牙本质牙髓复合体的形成研究(二)牙本质牙髓复合体的在体形成研究

牙本质牙髓复合体在体形成研究包括牙齿发育完成后在各种因素下形成的第三期牙本质和成牙组织、细胞在口腔以外部位形成牙齿样结构两方面。一些细胞外基质分子和生长因子形成的网络调控在其形成中发挥关键性作用。对这些分子机理的研究将为临床牙髓病的生物保髓治疗和牙髓、牙齿再生替代治疗奠定了基础。     

纯钛表面快速沉积羟基磷灰石涂层的实验研究

目的探讨在纯钛种植体表面快速沉积羟基磷灰石涂层的新方法。方法20片纯钛片均分为A、B两组。A组用H2SO54与HCI混合液酸蚀；B组用H2SO4与HCI混合液酸蚀，再用5mol／L NaOH溶液60℃处理24h后，600℃热处理1h。然后两组试件同时置于仿生液A液和B液中各1天。场发射扫描电子显微镜观察分析涂层的形貌。结果两组试件表面均可沉积致密的羟基磷灰石涂层，涂层由1—3μm的小球组成。X射线衍射分析证实其为碳酸化的羟基磷灰石。结论在纯钛表面可以快速沉积碳酸化的羟基磷灰石。     

下颌骨溶骨症1例报告及文献复习

溶骨症又称Gorham综合征，临床罕见，其病因及发病机制尚不清楚，以自发性进行性骨溶解吸收为主要临床表现。溶骨症可发生于任何年龄，特别好发于5-25岁，无明显性别差异，可发生于单一骨骼，也可跨过关节，侵犯多个骨骼。目前认为，早期彻底切除可有效阻止病变进展。作者报告1例，并结合相关文献，对该病的临床特点，好发部位，诊断与鉴别诊断及治疗方法进行讨论。     

Performance of Five Commercially Available Tooth Color-Measuring Devices

PURPOSE: Visual tooth color assessment is neither accurate nor precise due to various subjective and objective factors. As newly developed tooth color-measuring devices for dental application provide the possibility of a more objective means of color determination, their performances in vitro and in vivo must be evaluated. The objective of this study was to evaluate the accuracy and precision of five commercially available tooth color-measuring devices in standardized and in clinical environments. MATERIALS AND METHODS: In an in vitro study, standards (A1, A2, A3, A3.5, and A4 shade tabs of Vita Lumin) were measured five times with five electronic devices (ShadeScan, Easyshade, Ikam, IdentaColor II, and ShadeEye) by two operators. In an in vivo study, the right upper central incisors of 25 dental students were measured with the same electronic devices by a single operator. Vita shade tab codes were expressed as CIE (International Commission on Illumination) L*a*b* values and in terms of the precision and accuracy of DeltaE color differences. The Mann-Whitney statistical test was used to analyze the differences between the two operators in the in vitro study, and the Kruskal-Wallis one-way analysis of variance on ranks with the post-hoc Tukey test was used to analyze the accuracy and precision of electronic devices. RESULTS: No statistically significant difference was found between the different operators in the in vitro study. The obtained precision was Easyshade > ShadeScan approximately equal Ikam > IdentaColor II > ShadeEye. The obtained accuracy was Easyshade > ShadeScan approximately equal Ikam > ShadeEye > IdentaColor II. In the in vivo study, the Easyshade and the Ikam were the most precise, and the ShadeEye and the IdentaColor II were more precise than the ShadeScan. With respect to accuracy, there was no statistical difference between the ShadeScan, Ikam, and the Easyshade. The IdentaColor II was considered inaccurate (DeltaE(a)= 3.4). CONCLUSIONS: In the clinical setting, the Easyshade and Ikam systems were the most reliable. The other devices tested were more reliable in vitro than in vivo.     

拔牙诱发唇血管神经性水肿1例

血管神经性水肿为一种过敏性疾病。其发病机制属I型变态反应。过敏原可能为特定的食物、药物、肠道寄生虫、感染因子等。此外，外伤、情绪激动、寒冷等可能诱发本病^[1]。我科收治1例患儿乳牙拔除后出现唇血管神经性水肿，现报告如下。     

