The effect of calcium ion concentration on the bone response to oxidized titanium implants

Aim: To investigate the effect of calcium concentration on the bone tissue response to Ca‐incorporated titanium implants Materials and methods: Two titanium surfaces containing 4.2% and 6.6% calcium were prepared using the micro‐arc oxidation process. The implants were inserted in the tibia of nine New Zealand White rabbits. After 6 weeks of healing, the bone response to the implants was quantitatively compared by biomechanical and histomorphometrical measurements. Results: Ca 4.2% and Ca 6.6% containing implants revealed no distinctive differences in their qualitative surface chemistry; chemical bonding state of Ca in titanium oxide was mainly calcium titanates. No significant differences were observed between two implants in peak removal torque and shear strength comparisons (P>0.05). Histomorphometrical analyses presented no significant differences in bone–metal contact, bone area and newly formed bone measurements between two implants (P>0.05). Conclusions: From biomechanical and histomorphometrical measurements, the two calcium concentrations in this study did not differ significantly with respect to their influence on the bone tissue response. This similar bone response in rabbit tibiae may be explained by the similarity of the qualitative Ca chemistry in titanium surfaces.     

Surgical management of recurrent squamoid eccrine ductal carcinoma of the scalp

Squamoid eccrine ductal carcinoma (SEDC) is an exceedingly rare tumor that shows both squamous differentiation and adnexal ductal differentiation. As our review of the literature revealed, only a total of 7 cases were reported to date. We report an additional case of SEDC occurring on the scalp of a 53-year-old man. Despite complete excision by conventional technique with clear margin, the lesion recurred within a 3-month period, with regional lymph node metastasis. The tumor was completely removed, and the large scalp defect was reconstructed by using scalp rotation flap. We present a case of recurrent SEDC on the scalp, and we surgically resected this tumor. In addition, the large scalp defect was reconstructed successfully with scalp flap, and no recurrence has been observed in the patient's postoperative follow-ups.     

Accuracy and validity of stitching sectional cone beam computed tomographic images

To determine whether three-dimensionally reconstructed images of skulls created by stitching multiple cone beam computed tomographic (CBCT) images are as accurate as single images obtained using multidetector computed tomography (MDCT), 10 skull models were scanned using an optical three-dimensional scanner, MDCT, and CBCT. Cone beam CT images at 3 different levels of the skull were manually superimposed and stitched. The reconstructed CBCT images at each level were aligned and fused using computer software and then compared to the nominal reference image obtained from the optical three-dimensional scanner by determining positional errors. The reconstructed MDCT images were also compared, and the differences in the mean errors for the 3 image types compared with the nominal reference image data were evaluated. There were no significant differences between the MDCT images and the manually merged CBCT images (Wilcoxon signed rank test, P = 0.017). In contrast, there were significant differences between the MDCT images and the software-aligned CBCT images (P = 0.005). Manual stitching of CBCT sectional images at different levels can provide accurate anatomic details of the oral and maxillofacial regions.     

葡聚糖包裹的超顺磁性Fe3O4纳米颗粒用于MRI造影剂的研究

目的探讨葡聚糖包裹的超顺磁性Fe3O4纳米颗粒（dextran-coated superparamagnetic iron oxides nanoparticles,dextran／SPIONP）作为间质注射的MRI造影剂的可行性。方法应用界面共沉淀法,制备dex—tran／SPIONP,用透射电镜、能谱分析、X射线衍射、红外光谱测试、热重分析等方法对dextran／SPIONP的大小、磁性能等进行表征,并研究葡聚糖对SHONP的影响。然后,将dextran／SPIONP稀释成不同剂量,兔舌粘膜下间质注射后的不同时间段,切取前哨淋巴结,行核磁共振波谱分析,确定dextrart／SPIONP的最适剂量和最佳检测时间。结果dextran／SPIONP的平均直径为6～9nm,其表征与经典的共沉淀法制备的颗粒一致,具有超顺磁性,葡聚糖是影响SPIONP饱和磁化强度的主要因素。dextran／SPIONP用于间质注射的最适剂量为含铁量20μmol,最佳检测时间为注射后2Ah。结论用界面共沉淀法制备的dextran／SPIONP是一种适用于间质注射的MRI造影剂。     

