Magnesium modification of a calcium phosphate cement alters bone marrow stromal cell behavior via an integrin-mediated mechanism

The chemical composition, structure and surface characteristics of biomaterials/scaffold can affect the adsorption of proteins, and this in turn influences the subsequent cellular response and tissue regeneration. With magnesium/calcium phosphate cements (MCPC) as model, the effects of magnesium (Mg) on the initial adhesion and osteogenic differentiation of bone marrow stromal cells (BMSCs) as well as the underlying mechanism were investigated. A series of MCPCs with different magnesium phosphate cement (MPC) content (0∼20%) in calcium phosphate cement (CPC) were synthesized. MCPCs with moderate proportion of MPC (5% and 10%, referred to as 5MCPC and 10MCPC) were found to effectively modulate the orientation of the adsorbed fibronectin (Fn) to exhibit enhanced receptor binding affinity, and to up-regulate integrin α5β1 expression of BMSCs, especially for 5MCPC. As a result, the attachment, morphology, focal adhesion formation, actin filaments assembly and osteogenic differentiation of BMSCs on 5MCPC were strongly enhanced. Further in vivo experiments confirmed that 5MCPC induced promoted osteogenesis in comparison to ot her CPC/MCPCs. Our results also suggested that the Mg on the underlying substrates but not the dissolved Mg ions was the main contributor to the above positive effects. Based on these results, it can be inferred that the specific interaction of Fn and integrin α5β1 had predominant effect on the MCPC-induced enhanced cellular response of BMSCs. These results provide a new strategy to regulate BMSCs adhesion and osteogenic differentiation by adjusting the Mg/Ca content and distribution in CPC, guiding the development of osteoinductive scaffolds for bone tissue regeneration.     

Long-term follow-up of camouflage effects following resin infiltration of post orthodontic white-spot lesions in vivo

Objectives:To reassess the long-term camouflage effects of resin infiltration (Icon, DMG, Hamburg, Germany) of white spot lesions (WSL) and sound adjacent enamel (SAE) achieved in a previous trial. The null hypothesis was tested that there were no significantly different CIE-L*a*b*-ΔE-values between WSL and SAE areas of assessment after at least 24 months (T24) compared to those at baseline (T0).Materials and Methods:Of twenty subjects who received previous resin infiltration treatment of n_teeth = 111 nonrestored, noncavitated postorthodontic WSL after multibracket treatment during a randomized controlled trial and were contacted 20 months after baseline, eight subjects (trial teeth n_teeth = 40; m/f ratio 1/7; age range (mean; SD) 12–17 [15.25; 2.12] years); response rate: 40%) were available for follow-up after at least 24 months (T24). CIE-L*a*b* differences between summarized color and lightness values (ΔE_WSL/SAE) of WSL and SAE were assessed using a spectrophotometer and compared to baseline data assessed prior to infiltration (T0), and those after 6 (T6), and 12 (T12) months using paired t tests at a significance level of α = 5%.Results:T24 assessments were performed after a mean 33.86 (SD: 8.64; Min: 24; Max: 45) months following T0. Mean (SD) ΔE_WSL/SAE units of available teeth were 8.76 (5.33) at baseline; 5.5 (2.75) at T6; 5.2 (2.41) at T12; and 5.57 (2.6) at T24. Comparisons of T6, T12, and T24 with T0 yielded highly significant differences, whereas T6–T24 and T12–T24 differences were found to be not significant.Conclusions:Assimilation of infiltrated WSL to the color of adjacent enamel by resin infiltration is considered to be suitable for the long-term improvement in the esthetic appearance of postorthodontic WSL.     

自酸蚀封闭剂与玻璃离子联合用于托槽粘结的临床观察

目的：评价自酸蚀粘结剂与树脂加强型玻璃离子联合用于正畸托槽粘结的临床使用效果。方法：随机选择50名患者，采用自身对照的方法进行为期12个月的临床观察。385个托槽用自酸蚀封闭剂（3MESEP）和光固化树脂加强型玻璃离子水门汀（FUJI ORTHO LC）粘结，390个托槽用京津釉质粘结剂粘结。观察托槽脱落的时间和脱落后粘结剂在牙面上的残留量，计算托槽脱落率和粘结材料残留指教。结果：光固化树脂加强型玻璃离子水门汀和自酸蚀封闭剂粘结的托槽脱落率为10．1％；京津釉质粘结剂粘结的托槽脱落率为9．0％，两者差异没有统计学意义（P〉0．05）。两种材料粘结的托槽脱落后，牙釉质上的粘结材料残留指教差异无显著统计学意义（P〉0．05）。结论：自酸蚀封闭剂和树脂加强型玻璃离子所构成的粘结技术粘结正畸托槽的粘结强度，可以满足正畸治疗的需要，在临床上有广阔的应用前景。     

