Assessing the estrogenic activity of chemicals present in resin based dental composites and in leachates of commercially available composites using the ERα-CALUX bioassay

ObjectiveThe biocompatibility of resin based dental composites has not yet been fully characterized even though certain monomers used in these composites are synthesized from Bisphenol A (BPA), a well-known estrogenic endocrine disruptor. As a result, they show structural relationship to BPA and can contain it as an impurity. Therefore, the estrogenic activity of 9 monomers, 2 photoinitiators, one photostabilizer and leachates of 4 commercially available composites was determined.MethodsThe ERα-CALUX bioassay was used to determine both agonistic and antagonistic estrogenic activities of the pure compounds (BPA, BisDMA, BisGMA, BisEMA(3), BisEMA(6), BisEMA(10), TEGDMA, TCD-DI-HEA, BADGE, UDMA, HMBP, DMPA, CQ) and the leachates of cured composite disks. The leachates of 4 commercially available composites (Solitaire 2, Ceram.x Spectra ST, G-ænial Posterior and Filtek Supreme XTE) in water and 0.1 M NaOH (pH = 13, ‘worst-case scenario’) were tested for estrogenic activity (pooled leachates from 10 cured composite disks).ResultsAgonistic estrogenic activity was found for the monomer BisDMA, the photostabilizer HMBP and photoinitiator DMPA. All leachates from the 4 tested composites showed significant agonistic estrogenic activity higher than the DMSO control, and the highest activity (potency and efficacy) was found for Solitaire 2, followed by Ceram.x Spectra ST. Furthermore, antagonistic estrogenic activity was found in the leachates from G-ænial Posterior.SignificanceThese results show that significant estrogenic activity was found in all leachates of the cured composite disks, and that this estrogenicity is most likely due to a mixture effect of multiple estrogenic compounds (including BPA, HMBP and DMPA). This indicates that further research into the endocrine activity of all the compounds that are present in these composites (even at low quantities) and their possible mixture effect is warranted to guarantee their safe use.     

Investigating filler morphology and mechanical properties of new low‐shrinkage resin composite types

Summary Three types of low‐shrinkage composites are today commercially available: Ormocers, cationic ring‐opening curing systems and highly filled methacrylate‐based materials, which cure via free‐radical polymerization mechanisms. The aim of this study was to characterize the inorganic fraction of materials belonging to each type and to compare their mechanical properties. Two Ormocers (Admira and an experimental Ormocer V35694), one ring‐opening composite (Filtek Silorane) and five methacrylate‐based composites [Filtek Supreme XT, Tetric EvoCeram, Grandio, Synergy D6 (Coltène‐Whaledent, Langenau, Germany) and an experimental material, V34930] were tested. Inorganic fillers were quantified by thermogravimetric analysis and morphologically characterized by scanning electron microscopy. Dynamic modulus was determined by an impulse excitation technique, static elastic moduli and flexural strength by a three‐point bending method. The results were analyzed using anova tests (P < 0·05) and linear correlations. Grandio, V34930 and V35694 exhibited significantly higher filler mass fractions. Both dynamic and static moduli of Grandio and V34930 were significantly higher than the other materials (P < 0·05), although no significant difference in flexural strength was observed between material type (P > 0·05). From the present findings, it was suggested that V35694 and Filtek Silorane exhibit comparable properties to conventional methacrylate‐based composites, although clinically the cavity type and location must guide material choice. Under high occlusal load, the use of Grandio and V34930 might be favoured. For small cavities, alternative technologies could be preferred as the need for mechanical resistance is lower and the potential for stress generation is greater.     