壳聚糖基温敏水凝胶对牙周膜成纤维细胞相容性的影响

目的:体外评价壳聚糖季铵盐/甘油磷酸(CS-HTCC/GP)温敏水凝胶的细胞相容性.方法:体外培养人牙周膜成纤维细胞(HPDLCs),采用四甲基偶氮唑盐(MTT)法测定不同浓度的CS-HTCC/GP温敏凝胶浸提液对1、3、5d细胞增殖和碱性磷酸酶(ALP)活性的影响.采用扫描电镜和透射电镜观察对细胞超微结构的影响.采用SSPS13.0软件包对数据进行统计学分析.结果:免疫组化显示,培养的细胞波形丝蛋白染色阳性,角蛋白染色阴性,证明体外原代培养细胞及传代细胞均为中胚层组织来源,且无上皮来源细胞混杂.不同浓度的CS-HTCC/GP温敏水凝胶浸提液均有促进HPDLCs增殖的作用,在第3天和第5天,差异有高度显著性(P＜0.001).各组均可提高ALP活性.第2组和第3组在第5天与第1天ALP表达的提高有高度显著差异(P＜0.001).扫描电镜和透射电镜观察水凝胶浸提液对HPDLCs的超微结构无影响.结论:CS-HTCC/GP温敏水凝胶具有良好的细胞相容性,具有用于牙周局部药物释放系统载体及组织工程支架的潜力.     

垂直生长型安氏Ⅱ类1分类拔牙病例矫治前后硬组织的改变

目的研究垂直生长型安氏Ⅱ类1分类青少年与成人硬组织在矫治前后的变化,以期为正畸临床治疗方案的制定和治疗方法提供参考。方法选择38例垂直生长型安氏Ⅱ类1分类拔牙病例,在矫治前后拍摄X线头颅侧位片,对39个硬组织测量指标进行测量,并对青少年与成人矫治前后的变化量进行比较。结果研究对象矫治后ANB角、NA-PA、U1-FH、U1-NA、U1-Ptm、Spr-Ptm、Id-Go等青少年组与成人组的变化差异有统计学意义;Pog-Go、Cd-Go、S-Go、N-Me等都分别有所增加;与青少年组的OP-FH在正畸治疗后的减小相比较,成人组的OP-FH有所增加,成人组的平面发生了顺时针旋转。结论青少年在正畸治疗中表达更多的骨效应,即青少年通过正畸治疗能够更大程度地改善其Ⅱ类骨面型,更有利于其侧貌美观的改善;青少年上颌磨牙的伸长量基本是在有益的范围内,结合下颌升支等后面高的发育,能够使下颌平面、平面发生逆时针旋转,这对于垂直生长型Ⅱ类1分类病例的正畸治疗和面型改善以及治疗效果的稳定是有利的,同时也提示了垂直生长型Ⅱ类1分类错畸形的正畸治疗最佳时间为生长发育时期。     

初学者应用两种镍钛机动器械预备树脂弯曲根管的效果比较

目的 比较初学者应用两种机用镍钛器械Protaper和Her0642预备树脂弯曲根管的效果.方法 选取仿制单弯树脂根管32个,15名初学者分别用两种机用镍钛系统Protaper和Her0642进行根管预备,2个仿制单弯树脂根管为阴性对照.分别从推出根尖碎屑量、根尖偏移量及根管弯曲度变化等方面评价两种器械系统的根管预备效果.所有数据均采用SPSS 13.0软件包进行统计学分析.结果 Protaper组预备前后根管弯曲度平均减小6.77°,Hero642组减小5.480°,Protaper组减小根管弯曲度较Hero642组明显.Protaper组成形后的根管宽度均值均大于Hero642组,且根管口、根中1/3成形后的根管宽度差异有统计学意义(P<0.05).此外,根管预备过程中Protaper器械折断3支,Hero642器械折断1支.结论 对于初次使用机用镍钛器械的操作者,尽管Protaper具有良好根管成形的优点,但Hero642系统操作技术简单容易掌握、高效、安全,更适合初学者在临床上使用.     

黄芩苷和牛血清白蛋白双缓释制剂的制备及释药性能检测

目的:将黄芩苷和牛血清白蛋白(bovine serum albumin,BSA)载入壳聚糖温敏凝胶,构建双缓释体系,检测凝胶对药物的体外释放情况。方法:采用乳化缩聚法制备黄芩苷-明胶微球(gelatin microspheres,GMS);用不同配比的壳聚糖溶液和β-甘油磷酸钠(β-glycerophosphate,β-GP)溶液制备壳聚糖温敏凝胶,观察在37℃的成胶情况,选择最佳配比;在此基础上,将不同浓度的黄芩苷-GMS与BSA共混于壳聚糖凝胶溶液,测定载药后的成胶情况及黄芩苷和BSA的体外释放情况。结果:成功制备了黄芩苷-GMS,载药率5.62%,包封率72.05%;1.8%壳聚糖溶液与9%的β-GP混合10min后可获得状态良好的凝胶;加载两种药物后的凝胶溶液相转变时间未发生改变;30d时低浓度组累积释放了63.79%,两个较高浓度组分别释放了74.86%、77.63%。结论:壳聚糖温敏凝胶可以同时负载黄芩苷-GMS和BSA两种药物,在室温下呈溶液状态,37℃下经过10min可转变成半固体凝胶,在体外释药可达30d。黄芩苷和牛血清白蛋白双缓释制剂的制备和释药性能检测为牙周组织修复再生药物的研制提供了基础。