三种新型可聚合抗菌单体对口腔病原菌的抗菌活性研究

目的:比较自行合成的3种可聚合季铵盐抗菌单体DMAE-MMA salt,DMAEMA-MMA salt,DMAEMA-PMDPM salt对口腔常见致病菌的抗菌活性。方法:采用液体稀释法测定季铵盐单体对4种口腔常见致病菌的抗菌活性,以抗菌性能最佳的单体进行杀菌动力学研究。结果:3种季铵盐单体对4种口腔致病菌均表现出一定的抗菌活性,其中DMAEMA-PMDPM salt抗菌效果较其它2种好,该单体在浓度为78.8 mg/ml即4倍MBC浓度时,白色念珠菌与其接触120 min时可达到灭菌效果。结论:这3种季铵盐单体对常见口腔致病菌均表现出一定的抗菌活性。     

四种根管封闭剂抗微生物作用的体外评价

目的观察四种根管封闭剂的抗微生物作用:纳米氧化锌糊剂(N-ZO),纳米羟磷灰石糊剂(NHA),AH Plus,mineral trioxide aggregate(MTA)。方法采用琼脂扩散法,选择金黄色葡萄球菌、白色念珠菌、粪肠球菌、大肠杆菌作为实验菌种。观察37℃培养24小时的抑菌环直径。结果 MTA和NHA均没有显示出抑菌作用,只有AH Plus与N-ZO组对金黄色葡萄球菌、白色念珠菌、大肠杆菌有抑菌作用。其中N-ZO产生了最大的抑菌范围从8mm至18mm,粪肠球菌对所有的实验材料都抵抗。结论纳米氧化锌糊剂和AH Plus具有较强的抗微生物作用,而MTA和纳米羟磷灰石糊剂无抑菌作用。所有实验材料对粪肠球菌都没有抑菌作用。     

自酸蚀粘结剂应用于年轻恒中切牙冠折修复的效果

目的评价自酸蚀粘结剂用于年轻恒中切牙冠折充填修复治疗的效果。方法选择年轻恒上颌中切牙牙冠牙釉质-牙本质折断而未露髓的患者106例137颗患牙,按抛硬币方法分为试验组和对照组。试验组的56例74颗患牙使用自酸蚀粘结剂处理牙面;对照组的50例63颗患牙常规间接盖髓、酸蚀剂和粘结剂处理牙面。2组用相同光固化复合体修复牙冠外形,调牙合抛光,观察2组修复后1个月、3个月、6个月、1年、2年的疗效。结果治疗后1个月、3个月、6个月、1年、2年,试验组成功率分别为97.30%、97.30%、94.59%、94.59%、94.59%,对照组成功率分别为95.24%、95.24%、90.48%、88.89%、88.89%,试验组成功率高于对照组,但差异均无统计学意义(P>0.05)。结论应用自酸蚀粘结剂粘结充填修复牙釉质-牙本质折断而未露髓的年轻恒中切牙效果良好。     

多媒体技术在口腔材料性能教学中的应用

为进一步优化教育管理和教学过程,适应教育改革的潮流和趋势,教育部于1999年就已提出,在高校普及和运用以多媒体计算机技术为核心的教育技术应用模式是推进教育信息化进程的关键一步.按照这一思路,北京大学口腔医学院尝试对口腔材料学材料性能的教学方式进行改革,引入多媒体技术.通过对教学内容进行深入分析,将课程讲授重点分别采用动画短片和录像方式进行详尽的讲解,其他概念多配以图片进行讲解.课件制作完成后,在2006级和2007级的八年制学生中进行了实际使用,并根据课件内容设计了调查问卷,调查问卷结果显示,课件教学效果良好.     

Minimal intervention concept: a new paradigm for operative dentistry

The current treatment philosophy is to prevent and detect dental disease at the earliest stage in order to avoid invasive treatment. With the current understanding of the nature of dental disease and its process, the treatment philosophy is now changing to a more conservative approach and the concept of minimal intervention is gaining popularity in modern dentistry throughout the world. It is now established that demineralized but non-cavitated enamel and dentine can be healed and traditional surgical approach of drilling and filling may no longer be necessary as this only treats the symptoms of the disease and not the cause. However, when surgical intervention is indicated, the least invasive techniques such as preventive resin restoration and minimal cavity preparation are utilized. The aim of this article is to give dental professionals an overview of the concepts of minimal intervention dentistry and recent innovations in dental technology in both the diagnosis and treatment of dental caries.     

