牙科复合树脂及其浸出成分的细胞毒性

目的：观察4种含有不同成分的牙科复合树脂的细胞毒性,通过高效液相色谱法分析其浸出的成分。材料和方法：将复合树脂（Z100,Solitaire 2,Filtek P60．Synergy）制备成圆盘状测试试样,采用Balb／C 3T3成纤维细胞进行细胞毒性实验。在37℃条件下．实验第一部分为细胞与树脂接触72h（直接法）,第二部分则是细胞与树脂的乙醇浸泡提取液接触24h（间接法）。用MTT法{[3（4,5二甲基噻唑2）2,5二苯基]四氮唑嗅盐法}检测细胞存活率。结果：牙科复合树脂及其乙醇浸泡提取液对Balb／C 3T3成纤维细胞有毒性作用。单因素方差分析显示直接接触和间接接触各组间的差异均有统计学意义（P〈0.001）。组间比较（Tukey检验．α=0.05）显示直接法检测Synergy的毒性显著低于其他树脂．Solitaire 2毒性显著高于其他树脂。但是．间接法检测则为Synergy的浸泡提取液毒性显著高于其他树脂的提取液。采用高效液相色谱法检测各树脂中Bis—GMA,TEGDMA．UDMA．bis-EMA以及双酚A的含量,结果显示上述成分存在与否和其浓度各不相同。结论：牙科树脂的细胞毒性水平与其化学成分、浸泡介质以及浸出的成分和量相关。     

玻璃离子、复合体、复合树脂对人牙髓细胞的细胞毒性试验研究

目的 :研究玻璃离子、复合体、复合树脂牙色材料对体外培养的人牙髓细胞的细胞毒性作用。方法 :采用MTT法测定上述 3种牙色材料的浸渍液对体外培养的人牙髓细胞的细胞毒性。结果 :与对照组相比 ,7d的牙色材料浸渍培养液对体外培养的人牙髓细胞有抑制作用 ,其中复合树脂的抑制人牙髓细胞的增殖有显著性 (P <0 .0 5 ) ;但 3d的浸渍培养液却呈现出不同的细胞毒性作用 :玻璃离子仍有一定的抑制细胞增殖作用 ,复合体基本无作用 ,而复合树脂却有显著的促进细胞增殖作用 (P <0 .0 5 )。结论 :牙色材料的细胞毒性作用与其牙色材料的种类相关。     

光固化复合树脂释放成分的检测方法及评价

光固化复合树脂是临床广泛使用的牙体修复材料,在光照发生聚合固化时,有部分单体未发生聚合,成为残余单体,残余单体在口腔环境中进行浸出释放,唾液、酶等也会引起树脂的生物降解从而释放一些成分,这些成分可能对机体组织形成一定的影响。目前有多种检测释放单体的方法,包括高效液相色谱法、液相色谱-质谱联用法、高效液相色谱-质谱联用法、气相色谱-质谱联用法等。该文从残余单体释放的原因及其对人体的影响、检测方法等方面作一综述。     

复合树指单体对人牙髓细胞毒性的研究

目的：评价复合树脂单体对人牙髓的毒性作用,探讨不同细胞系对检测敏感性的影响。方法：选用人牙髓细胞（ＬＳＣ）为实验细胞,以Ｌ－９２９小鼠成纤维细胞作为对照细胞系,采用ＭＴＴ比色分析法,对两种牙科用复合树脂单体（ＴＥＧＤＭＡ和ＵＤＭＡ）进行体外细胞毒性研究。结果：在低于ＩＣ５０的各浓度组中,ＬＳＣ细胞的生存率高于Ｌ－９２９细胞;ＭＴＴ比色法作为一种能定量检测牙科材料细胞毒性的有效方法,实验时应注重考虑     

可乐丽菲露AP-X复合树脂对人牙髓细胞毒性的研究

目的 通过细胞毒性试验，探讨可乐丽菲露AP-X复合树脂及其SEBOND粘接系统在临床上用于活髓牙窝洞直接修复术的安全性。方法选用年轻健康人新鲜离体牙髓，以组织块培养法及酶消化法进行原代培养。同时制备各材料样品，浸入DMEM培养基制取材料浸渍液。分别将各材料的浸渍液与第五代人牙髓细胞共同培养，以MTT法评价材料的细胞毒性。结果可乐丽菲露AP-X复合树脂的细胞毒性小于双组份玻璃离子水门汀Vitremer及复合树脂Z100，其差别具有统计学意义，与复合体F2000的细胞毒性无统计学意义的差别。可乐丽菲露的细胞毒性小于复合体F2000和复合树脂Z100对应粘接剂，且其差别具有统计学意义（P〈0．05）。结论可乐丽菲露AP-X复合树脂及其粘接剂的细胞毒性小于临床上现在常用的其他牙色类材料。     

