不同术式羟基磷灰石义眼座植入术的比较

目的:观察羟基磷灰石义眼座(HA)植入术不同手术方法的临床效果。方法:根据HA植入时机及包裹方式,共分为7种手术方法,其中方法1～3为HAⅠ期植入,方法4～7为HAⅡ期植入。方法1(n =7)为眼内容剜除术后Ⅰ期植入,自体双层巩膜包裹HA前部;方法2(n =1)为眼内容剜除术后Ⅰ期植入,自体巩膜包裹HA后部;方法3(n =1)为眼球摘除术后Ⅰ期植入,自体巩膜包裹HA前部;方法4(n =2)眼内容剜除术后Ⅱ期植入,萎缩的自体巩膜包裹HA前部;方法5(n =2)眼球摘除术后Ⅱ期植入;方法6(n =3)为眼球摘除术后Ⅱ期植入,异体巩膜包裹整个HA;方法7(n =2)为眼球摘除术后Ⅱ期植入,异体巩膜包裹HA前部。观察7种术式患者的结膜伤口及HA情况。结果:所有18例中,方法1有2例结膜伤口哆开,方法5有1例HA暴露,方法7有1例巩膜溶解,HA暴露,其余14例Ⅰ期愈合。结论:采用不同术式HA植入中,Ⅰ期植入术后并发症轻,HA活动好,手术时机是提高HA植入成功的重要因素。     

羊膜加巩膜前部覆盖防治羟基磷灰石义眼座眶内植入暴露的临床分析

目的:探讨羊膜加前部巩膜覆盖对防治羟基磷灰石(HA)义眼座植入暴露的临床效果。方法:采用羊膜联合自体或异体巩膜为加固物对13例(13眼)行Ⅰ、Ⅱ期HA义眼座植入,随访12～20mo。结果:13例均获得了较好的疗效,未见其他并发症。结论:在行HA义眼座植入时采用羊膜联合前部自体或异体巩膜覆盖加固有利于结膜创口的愈合,预防创口裂开,减少义眼座暴露。     

树脂加强型玻璃离子黏结剂黏结力的实验研究

目的 了解光固化树脂加强型玻璃离子水门汀的剪切强度能否满足临床需要;并比较不同条件下其剪切强度的变化.方法 收集离体前磨牙50颗,随机均分为5组.第1组(对照组):35%磷酸酸蚀30s,冲洗、干燥,涂黏结剂,采用京津釉质黏结剂黏结托槽.第2、4组:35%磷酸酸蚀30s,冲洗,湿润,采用光固化型的Fuji Ortho Lc树脂加强型玻璃离子黏结托槽.第3、5组:不酸蚀,采用光固化型的Fuji Ortho Lc树脂加强型玻璃离子黏结托槽.1、2、3组用电子万能实验机测24h的抗剪切强度,4、5组测30 min的抗剪切强度.并统计牙面上的黏结剂残留量.结果 第2、3、4组的抗剪切强度均能满足临床需要,第5组的抗剪切强度不能满足临床需要,第2组的抗剪切强度与其它各组相比差别有显著性.结论 光固化树脂加强型玻璃离子在酸蚀和免酸蚀后24h,以及酸蚀黏结30min后的剪切强度均能满足临床需要;而免酸蚀黏结30min的抗剪切强度不能满足临床需要;酸蚀后光固化树脂加强型玻璃离子的剪切强度明显增强.     

Influence of Silica Fume on High-Calcium Fly Ash Expansion during Hydration

The purpose of this work was to study the possibility of neutralizing high-calcium fly ash expansion during hydration. The object of the study was the fly ash of Berezovskaya GRES, which is capable of independent setting and hardening. The test in the Le Chatelier molds showed that the divergence of indicator arms was 90–100 mm 1 day after mixing with water. The expansion and cracking of the fly ash could be completely prevented by silica fume addition in an amount of 42.9% by weight of the fly ash. At the same time, the compressive strength of specimens from the fly ash–sand paste in a ratio of 1:5 at the age of 28 days was 1.47 MPa. The isothermal heat release at a temperature of 20 °C for 10 days reached 500 kJ/kg. XRF and DTA results showed that free lime in the fly ash was completely hydrated in 11 days and gave the greatest expansion in the absence of silica fume. The presence of silica fume made the lime hydration incomplete and decreased the expansion. Unslaked free lime remained in the system. Exothermic data showed that silica fume inhibited CaO hydration from the reaction start.     