改良加藤氏厚涂片法在肝吸虫检测中的研究

目的探讨改良加藤氏厚涂片法在肝吸虫检测应用中的优越性。方法针对2009～2011年河源市龙川县疾病预防控制中心体检时疑似肝吸虫病的261例患者,分别对其进行病原学和血清学进行诊断,病原学诊断包括直接涂片法和改良加藤氏厚涂片法,血清学诊断采用酶联免疫吸附试验,并对其检测结果进行比较。结果对于病原学诊断方式,改良加藤氏厚涂片法无论是单次检出率还是总体检出率都优于直接粪便涂片法。酶联免疫吸附试验的检出率在统计意义上与3次改良加藤氏厚涂片法检出率无差异。结论在肝吸虫的病原学诊断中,改良加藤氏厚涂片法检测耗材成本低,针对性强,采样简单,样本用量少,虫卵形态清晰,误检漏检率低,阳性检出率明显提高。一旦检出虫卵,便可确诊,更具有推广意义。     

皮能快愈敷料在深度烧伤创面治疗中的改良应用

目的 探讨皮能快愈敷料对深度烧伤患者的治疗效果.方法 2008年8月至2010年8月我们收治深度烧伤患者22例.患者入院后立即进行创面深度及烧伤严重程度评估,待生命体征稳定,创面水肿高峰期结束后行创面治疗,1期清创手术,行皮能快愈敷料移植术,皮能快愈敷料外加湿性敷料(德湿威);2周后Ⅱ期手术,去除皮能快愈敷料硅胶膜行自身刃厚皮移植.结果 22例深度烧伤创面均愈合,皮能快愈敷料无感染及溶解.皮片移植存活,创面外观满意,供皮区瘢痕增生轻.结论 改良皮能快愈敷料与自体刃厚皮复合修复深度烧伤创面具有较好的临床应用价值.     

Variations in helminth faecal egg counts in Kato-Katz thick smears and their implications in assessing infection status with Schistosoma mansoni

Examination of stool specimens by Kato-Katz (K-K) thick smears is the standard method recommended by the WHO for field diagnosis of intestinal schistosomiasis. However, there is increasing concern that this technique has low diagnostic sensitivity. In 326 study subjects, we compared the diagnostic yield of examining one, three or five Kato-Katz thick smears prepared from one stool specimen using 41.7 mg templates. In a subset of 169 subjects who had no demonstrable Schistosoma mansoni eggs in their first three Kato-Katz thick smears, we assessed the comparative advantage of examining an additional three Kato-Katz thick smears from another stool specimen, taken four weeks later, to that of cumulative yield obtained by examining all five Kato-Katz thick smears derived from the first stool specimen. For all helminth infections, single Kato-Katz thick smear-based prevalence estimates were significantly lower than those obtained from triplet or quintet Kato-Katz thick smears. Prevalence of S. mansoni infection based on single, triplet and quintet Kato-Katz thick smears from one stool specimen were 31.3%, 45.7% and 52.1%, respectively. Prevalence estimate of S. mansoni based on quintet Kato-Katz thick smears from the first day stool specimens was not different from cumulative estimate obtained with two triplet Kato-Katz thick smears from two stool specimens, 52.1% and 52.8%, respectively. In conclusion, either examination of quintet Kato-Katz thick smears from one stool specimen using 41.7 mg template or initial triplet Kato-Katz thick smears from one stool specimen, and if these are negative, followed by examination of additional triplet Kato-Katz thick smears from subsequent day stool specimen can adequately assess individuals for infection status with S. mansoni.     

10例先天性巨痣患儿行手术切除的围术期护理

总结先天性巨痣患儿手术切除治疗的围术期护理经验。10例先天性巨痣患儿,利用刃厚皮片切削法治疗7例,使用扩张器埋植、扩张皮瓣转移切除修复法治疗2例,1例使用刃厚皮片切削法＋扩张器埋植、扩张皮瓣转移切除修复法综合治疗。做好患儿及其家属围术期心理护理,以纠正患儿不良的心理状态、积极配合手术;由于创面面积大、边缘不规整,做好术区备皮;术后3～5 d为渗液出现的高峰期,注意患者渗液量和颜色;观察患儿扩张皮瓣和转移皮瓣的血运情况,监测皮瓣指压反应时间;做好扩张器注水护理,每次生理盐水注入20～40 ml,以不引起患儿疼痛等不适症状为宜;由于患儿的治疗周期长,做好治疗间隔的出院期间的出院治疗。本组患儿均取得了满意的治疗效果。     