抗菌剂对复合树脂综合性能影响的研究进展

复合树脂是目前临床上应用最多的口腔科修复材料,但其仍存在强度低、耐磨性差、易出现微渗漏和继发龋等缺点,因此有关提高复合树脂性能的研究从未停止。与其他修复材料相比,复合树脂表面细菌更容易黏附、聚集,进而形成菌斑生物膜。在复合树脂中添加抗菌剂已成为重要的手段,但抗菌剂的添加对复合树脂的力学、理化性能以及细胞毒性的影响需要进一步研究,文章就抗菌剂对复合树脂综合性能影响的研究进展做一综述。     

细胞凋亡检测方法的研究进展

细胞凋亡不仅是一种特殊的细胞死亡类型,而且具有重要的生物学意义及复杂的分子生物学机制。开展对细胞凋亡的研究,首先要解决的是方法学问题。本文对目前常用的研究凋亡的方法从定量、定性及凋亡基因活性测定方面进行概述。     

4种牙体修复材料对人牙髓细胞毒性的实验研究

目的：比较4种牙体修复材料--Dyract AP、Ceram X、Quixfil U及Surefil复合树脂对人牙髓细胞的生物学作用.方法：制备4种牙体修复材料的细胞培养基（DMEM）浸出液,采用四唑盐MTT比色分析法测定材料对人牙髓细胞生长的影响;通过扫描电镜观察人牙髓细胞在不同材料表面的生长情况.结果：人牙髓细胞在4种复合树脂浸出液作用下,细胞相对增值率（RGR）与对照组相比均有显著性差异（P＜0.05）,其中Surefil的RGR与其他3种材料相比有显著性差异（P＜0.05）,而Ceram X、Quixfil U、Dyract AP 3种材料之间RGR无显著性差异（P＞0.05）;扫描电镜观察到人牙髓细胞在4种材料表面均可贴附,且生长良好.结论：4种牙体修复材料均对牙髓细胞的生长无不良影响,具有良好的生物相容性.     

碘伏的细胞毒性研究

碘伏于50年代开始应用于临床以后,逐渐受到重视.特别是在1984年第三届国际抗感染会议上对碘伏的药理及临床应用进行了广泛的讨论,进一步推动该药在临床上的使用.作为一种新型、广谱、高效的消毒剂,以其确实的优点取代了一些临床上常用的消毒剂.本实验旨在研究碘伏对L929细胞的毒性作用,探索碘伏的浓度与作用时间对杀灭细胞的影响,为临床用药浓度提供理论依据.     

Long-term cytotoxicity of resin-based dental restorative materials

Highly filled composites, Ormocers (organically modified ceramics) and 'smart' materials have been developed to overcome the polymerization shrinkage problems of conventional composite materials. The purpose of the current study was to investigate the effect of longer-term (up to 8 weeks) ageing of these resin-based dental restorative materials and determine the effect of post-curing on cytotoxicity. Twelve discs of each material (Colombus/IDR, Definite/Degussa, Ariston pHc/Vivadent) were either light-cured (Lc) or light-cured and post-cured (Pc). For cytotoxicity testing, the discs were placed in contact with cell culture medium (DMEM) and incubated at 37 degrees C. Extracts from composite materials were collected after 24 h and weekly over a time period of 8 weeks. Cytotoxicity of the eluates to cultured fibroblasts (Balb/c3T3) were measured by the succinic dehydrogenase (SDH) activity (MTT assay) and the results expressed in percentage of negative controls (Teflon discs). The results showed that ageing significantly influenced the cytotoxicity of the materials. Except for Ariston pHc, materials were less cytotoxic after 8 weeks of ageing than they were in early intervals and post-curing was not generally useful in reducing cytotoxicity. The Ariston pHc was initially moderately toxic, but then become highly cytotoxic for 5 weeks before returning to initial levels. The current study demonstrated the importance of assessing the cytotoxicity of resin composite materials at multiple times.     