不同粘结剂对瓷-牙本质粘结剪切强度的研究

目的：观察比较不同树脂粘结剂对IPS Empress 2全瓷基底粘结剪切强度的效果。方法：选择无龋坏的人磨牙24个,随机分为4组,每组6个。第1组用RelyX Veneer进行粘结。第2组用RelyX unicem进行粘结。第3组用RelyX ARC进行粘结。第4组用Variolink 2进行粘结。所有样本在37°C蒸馏水中储存24h后,进行测试,记录剪切强度值,用SPSS11.0对结果进行单因素方差分析,并在光学显微镜下观察粘结破坏情况。结果：RelyX Veneer、RelyX ARC、Variolink 2的剪切强度显著高于RelyX unicem的剪切强度（P〈0.05）,破坏界面多发生在牙本质与粘结剂之间。结论：RelyX Veneer、RelyX ARC、Variolink 2都可以用于IPS Empress 2全瓷系统的粘结。     

血液环境下Biodentine与MTA的颜色稳定性研究

目的 比较牙体牙髓治疗中常用的骨水泥材料Biodentine与三氧化矿物凝聚体(mineral trioxide ag-gregrate,MTA)在与血液接触条件下的颜色稳定性,并探讨其可能的变色原因.方法 制备直径5 mm、高3 mm的Biodentine和MTA圆盘,将每种材料的24个圆盘随机分配到去离子水组和脱纤...     

Analysis of Carbonation Behavior of Cracked Concrete

The crack and carbonation of concrete pose a great challenge to its durability. Therefore, this paper studies the effect of cracks on the carbonation depth of cement paste under different factors. The relationship between carbonation and cracks was determined, and the carbonation mechanism of cement paste with cracks was clarified. The results show that a small water–binder ratio can effectively inhibit the carbonation process. The bidirectional carbonation enlarged the carbonation area around the crack. Within 21 days of the carbonation, the carbonation depth increased with carbonation time, and the Ca(OH)₂ on the surface of the specimen was sufficient, allowing for a convenient chemical reaction with CO₂. The influence of crack width on the carbonation process at the crack was greater than the influence of the crack depth. Carbonation influenced the hydration of cement-based materials, altering the types and quantities of hydration products. In conclusion, accurately predicting the regularity of carbonation in cracked structures is critical for improving the durability of concrete.     

Supercritical CO2 Curing of Resource-Recycling Secondary Cement Products Containing Concrete Sludge Waste as Main Materials

This study aims to develop highly durable, mineral carbonation-based, resource-recycling, secondary cement products based on supercritical carbon dioxide (CO₂) curing as part of carbon capture utilization technology that permanently fixes captured CO₂. To investigate the basic characteristics of secondary cement products containing concrete sludge waste (CSW) as the main materials after supercritical CO₂ curing, the compressive strengths of the paste and mortar (fabricated by using CSW as the main binder), ordinary Portland cement, blast furnace slag powder, and fly ash as admixtures were evaluated to derive the optimal mixture for secondary products. The carbonation curing method that can promote the surface densification (intensive CaCO₃ formation) of the hardened body within a short period of time using supercritical CO₂ curing was defined as “Lean Carbonation”. The optimal curing conditions were derived by evaluating the compressive strength and durability improvement effects of applying Lean Carbonation to secondary product specimens. As a result of the experiment, for specimens subjected to Lean Carbonation, compressive strength increased by up to 12%, and the carbonation penetration resistance also increased by more than 50%. The optimal conditions for Lean Carbonation used to improve compressive strength and durability were found to be 35 °C, 80 bar, and 1 min.     

Evaluating the Effect of Tideglusib-Loaded Bioactive Glass Nanoparticles as a Potential Dentine Regenerative Material

Dental pulp treatment is the least intrusive procedure currently available for preserving the vitality of the pulp. Several studies are underway to improve the bioactivity of pulp capping materials. Tideglusib isa potent anti-inflammatory, antioxidant, and a regenerative drug developed against Alzheimer’s disease and has been shown to be effective in the treatment of dental cavities. However, its bioactive properties encapsulated within the nanoparticles as a component of pulp capping material are largely unknown. In this study, tideglusib-loaded bioactive glass nanoparticles were synthesized (tideglusib-BgNPs) and mixed at various concentrations into the calcium silicate cement to testits physiomechanical and bioactivitiescompared with biodentine (control). The calcium silicate cement with 10wgt% tideglusib-BgNPs showed comparable physiomechanical properties to that of biodentine. Additionally, the assessment of cytotoxicity and bioactivity (cell proliferation, wound healing, and cell migration assays) showed increased bioactivity in terms of better wound healing, increased proliferation, and better migration of human dental pulp stem cells than biodentine. These findings suggest new opportunities to use tideglusib-BgNPs in pulp therapy.     

Thermodynamic Modeling Study of Carbonation of Portland Cement

The assessment of the extent of carbonation and related phase changes is important for the evaluation of the durability aspects of concrete. The phase assemblage of Portland cements with different clinker compositions is evaluated using thermodynamic calculations. Four different compositions of cements, as specified by ASTM cements types I to IV, are considered in this study. Calcite, zeolites, and gypsum were identified as carbonation products. CO₂ content required for full carbonation had a direct relationship with the initial volume of phases. The CO₂ required for portlandite determined the initiation of carbonation of C-S-H. A continual decrease in the pH of pore solution and a decrease in Ca/Si is observed with the carbonation of C-S-H. Type II cement exhibited rapid carbonation at relatively less CO₂for full carbonation, while type III required more CO₂ to carbonate to the same level as other types of cement. The modeling of carbonation of different Portland cements provided insights into the quantity of CO₂ required to destabilize different hydrated products into respective carbonated phases.