Art materials and processes – a place of meeting art psychotherapy with a four-year-old boy

Abstract

This article explores the complex role of art materials and processes in art psychotherapy with a four-year-old boy with developmental delay. Individual art psychotherapy sessions were conducted over an eighteen-month period. By focusing in detail on work done in the first seven months of his therapy, the author is able to highlight the multifaceted role played by art materials and processes in supporting therapeutic change. The pivotal role played by engagement with the art materials paint, water, sand, whiteboard and clay is described in detail. Initial negotiations that focused on the boys use of and relationship with the materials laid the foundations of a relationship with his therapist in which he was able to develop an internal space that was separate from outside experience and so begin to develop an independent identity. Countertransference was used as a tool for understanding the boys interactions with the materials, for finding meaning in apparent mindlessness and for providing containment in order to lay the foundations of a sense of self. This assisted the development of his language and ability to play in the sessions as well as supporting his social development in his family and elsewhere. The authors arguments are contextualised in current art therapy theory as well as with reference to psychoanalytic concepts, child psychotherapy and art education.     

The effect of temperature changes on adaptation of resin fillings. II

In earlier laboratory investigations of thermal percolation at resinous fillings the duration of the heating periods was too long to be realistic. The aim of the present work was to investigate the effect of repeated heatings of realistic duration on the formation of marginal gaps between filling and tooth during a subsequent cooling below the minimum value in the temperature cycling process. Fillings made in extracted human teeth were studied. The brands investigated were Adaptic, Blendànt, Concise, Opotow, Sevriton Simplified, and Swedon. After closure of the initial gaps by water absorption expansion the fillings were polished and subjected to thermal cycling. The specimens were cycled between either 37° and 50° C or 37° and 60° C, the duration of each immersion in the warmer bath was 2 or 5 seconds, and the number of cycles was 1, 10, 100 or 1000. The effect of the cycling was investigated by measuring the width of marginal gaps appearing at a temperature lower than 37° C. It was found that the width of the gaps was only little affected by thermal cycling between 37° and 50° C. Cycling between 37° and 60° C increased the gap widths only with Opotow, Sevriton Simplified, and Swedon. The data indicate that thermal percolation for a number of brands may be of no clinical importance.     

Patients' choice of dental treatment following examination at a specialty unit for adverse reactions to dental materials

The Dental Biomaterials Adverse Reaction Unit in Bergen, Norway, is a national unit for the examination of patients with suspected adverse reactions to dental materials. The aim of this study was to investigate whether patients with suspected adverse reactions to dental materials experienced improvement in health after dental restorations had been replaced, and whether they had acted according to the recommendations of the Unit. A questionnaire was sent to 358 patients who had been examined at the Unit 18 months to 7 years earlier. Of the 207 patients who completed the questionnaire, 85 had had restorative materials replaced with other types of materials. A majority had had amalgam fillings replaced. After replacement, 51 patients reported an improvement in health. Twelve patients reported that they felt worse after replacement. The Unit recommended replacement of materials in 31 patients, of whom 24 followed the recommendation. Among 176 patients who were not given specific recommendations as to replacement of dental materials, 67 had had their restorations replaced, and 40 had started to have them replaced. It appears that the examination at the Dental Biomaterials Adverse Reaction Unit is one of several inputs that influence a person's decision to replace dental materials.     

Determination of the Movements of Impacted Upper Canines by X-Ray Photogrammetric Methods

Samples of gold soldered assemblies from three different dental casting gold alloys were subjected to various homogenizing heat treatments. The distribution of available alloy components in the region of the gold-solder junction was investigated using electron-probe micro-analysis. An extensive statistical treatment of the data was performed. Concentration differences between casting alloy and solder alloy were not levelled out to any great extent unless after prolonged heat treatment (3 hours) for one of the three alloys. However, this heat treatment caused grain growth and an increased amount of microporosities in the region of the joint. In the soldered assemblies from two of the three casting alloys microphases with a composition different from the original alloys appeared at the gold-solder junction after heat treatment. The results show that homogenizing heat treatment of gold soldered assemblies should not be performed as a routine.