性,化学性组织损伤和修复的研究。本文就牙切片器官培养模型的建立方法和实验应用进展作一综述。     

5种牙本质粘结剂的细胞毒性研究

目的比较Clearfil S3 Bond和Single Bond,Clearfil SE Bond,XenoⅢBond,G Bond对L929细胞活力的影响。方法小鼠成纤维细胞L929在Clearfil S3 Bond,Single Bond,Clearfil SE Bond,XenoⅢBond,G-Bond五种牙本质粘结剂的不同体积分数浸渍液(100%、50%、25%、12.5%)作用不同时间(24 h、72 h、120 h)后,倒置相差显微镜观察细胞形态变化,MTT法测定细胞相对增值率(RGR);用5级毒性分类法评级,并进行统计分析。结果 5种牙本质粘结剂在不同体积分数浸渍液的作用下,L929细胞形态均发生不同程度的变化。在72 h、120 h后,12.5%Clearfil S3 bond组和Clearfil SE Bond组的RGR值显著高于其它各组的RGR值(P<0.05)。结论 5种牙本质粘结剂的体外细胞毒性均较弱,其中第7代牙本质粘结剂Clearfil S3Bond和第5代牙本质粘结剂Clearfil SE Bond的细胞毒性显著低于其他几种粘结剂,可以安全地应用于临床。     

4种牙本质粘结剂对牙髓成纤维细胞毒性作用的比较

目的:对比研究4种第七代牙本质粘结剂对人牙髓成纤维细胞的毒性作用,初步探讨其生物安全性。方法:组织块培养法原代培养人牙髓成纤维细胞,免疫组织化学染色SP法鉴定细胞来源,采用四甲基偶氮唑盐比色法和浸提液法,双盲观察4种新一代牙本质粘结剂(G-Bond、i-Bond、xeno V、Clearfil S3Bond)的不同体积分数浸提液(12.5%、25%、50%、100%)作用不同时间(24、48、72 h)对人牙髓成纤维细胞的毒性作用。结果:4种牙本质粘结剂不同体积分数浸提液的作用下,人牙髓成纤维细胞形态均发生不同程度的变化。24、48 h时,xeno V细胞毒性影响较小,i-Bond细胞毒性影响较大,G-Bond与Clearfil S3 Bond细胞毒性无明显差异;72 h时,4种牙本质粘结剂对细胞毒性影响无明显差异。结论:4种牙本质粘结剂毒性趋于0～2级,随着作用时间延长,细胞毒性无明显差异。     

牙本质粘结剂对人牙髓细胞毒性的体外研究

目的：评价全酸蚀牙本质粘结剂和自酸蚀牙本质粘结剂对人牙髓细胞的毒性作用.方法：用人牙髓细胞为实验细胞,采用MTT比色分析法,对4 种牙本质粘结剂（Prime ＆ Bond NT,Single Bond,Xeno Ⅲ,iBond）进行体外细胞毒性研究.结果：不同浓度的粘结剂稀释液均可使人牙髓细胞的形态有所改变.4 种牙本质粘结剂的细胞毒性有显著性差异,且作用时间和浓度的改变对其细胞毒性有影响.全酸蚀粘结剂比自酸蚀粘结剂的细胞毒性强.结论：4 种牙本质粘结剂在体外对人牙髓细胞均有一定程度的细胞毒性,其中Single Bond的毒性较强,临床使用粘结剂时应合理选择粘结剂和掌握固化时间.     

体外牙胚培养在造牙本质细胞分化研究中的应用

体外培养的牙胚是研究造牙本质细胞分化的一个理想模型,本文从牙胚发育阶段的确定、培养条件、培养方法和培养结果等方面对这一模型加以综述,同时讨论了与发育中造牙本质细胞分化相关的细胞外基质、生长因子和基底膜等因素。     