新型填料增强复合树脂耐磨性的研究进展

目前光固化复合树脂广泛应用于口腔修复治疗,对其性能的研究也越来越多。复合树脂的耐磨性是决定临床疗效的重要因素。该文就复合树脂磨损机制,磨损研究实验室方法以及增强耐磨性的新型填料等方面作一综述。     

Detection of Bisphenol A in dental wastewater after grinding of dental resin composites

ObjectivesThis study evaluated the release of bisphenol A (BPA) in wastewater after grinding of resin composites and tested three filtration materials.MethodsThree resin composites (Ceram X, Filtek Supreme XTE and Core-X flow) were used. Samples (5 mm × 2 mm, n = 10) were prepared using a metal mold and were polymerized for 20 s according to manufacturers’ instructions. A dental unit was disconnected from wastewater circulation and composite samples were ground under standardized procedures (200,000 rpm; 90 s). Wastewater was collected in glass bottles. Water samples were collected as control by performing the same procedure without grinding resin composite. All samples were stored at 7 °C for 6 months to simulate storage. Then they were analyzed by HPLC–FLD. Three filtration materials (Zeosorb, Katalox Light and Catalytic Carbon) were used for water treatment to remove BPA. BPA-water solutions were prepared; corresponding to the highest amount released by the resin composites. These solutions were analyzed before and after filtration by HPLC–FLD and their efficacy (%) was calculated.ResultsBPA was detected in all composite solutions: Ceram X and Filtek Supreme XTE showed similar findings (p > 0.05) which were significantly higher than the control (p < 0.001) and Core-X flow (p = 0.001). The efficacy of the filtration materials was: Katalox Light (5.09%) < Zeosorb (7.91%) < Catalytic Carbon (99.38%). Only Catalytic Carbon caused a clinically significant reduction of BPA (p < 0.05).SignificanceBPA can be released in wastewater during dental procedures. This release seems to be material dependent. Among the filtration methods tested, Catalytic carbon seems to be effective for BPA reduction in water.     

Miniature specimens for fracture toughness evaluation of dental resin composites

Objective

Millimeter-scale (“miniature”) specimens enable in-situ evaluation of mechanical properties of engineering materials at reduced cost. Here three such specimens for measuring fracture toughness (K_C) are developed and implemented to new dental materials. The latter include concurrent methacrylate-based and new ether-based resin composites designed to reduce polymerization stress and enhance service life in restored teeth.

High performance dental resin composites with hydrolytically stable monomers

Objective

The objectives of this project were to: 1) develop strong and durable dental resin composites by employing new monomers that are hydrolytically stable, and 2) demonstrate that resin composites based on these monomers perform superiorly to the traditional bisphenol A glycidyl dimethacrylate/triethylene glycol dimethacrylate (Bis-GMA/TEGDMA) composites under testing conditions relevant to clinical applications.

Characterization and toxicity evaluation of air-borne particles released by grinding from two dental resin composites in vitro

ObjectiveThe project aims to evaluate whether inhalation of particles released upon grinding of dental composites may pose a health hazard to dentists. The main objective of the study was to characterize the dust from polymer-based dental composites ground with different grain sized burs and investigate particle uptake and the potential cytotoxic effects in human bronchial cells.MethodsPolymerized blocks of two dental composites, Filtek? Z250 and Filtek? Z500 from 3M? ESPE, were ground with super coarse (black) and fine (red) burs inside a glass chamber.Ultrafine airborne dust concentration and particle size distribution was measured real-time during grinding with a scanning mobility particle sizer (SMPS). Filter-collected airborne particles were characterized with dynamic light scattering (DLS) and scanning electron microscopy (SEM).Human bronchial epithelial cells (HBEC-3KT) were exposed to the dusts in dose-effect experiments. Toxicity was measured with lactate dehydrogenase (LDH) assay and cell counting kit-8 (CCK8). Cellular uptake was observed with transmission electron microscopy (TEM).ResultsAirborne ultrafine particles showed that most particles were in the size range 15?35 nm (SMPS). SEM analysis proved that more than 80% of the particles have a minimum Feret diameter less than 1 μm. In solution (DLS), the particles have larger diameters and tend to agglomerate. Cell toxicity (LDH, CCK8) is shown after 48 h and 72 h exposure times and at the highest doses. TEM showed presence of the particles within the cell cytoplasm.SignificanceProlonged and frequent exposure through inhalation may have negative health implications for dentists.     

Conservative restoration with resin composites of a case of amelogenesis imperfecta

Amelogenesis imperfecta (AI) is an inherited enamel dysplasia involving both dentitions with no other systemic effects. The hereditary pattern is autosomal or X-related dominant or recessive. Its prevalence is approximately 1:14,000-1:16,000. It can be classified as hypocalcified, hypoplastic and hypomaturated according to clinical, radiological, histological and hereditary findings. This study presents a case of hypomaturated type AI in a 16-year-old young man that was successfully treated with different types of resin composites. The patient was regularly recalled during the one-year postoperative period. Radiographic and clinical examinations at recall revealed no evidence of complications associated with the restored teeth or their supporting structures.     