抗生素骨水泥棒治疗交锁钉术后髓内感染

目的 评价抗生素骨水泥棒治疗髓内钉术后髓腔感染的手术技术和初期临床效果。方法 回顾19例髓内感染患者的情况，分别给予拔除交锁钉、窦道切除、扩髓并给予抗生素骨水泥棒填塞治疗。结果 所有患者均获得随访，平均随访时间16个月，髓内感染均得到控制，窦道创面愈合。11例骨折已愈合，6例患者部分愈合，2例未愈。结论 抗生素骨水泥棒治疗交锁钉术后的髓腔感染操作简单方便，相对经济，是一种较有效的治疗方法。     

Estenia瓷树脂复合体制作冠桥的强度测试

目的:探讨Estenia瓷树脂复合体的强度,并与其他几种树脂材料进行比较,为临床选择冠桥树脂材料提供参考。方法:采用Estenia瓷树脂复合体体外模拟下颌第一磨牙单冠和第一磨牙缺失3个单位固定桥的形态,测试单冠的抗压强度和固定桥的抗弯强度,并与Artglass、Solidex、Targis3种树脂材料在相同实验方法下测试得到的结果作比较。结果:Estenia瓷树脂单冠的折裂最大载荷均值为600.20N,Estenia瓷树脂桥的折裂最大载荷均值为302.53N。结论:Estenia瓷树脂复合体的强度高于Artglass﹑Solidex和Targis树脂复合体。     

大孔树脂在三七叶皂苷脱色中的应用研究

目的:解决三七叶总皂苷提取中的脱色工艺技术。方法:组合大孔树脂法。结果:应用组合大孔吸附树脂,在碱性条件下多级脱色,较好地解决了三七叶总皂苷脱色困难,并实施了大规模产业化。     

用于牙科复合树脂的具有固位力外形的无机填料的研究

本文介绍了一类微细的复合式无机填料。由于具有特殊的表面结构，这类填料与复合树脂中的树脂基质之间有良好的结合力，因此称之为“具有固位力外形的无机填料”。用此类填料配制的试验性复合树脂，不仅其磨耗性能有明显的改善，而且其它机械性能也有不同程度的提高。     

医用磷酸钙骨水泥的制备及性能的实验研究

探索了磷酸四钙（Ca4（PO4）2O，TTCP）的制备，并合成了磷酸钙骨水泥（CPC），对CPC固化时间、引起浸泡液pH值的变化、抗压强度、产物物相组成及微观结构进行了研究。结果表明：在真空条件下、1500℃下煅烧6h可制得TTCP，并含有少量CaO。CPC初凝时间为4min、终凝时间为15min，浸泡1d和7d后的抗压强度分别为20MPa和35MPa，浸泡液的pH值在6．4～8．9之间变化，这些性能均符合临床用CPC的性能要求。CPC水化产物为片状或针状羟基磷灰石（Ca5（PO4）3OH，HA），相互交错呈连续分布的网状结构，这种结构有利于材料强度的提高。实验研制的CPC材料可用于骨缺损的修复治疗。     

牙龈成纤维细胞与牙周韧带细胞在二种玻璃离子水门汀上附着及增？…

目的 比较人类牙龈成纤维细胞（ＨＧＦ）与牙周韧带细胞（ＰＤＬＣ）在两种玻璃离子水门汀（ＧＩＣ）上的附着及增殖情况。方法 利用体外细胞培养技术及＾３Ｈ－ＴｄＲ掺入法检测ＨＧＦ及ＰＤＬＣ在两种ＧＩＣ上的附着及ＤＮＡ合成。结果 ＨＧＦ与ＰＤＬＣ在培养板上的附着及ＤＮＡ合成差异无显著性（Ｐ〉０．０５）,但ＨＧＦ在ＧＩＣ上的附着及ＤＮＡ合成明显强于ＰＤＬＣ（Ｐ〈０．０５）。结论 Ｋｅｔａｃ Ｆｉｌ和Ｆｕｊｉ     

酶法合成L—丝氨酸及反应液中氨基酸的分离

含ｇｌｙＡ的基因工程菌所表达的ＳＨＭＴ可催化甲醛和甘氨酸特异地合成Ｌ－丝氨酸。对酶法合成的部分条件进行了优化,并根据甲醛滴定的原理,确定了通过检测ｐＨ变化控制甲醛流加速度的方案,最终的反应液中Ｌ－丝氨酸浓度达０．２ｍｏｌ／Ｌ。反应结束后的酶反应液中同时含有甘氨酸和丝氨酸,利用国产７１７树脂获得较为理想的分离效果,丝氨酸的收率达７７％,高效液相分析表明其中不含甘氨酸等杂质。