iBond粘结剂、Single Bond粘结剂用于比格犬直接盖髓术的组织学评价

[摘要] 目的 对第七代牙本质粘接剂iBond和第五代牙本质粘接剂Single Bond及VLC Dycal的体内细胞毒性进行研究。方法 选择4只比格犬共72颗健康牙齿,在颊面制备Ⅴ类洞并在洞底做人工穿髓孔,然后分为3组,第1组和第2组分别用Single Bond和iBond,第3组用VLC Dycal盖髓作为阳性对照组。选取比格犬口内剩余健康牙齿24颗,不做处理作为阴性对照组。所有实验牙齿分别在盖髓后的第7、30天拔出,并进行组织学评价。结果 7 d时,3组材料均出现不同程度的炎症反应和组织紊乱,但其差异无统计学意义;30 d时,iBond和VLC Dycal两组的炎症反应较Single Bond组弱,其差异有统计学意义(P<0.05);3组材料均有不同程度的组织紊乱,其差异无统计学意义;所有样本未见有牙本质桥形成。结论 iBond对牙髓的刺激性较小;Single Bond对牙髓的刺激性较大。     

新型医用钛合金生物相容性评价

目的:评价新型医用钛合金Ti12.5Zr2.5Nb2.5Ta (TZNT)的生物相容性,并和3 种标准医用钛材料Ti6Al4V、Ti6Al7Nb和TA2进行对比.方法:通过细胞毒性试验观察细胞在TZNT、Ti6Al4V和Ti6Al7Nb合金离子析出培养液中的生长情况,计算在不同时间组的相对细胞增殖率,评价其毒性等级;通过皮下埋植试验观察4 种材料植入白鼠体内4 周和8 周的组织变化情况,计算炎细胞密度和纤维膜厚度的变化情况,评价其引起的组织反应程度.结果:TZNT、Ti6Al4V和Ti6Al7Nb在3 个时间组(2、 4、 6 d)的相对细胞增殖率均不低于100%,细胞毒性等级评定为0 级.和Ti6Al4V和Ti6Al7Nb相比,TZNT和TA2植入白鼠体内4 周和8 周后,无论是炎细胞密度还是植入物周围的纤维膜厚度均有所降低,引起的组织反应程度较低.结论:TZNT具有良好的生物相容性,是一种理想的生物医用钛合金.     

光固化粘结剂治疗牙本质敏感症的初探

采用单盲自身配对对照法，用光固化粘结剂和局部涂布氟化钠治疗牙颈部敏感症，平均疗效分别是７８．５％，６４．６％，经统计学处理ｐ＜０．０１，有高度显著性差别。故认为用光固化粘结剂治疗牙颈部牙本质敏感症优于氟化钠甘油糊剂脱敏法。实验组３月、６月、９月疗效分别为７４．２％、６１．３％、５８．７％，经统计学处理ｐ＞０．０５，表明其远期疗效较佳。     

Biocompatibility of dentin bonding agents

Abstract Dentin bonding agents were introduced to enhance the bonding of composite resins to dentin. Many commercial brands of bonding agents are now available for clinical use, and they are getting more and more popular. The third generation of dentin bonding agents seems to be more effective than earlier generations, although more complex to use. Dentin bonding agents have different chemical compositions, different mechanisms of actions, and different clinical application procedures and, conceivably, different biological effects on the pupal tissues are expected. The reported biological effects of dentin bonding agents ranged from none to severe, depending on several factors. Opinsion varied whether the inflammatory reactions associated with some bonding agents were due to the tooth restoration interface, or due to a combination of both factors.     

The bonding property and cytotoxicity of a dental adhesive incorporating a new antibacterial monomer

The incorporation of polymerisable cationic monomers has been attempted to generate dental resinous materials with antibacterial activity. This study tested whether the incorporation of a cationic monomer, methacryloxylethyl cetyl dimethyl ammonium chloride (DMAE-CB), into a commercial dental adhesive would influence the bonding property and biocompatibility of the parental adhesive, and whether DMAE-CB could leach out from the cured modified adhesive. Microtensile bond strengths of DMAE-CB-incorporated adhesive and its parental adhesive to dentin were compared. Dentin discs bonded with modified adhesive were incubated in artificial saliva at three different temperatures for 90 days to obtain eluents. The cytotoxicity of DMAE-CB monomer and adhesive eluents were tested with 3-(4, 5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cleavage assay (MTT assay). High-performance liquid chromatography (HPLC) was performed with the eluents of the modified adhesive. The results indicated that the incorporation of DMAE-CB into the dental adhesive did not adversely influence its bonding strength to dentin (P > 0·05). Although DMAE-CB monomer exhibited toxicity against L929 cells at the concentration of 2 μg mL(-1) or higher (P < 0·05), the eluents of DMAE-CB-incorporated adhesive did not show significant influence on cell growth (P > 0·05). Moreover, HPLC analysis detected four substances' peak baseline separation for the eluents of modified adhesives, which was identical to the eluent of the parental adhesive, indicating no detectable DMAE-CB monomer leaching even after soaking for 90 days. Those results suggest that DMAE-CB could be incorporated into the dental adhesive stably without compromising the bonding efficiency and biocompatibility of its parental adhesive.     