老年人股骨粗隆间骨折锁定钢板的MIPPO手术

目的：探讨股骨近端解剖锁定钢板微侵入经皮钢板植入技术（minimally invasive percutaneous plate osteosynthesis, MIPPO）治疗老年人股骨粗隆间骨折。方法2009年1月至2010年2月共收治32例股骨粗隆间骨折患者。男13例,女19例;年龄60-86岁,平均68岁。按Evans分型：Ⅰ型1例,Ⅱ型6例,ⅢA型14例,ⅢB型3例,Ⅳ型8例。32例患者中有高血压病12例、糖尿病8例、脑梗死12例、慢性支气管炎5例。所有患者行股骨近端解剖锁定钢板结合MIPPO技术手术治疗。结果全部患者获得随访,随访时间9-18个月,平均11个月。32例患者手术时间45-80min,平均手术时间（45±16）min;术中出血量为60-110ml,平均（80±10）ml;全部患者围手术期内无1例输血。开始负重时间4-8周,骨折愈合时间8-16周。全部病例都获得骨折愈合,无髋内翻、螺钉穿出或退钉等并发症发生。Harris髋关节经手术治疗后功能评分,优24例、良8例。结论对于老年人股骨粗隆间骨折,股骨近端解剖锁定钢板结合MIPPO技术手术治疗具有创伤小、手术时间短、出血少、操作简便,有利于患者的康复,具有良好的临床应用前景。     

Influence of microcapsule parameters and initiator concentration on the self-healing capacity of resin-based dental composites

ObjectiveFracture is one of the main causes for failure of resin-based composite restorations. To overcome this drawback, self-healing resin-based composites have been designed by incorporation of microcapsules. However, the relationship between their self-healing capacity and microcapsule and resin parameters is still poorly understood. Therefore, the objective of this study was to systematically investigate the effect of initiator concentration (in the resin) and microcapsule size and concentration on the self-healing performance of commercially available flowable resin-based composites.MethodsPoly(urea-formaldehyde) (PUF) microcapsules containing acrylic healing liquid were synthesized in small (33 ± 8 μm), medium (68 ± 21 μm) and large sizes (198 ± 43 μm) and characterized. Subsequently, these microcapsules were incorporated into a conventional flowable resin-based composite (Majesty Flow ES2, Kuraray) at different contents (5–15 wt%) and benzoyl peroxide (BPO) initiator concentrations (0.5–2.0 wt%). Fracture toughness (K_IC) of test specimens was tested using a single edge V-notched beam method. Immediately after complete fracture (K_IC-initial), the two fractured parts were held together for 72 h to allow for healing. Subsequently, fracture toughness of the healed resin-based composites (K_IC-healed) was tested as well.ResultsThe fracture toughness of healed dental composites significantly increased with increasing microcapsule size and concentration (2 wt% BPO, p < 0.05). The highest self-healing efficiencies (up to 76%) were obtained with microcapsules sized 198 ± 43 um.Significancecommercially available resin-based composites can be rendered self-healing most efficiently by incorporation of large microcapsules (198 ± 43 μm). However, long-term tests on fatigue and wear behavior are needed to confirm the clinical efficacy.     

Influence of light-cured luting agents and associated factors on the color of ceramic laminate veneers: A systematic review of in vitro studies

Objective

The luting agent plays a significant role in the appearance of ceramic laminate veneers (CLV), allowing improved/stable shade matching with adjacent teeth. A systematic review was conducted to investigate the influence of light-cured luting agents and color-associated factors aiming to draw guidelines for stable shade matching of CLV. The paper has also given an overview of the compositional characteristics of all luting agents and ceramic systems whose performance was presented herein.