Comparative radiopacity of bone graft materials

The aim of this study was to investigate the radiopacity of bone graft materials (BGMs) in comparison with bovine mandibular cortical bone and human dentine. Eight samples of each material (8 mm in diameter and 3 mm in thickness) were prepared from Dexabone^® (DB), Bio - Oss^® (BO), 4BONE SBS (4B), KASIOS^® TCP (KA), S.C. PONETI (PO), and Apatite-Wollastonite (AW). The optical densities of each material, along with one tooth section (human canine tooth 1 mm slice), bovine mandibular cortical bone (BC) samples, and an aluminum step wedge, were measured from radiographic images using a transmission densitometer. The data were analyzed by nonparametric one-way ANOVA (Kruskal-Wallis) and Duncan’s multiple range tests for post hoc comparison (α = 0.05). BC and AW had statistically lower optical density values than BO, 4B and human dentine (p < 0.05). Among BGMs, AW (3.681 ± 0.409 mm eq Al) had the highest radiopacity values whereas BO (1.925 ± 0.176 mm eq Al) had the lowest one. The radiopacity values of DB and KA did not reveal a statistically significant difference when compared with other materials (p > 0.05). The radiopacity of all BGMs investigated seemed to be too low to be detected radiographically when placed in the mandibular cortical bone.     

Effects of calcium phosphate ceramic bone graft materials on permanent teeth eruption in beagles.

OBJECTIVE: The aim of this study was to evaluate the use of calcium phosphate ceramic (CPC) materials as a potential alternative to autogenous secondary alveolar bone grafting in cleft lip and palate patients who are in mixed dentition. SAMPLE: Four 12-week-old beagles and one 15-week-old beagle were used as subjects. INTERVENTIONS: In each experimental beagle, the third and fourth deciduous premolars were extracted. The sockets were filled with four different CPC materials and sutured. MAIN OUTCOME MEASURES The beagles were fed a soft diet for the following 8 weeks and then sacrificed for clinical, radiological, histological, transmission electron microscope (TEM), and infrared (IR) absorption analysis. RESULTS: All four experimental graft materials allowed normal development and eruption of permanent premolars. In histological sections, small particles of biphasic calcium phosphate (BCP) and carbonate apatite (CO(3)-AP) were resorbed, and large particulate forms served as bone frames in cortical bones. Polymer coated with carbonate apatite (Poly/CO(3)-AP) did not cause inflammation but was pushed away to the soft tissue by erupting teeth. Alginate coated with carbonate apatite (alginate/CO(3)-AP) caused a severe inflammatory reaction to the point of destroying a part of the dental follicle and cortical bone. In TEM, resorption activity by phagocytic cells was observed only in CO(3)-AP. Direct bonding of CO(3)-AP to the bone was observed as the electron-dense interface between bone and CO(3)-AP.Conclusion: BCP and CO(3)-AP proved to be suitable as alveolar bone graft materials in areas where tooth eruption occurs. Of the four materials tested, CO(3)-AP produced the best results.     

人体骨组织替代材料-骨界面形态和元素分析

采用新合成的人体现有组织替代材料羟基聚磷酸钙钠和羟基磷灰石、生物玻璃陶瓷、钛合金分别植入９只家犬下颌骨拔牙创中，入术后半月、月和３月用Ｘ线检查、扫描电镜和Ｘ线能谱等方法来考察这些材料对骨愈合过程的影响。结果表明。这４种材料均与骨界面间形成骨性结合，尤以羟基聚酸钙钠早期易形成骨性结合界面。在实验早期，材料一骨界面的钙、磷含量低，面硫、硅含量高。随时间延长，骨界面的钙、磷含量逐渐增高，而硫、硅含量量农     

Comparative in vitro evaluation of color and color stability of composite and ceramic ionomer materials for esthetic repair of teeth

Comparative colorimetric evaluation of shades and translucency of different samples, fabricated from Filtec Z-250, Unirest, Dyract AP and Vitremer, shows, that differences in their compositions and industrial technologies result to great differences between the shades of the same number of Vita Shade Guide. The less color stability after long term action by foods media to the samples was found for the glass ionomer cement. The best color stability was found for composites, partially, for Unirest. All of these, let us conclude, that the main changes, not only in shades, but in translucency of materials, as a result the action of model media, take place at the early periods (the first month). Usually, the most main changes in restorative materials take place in this period of beginning and connect with the end of setting processes and achieving the balances between water absorption and solubility.     