大鼠全牙器官体外培养模型的建立

目的 观察体外培养的大鼠全牙牙髓组织的生物学特征,为评估牙科生物材料的生物相容性提供实验模型。方法 新鲜拔除4周龄W istar大鼠上、下中切牙,采用Trowell支架培养法在体外培养,分别培养1周和2周进行组织学切片,HE染色后对牙髓组织进行组织形态学观察。结果 大鼠全牙器官在体外培养1周后,牙髓组织特别是成牙本质细胞能够很好的维持原来的生活状态。结论 大鼠中切牙全牙在体外培养可以成功培养1周,可为评价材料的生物相容性提供更加接近临床的实验模型。     

三种牙本质黏结剂对人牙髓细胞的细胞毒性

目的：比较不同固化时间下3种牙本质黏结剂（Dentin bonding agents，DBA）对牙髓细胞的细胞毒性，指导临床上合理选择黏结剂和掌握固化时间。方法：组织块培养法进行人牙髓细胞原代培养，并以免疫组织化学染色法鉴定。采用MTT比色分析法来评价3种DBA（Prime＆BondNT，Pb；XenoⅢ，Xe；AdheSE，Ad）的细胞毒性。结果：经ANOVA和Dunnett—t检验，与对照组相比，固化10s和40s的3种牙本质黏结剂对牙髓细胞均有毒性（P〈0．001），与浸渍液作用24h后一些牙髓细胞变圆、皱缩、失去细胞突起。固化10s的3种DBA中Ad对细胞毒性最大，Pb毒性最小；固化40s的3种DBA中Xe毒性最大，Pb毒性最小。与固化10相比，Xe和Ad固化40s可以减轻对牙髓细胞的毒性，经student—t检验，P〈0．01。结论：3种牙本质黏结剂对体外培养牙髓细胞均有一定毒性，延长固化时间可以减轻对牙髓细胞的毒性。     

Uptake of cadmiuin in developing rat teeth in organ culture

Abstract – Molar teeth from 9-day-old rats were cultured for 7 days in medium supplemented with 1 or 10 ppm Cd for 1 or 3 h or 7 days. After culture the Cd concentrations were measured separately from the mineralizing parts and the cell-containing tissues. The accumulation of Cd increased with the duration of treatment and the concentration used, being more intensive in the hard parts than the soft tissues of the teeth.     

Biocompatibility testing of a posterior composite and dental cements using a new organ culture model

Mandibular first molars from day 14 and 17 mouse embryos were cultured in vitro for 7 days in chemically defined Pratt's medium in a submerged culture system. Ameloblast and odontoblast polarization and morphogenesis occurred in the control tooth germs. Discs of Occlusin, Silicate, ChemFil, IRM and Dycal were exposed to the culture system as either fresh material, leached discs (by pre-incubation in media) or the leachate from the incubated discs. Their effects on dental differentiation were assessed histologically. Day 17 tooth germs were slightly more sensitive to the effects of the exogenous agents than day 14 tooth germs. In general, silicate and ChemFil were toxic, IRM was slightly less toxic and the major effect was from the leachate. Dycal was toxic but most of this effect resulted from pH changes in the leachate. Occlusin was the most biocompatible material tested. Only a very mild adverse effect was detected, and this appeared to be caused by an agent (not a pH change) released into the leachate.     

金属栅栏式腭器官培养模型的建立

目的建立金属栅栏式小鼠腭器官培养模型。方法选取妊娠14 d的孕鼠20只,采用金属栅栏静式培养法,将腭器官分别培养24和48 h,肉眼以及苏木精-伊红染色观察腭器官在体外的发育过程。结果腭器官发育良好,细胞形态正常。腭器官培养24 h后可见到中脊上皮;培养48 h后可见中脊上皮消失,腭突融合。结论本方法为研究腭裂发病机制提供了一个良好的体外模型。