转录调控因子CBF1（RBP—Jκ）对Cbfal和Ose2元件启动子活性的影响

目的：探讨Notch信号转录调控因子CBF1(RBP—Jκ)对核心结合因子Cbfal基因启动子和骨钙素基因启动子区域Ose2元件启动子活性的影响。方法：构建CBF1真核表达载体pCMV—Tag4／CBF1；将梯度浓度pCMV—Tag4／CBF1和荧光素酶报告质粒共转染两成骨前体细胞系Kusa—A1和Kusa-O，用双荧光素酶报告基因方法检测Cbfa1和Ose2元件启动子活性。结果：随CBF1浓度增加，Kusa—A1和Kusa-O细胞中Cbfa1和Ose2元件启动子活性均逐渐提高。统计分析表明：Kusa—A1细胞中1／40μg／μL实验组两启动子活性均与对照组差异显著；Kusa-0细胞中1／40μg／μL实验组Ose2元件启动子活性与对照组差异显著。结论：转录调控因子CBF1可以促进Cbfa1和Ose2元件启动子活性，从而可能对细胞的成骨性分化有正调节作用。     

全国第七次牙体牙髓病学学术会议纪要

由中华口腔医学会牙体牙髓病学专业委员会主办，上海交通大学医学院附属第九人民医院·口腔医学院承办的全国第七次牙体牙髓病学学术会议于2007年3月10至11日在上海召开。本次大会同时还召开了中华口腔医学会牙体牙髓病学专业委员会全体会议，进行了新一届专业委员会的换届。本次会议共收到来自全国各地28个省、市、自治区的论文共338篇，参会代表347名。[第一段]     

p53基因抑制涎腺腺样囊性癌细胞端粒酶及增殖活性

目的研究外源性野生型p53基因对涎腺腺样囊性癌细胞的抑制作用。方法构建携带野生型p53基因的腺病毒表达载体，以脂质体法转染涎腺腺样囊性癌SACC-83细胞，RT-PCR检测p53基因表达；采用TRAP—PCR—ELISA法检测转染细胞端粒酶活性，荧光素酶分析法检测人端粒酶逆转录酶基因（hTERT）肩动子的转录；流式细胞术、软琼脂集落实验及裸鼠成瘤实验观察细胞生物特性的变化。结果外源性野生型p53基因导入使p53基因在涎腺腺样囊性癌细胞SACC-83中表达增强，其端粒酶活性降低、hTERT启动子转录抑制；转染细胞出现G1期阻滞，软琼脂集落形成率减少，裸鼠成瘤能力降低。结论腺病毒载体介导的外源性野生型p53基因可以抑制涎腺腺样囊性癌细胞端粒酶活性及细胞恶性表型。     

An In Vitro Investigation of a Comparison of Bond Strengths of Composite to Etched and Air-Abraded Human Enamel Surfaces

PURPOSE: The purposes of the study were to measure the tensile bond strength of composite resin to human enamel specimens that had been either etched or air-abraded, and to compare the quality of the marginal seal, through the assessment of microleakage, of composite resin to human enamel specimens that had been either etched or air-abraded. MATERIALS AND METHODS: Thirty mandibular molar teeth were decoronated and sectioned mesio-distally to produce six groups, each containing ten specimens that were embedded in acrylic resin using a jig. In each of the four treatment groups, the specimen surfaces were treated by either abrasion with 27 or 50 microm alumina at 4 mm or 20 mm distance, and a composite resin was bonded to the treated surfaces in a standardized manner. In the two control groups the specimens were treated with 15 seconds exposure to 36% phosphoric acid gel and then similarly treated before being stored in sterile water for 1 week. All specimens were then subjected to tensile bond strength testing at either 1 or 5 mm/min crosshead speed. For the microleakage study, the degree of dye penetration was measured 32 times for each treatment group, using a neutral methylene blue dye at the interface between composite and either 27 or 50 microm air-abraded tooth structure or etched enamel surfaces. RESULTS: The mean bond strength values recorded for Group 1 (phosphoric acid etch, 5 mm/min crosshead speed) was 25.4 MPa; Group 2 (phosphoric acid etch, 1 mm/min), 22.2 MPa; Group 3 (27 microm alumina at 4 mm distance), 16.8 MPa; Group 4 (50 microm alumina at 4 mm distance), 16.9 MPa; Group 5 (27 microm alumina at 20 mm distance), 4.2 MPa; and for Group 6 (50 microm alumina at 20 mm distance) 3.4 MPa. An analysis of variance (ANOVA) demonstrated significant differences among the groups, and a multiple comparison test (Tukey) demonstrated that conventionally etched specimens had a greater bond strength than air-abraded specimen groups. No significant difference in dye penetration could be demonstrated among the groups (p= 0.58). CONCLUSIONS: Composite resin applied to enamel surfaces prepared using an acid etch procedure exhibited higher bond strengths than those prepared with air abrasion technology. The abrasion particle size did not affect the bond strength produced, but the latter was adversely affected by the distance of the air abrasion nozzle from the enamel surface. The crosshead speed of the bond testing apparatus had no effect on the bond strengths recorded. The marginal seal of composite to prepared enamel was unaffected by the method of enamel preparation.