R-curve behavior of dental ceramic materials

Some technical ceramics exhibit the R-curve effect, i.e., an increasing fracture resistance with crack extension which is a desirable material property because more energy is necessary to propagate a microscopic crack. The objective of this study was to prove whether dental ceramic materials exhibit R-curve behavior. Nine dental ceramics were examined by the indentation-strength method. It was found that all of the tested ceramic materials exhibit a rising R-curve with crack extension. The R-curve behavior was more pronounced for the high-strength materials In-Ceram Alumina, monolithic alumina, and especially Empress 2. We conclude from our results that the mechanical behavior of a dental ceramic material can be judged more comprehensively, if the R-curve of the respective material is known.     

四种骨组织替代材料—骨界面区细胞IGF—ImRNA表达水平原位杂…

采用鼠有内植入４种人体骨组织替代材料的动物实验，经组织核酸分子原位杂交技术（ＩＳＨＨ），研究了４个时期材料对界面区细胞胰岛素生长因子－Ｉ（ＩＧＦ－Ｉ）ｍＲＮＡ表达水平的影响。结果发现材料能够影响界面区细胞的ＩＧＦ－ＩｍＲＮＡ的表达水平，它的表达增强与界面区细胞增殖、基质产生和新骨形成有关。并且ＩＧＦ－ＩｍＲＮＡ的检测有助于界面区细胞功能状态的判定。     

四种全瓷修复材料的透光度比较

目的采用全瓷试样,对四种全瓷材料进行透光度测试,为全瓷修复的临床应用提供参考依据。方法选择四种全瓷材料：IPS Empress 2、VITA In-Ceram AIumina、VITA In-Ceram Zirconia及CerconZircinia。每种材料各做出厚为（0.5±0.05）mm,直径为14mm之试样8片（n=8）,使用色度计进行试样之透光度测试。结果透光度由高至低依序为Em2 0.5mm（0.78）、InA 0.5mm（0.94）、InZ 0.5mm（1.0）、Cer 0.5mm（1.0）。结论 IPS Empress 2为透光性最佳,适用于高度美观需求之前牙。VITA In-Ceram Alumina透光度偏低,而VITA In-Ceram Zirconia、Cercon均不透光,此二种烤瓷材料临床上宜应用于美观需求不高之后牙区。     

瓷修复技术的临床应用Ⅶ.牙科全瓷材料的分类与应用

按照国际ISO6872牙科陶瓷标准,牙科陶瓷分为两种类型,Ⅰ型是以粉体形式构成的材料,其以用途再细分为8个类别,并有国际ISO6872推荐的颜色标识以鉴别瓷粉类别,见表1.Ⅱ型是以其他形式构成的材料,可再细分为2个类别:第1类用于制作冠、贴面、嵌体和高嵌体的支持结构,第2类直接用于制作贴面、嵌体和高嵌体.     

不同核材料与二氧化锆陶瓷树脂粘接耐久性的研究

目的 研究不同类型核材料与二氧化锆陶瓷树脂间的粘接强度及耐久性。方法 二氧化锆陶瓷盘经研磨后通过2种自粘接型树脂水门汀（Clearfil SA Luting和RelyX U100）与不同核材料包括流动型复合树脂核材料、充填型复合树脂、钴铬合金以及牙本质进行粘接,组成个8实验组。每个实验组再分成2个亚组,分别接受0、10 000次冷热循环后进行剪切粘接强度测试。结果 核材料、树脂水门汀材料及老化条件均会对粘接强度产生明显影响（P<0.001）。冷热循环后,只有Clearfil SA Luting与钴铬合金的粘接强度没有明显降低（P>0.05）,并高于其余各核材料组（P<0.05）;Clearfil SA Luting与钴铬合金、流动型复合树脂核材料及充填型复合树脂间的粘接强度均明显高于RelyX U100相对应的粘接强度（P<0.05）,而Clearfil SA Luting和RelyX U100与牙本质间的粘接强度的差异无统计学意义（P>0.05）。结论 不同类型核材料和树脂水门汀材料能够对二氧化锆陶瓷树脂粘接耐久性产生明显影响。     

全瓷材料的临床应用进展

全瓷材料化学性能稳定，生物性能优良，表面光泽度高，能恢复牙体组织的天然色彩，具有极佳的审美性。本文就全瓷材料在口腔修复中包括嵌体、贴面、全冠、固定桥、桩核及种植义齿修复等方面的临床应用，做了简要介绍，认为全瓷材料在口腔修复临床应用中具有极广阔的前景。