A review and current state of autonomic self-healing microcapsules-based dental resin composites

ObjectiveThis study systematically reviews the literature on self-healing microcapsule technology and evaluates the biocompatibility of self-healing microcapsules and the efficiency of crack repair within resin-based dental composites.MethodsAn electronic search was carried out using the following databases: MedLine (PubMed), Embase, the Cochrane Library and Google Scholar. All titles and abstracts of the articles and patents found were analysed and selected according to the eligibility criteria. Only studies published in English were included; the outcomes sought for this review were dental resin composites with self-healing potential. There were no restrictions on the type of self-healing system involved in dental resin composites.ResultsThe search yielded 10 studies and 2 patents involving self-healing approaches to dental resin composites. According to the current literature on self-healing dental resin composites, when a crack or damage occurs to the composite, microcapsules rupture, releasing the healing agent to repair the crack with a self-healing performance ranging from 25% to 80% of the virgin fracture toughness.SignificanceSelf-healing strategies used with resin composite materials have, to date, been bioinspired. So far, self-healing microcapsule systems within dental composites include poly urea-formaldehyde (PUF) or silica microcapsules. The main healing agents used in PUF microcapsules are DCPD monomer and TEGDMA-DHEPT, with other agents also explored. Silica microcapsules use water/polyacid as a healing agent. All self-healing systems have shown promising results for self-repair and crack inhibition, suggesting a prolonged life of dental composite restorations. More investigations and mechanical enhancements should be directed toward self-healing technologies in dental resin composites.     

Cytotoxic effects of dental resin liquids on primary gingival fibroblasts and periodontal ligament cells in vitro

Cytotoxic effects of resin liquids of three in situ relining dental polymers, Alike, Kooliner, and Tokuso Rebase, and their major components, methyl methacrylate (MMA), isobutyl methacrylate (IBMA), and 1,6-hexanediol dimethacrylate (1,6-HDMA) were investigated. The concentrations of major monomers in these resin liquids were determined by high-performance liquid chromatography. Cellular viability of human gingival fibroblasts (GF) and periodontal ligament (PDL) cells were evaluated by the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyltetrazolium bromide assay. Moreover, patterns of cell death were analysed using annexin V/propidium iodide staining with flow cytometry. The results indicated that Alike liquid contained 91.3% MMA, Kooliner liquid contained 94.5% IBMA, and Tokuso Rebase liquid contained 65.8% 1,6-HDMA. All materials examined had cytotoxic effects on GF and PDL cells in dose-dependent manners. Tokuso Rebase liquid appeared to be the most cytotoxic among the various resin liquids examined. The effects of Kooliner and Tokuso Rebase liquids may have resulted from IBMA and 1,6-HDMA, respectively. Furthermore, the majority of treated cells died from necrosis; whereas a small portion of cells died from apoptosis. In conclusion, the results demonstrated that these liquid forms of dental polymers and their major monomers cause cytotoxic reactions. The direct relining procedure that cures these materials in situ should be used cautiously.     

Surface morphology and mechanical properties of new-generation flowable resin composites for dental restoration

Objectives

The purpose of this study was to characterize the surface morphology and the elastic properties of four dental restorative flowable composites currently on the market (Venus Diamond Flow, Vertise Flow, Filtex Supreme XT Flow, Surefil SDR Flow). Additionally, one adhesive system (Adhese One F) and one non-flowable composite (Venus Diamond) have also been characterized as the control materials.

Methods

Surface morphology was studied by both scanning electron and atomic force microscopy, and the elastic modulus and the hardness measured by instrumented indentation. Grain analysis was performed on the microscopic images, and statistical analysis was carried out on the results of the nanoindentation measurements.

Results

It was observed that Vertise, Filtek XT and Surefil SDR exhibit stiffness similar to the non-flowable Venus Diamond, whereas Venus Diamond Flow presents itself as the more compliant flowable composite, with Adhese showing intermediate stiffness. Grain analysis of the images confirmed the general rule that the mechanical properties improve with increasing filler loading, with the notable exception of Vertise Flow that shows modulus and hardness as high as 9.1 ± 0.6 and 0.43 ± 0.03 GPa, respectively, for an estimated loading of only ∼40% by volume.

Significance

Whereas generally flowable composites are confirmed not to possess sufficiently strong mechanical properties for bulk restorations, exceptions can eventually be found upon appropriate laboratory screening, as presently seems to be the case for Vertise Flow. However, real practice in actual restorations and respective clinical evaluation are required for final assessment of the suggested results.