Department of Prosthodontics, Bernhard Gottlieb University Clinic of Dentistry, Medical University of Vienna, Austria.
Dent Mater. 2011 Sep;27(9):855-69. doi: 10.1016/j.dental.2011.05.002. Epub 2011 Jun 23.
Microleakage testing of dental materials is a commonly accepted evaluation technique of margin integrity. Thermocycling has been utilized by many researchers to study the influence of temperature extremes on the marginal gap of cemented restorations. The aim of this investigation was to analyze microleakage data on cemented crowns, published in the dental literature until Dec 2009, to identify methodological factors that might potentially affect the results of in vitro microleakage tests and to compare the results.
The following databases were included: Ovid MEDLINE(R) In-Process & Other Non-Indexed Citations and Ovid MEDLINE(R) 1950 to Present, Ovid-MEDLINE(R) 1950 to Present with Daily Update, EMBASE, EBM Reviews - Cochrane Database of Systematic Reviews and Pub Med. The search was limited to articles in English, French, Italian and German published until the end of 2009. Classical reviews, comments, animal studies, in vivo articles and studies investigating restorative materials or milk teeth were excluded. 33 different studies were finally selected. The studies were entered in a database and compared using selected literature criteria: sample, restoration procedures, thermocycling and mechanical cycling, evaluation method. For statistical analysis only 16 studies could be applied.
It was not possible to make a quantitative synthesis of most of the data, due to the heterogeneity of the studies concerning methods, treatment and outcome variables. Comparing the main groups of materials (ceramics, gold alloys and base metal alloys), no significant difference in the proportion of teeth without microleakage was found. Furthermore no significant difference in the proportion of teeth showing microleakage less than two third of the wall or teeth showing microleakage including the entire wall was found. Using the mean values in the meta-analysis instead of the proportions does not change the results. Confidence intervals could only be calculated for two materials (gold alloy, metal alloy). No difference between materials was found.
Comparison of the results from different studies is critical, since there are no generally accepted standards for experimental parameters, such as type and concentration of the storage solution, time of storage, temperature during storage, type and duration of thermal cycling and/or mechanical cycling, and the scoring criteria. There is lack of standardization of experimental conditions, which would ensure confidence in the studies and would further allow better comparability of various results.
对牙科材料进行微渗漏测试是评估边缘完整性的常用方法。许多研究人员利用冷热循环来研究极端温度对粘结修复体边缘间隙的影响。本研究的目的是分析截至 2009 年 12 月发表在牙科文献中的粘结冠的微渗漏数据，以确定可能影响体外微渗漏测试结果的方法学因素，并进行比较。
纳入了以下数据库：Ovid MEDLINE(R)在处理及其他非索引引用和 Ovid MEDLINE(R)1950 年至今，Ovid-MEDLINE(R)1950 年至今每日更新，EMBASE，EBM Reviews - Cochrane 系统评价数据库和 Pub Med。检索限定于英语、法语、意大利语和德语发表的文章，时间截至 2009 年底。经典综述、评论、动物研究、体内研究以及研究修复材料或乳齿的文章均被排除。最终选择了 33 项不同的研究。将研究录入数据库，并使用选定的文献标准进行比较：样本、修复程序、冷热循环和机械循环、评估方法。由于研究方法、处理和结果变量存在异质性，仅有 16 项研究可用于统计学分析。
由于研究方法、处理和结果变量存在异质性，大多数数据无法进行定量综合。比较主要材料组（陶瓷、金合金和贱金属合金），发现无微渗漏的牙齿比例无显著差异。此外，微渗漏小于壁的三分之二的牙齿和微渗漏包括整个壁的牙齿比例也无显著差异。在荟萃分析中使用平均值而不是比例不会改变结果。置信区间只能计算两种材料（金合金、金属合金）。未发现材料之间有差异。
由于缺乏关于实验参数的普遍接受的标准，例如储存溶液的类型和浓度、储存时间、储存期间的温度、热循环和/或机械循环的类型和持续时间以及评分标准，因此比较不同研究的结果至关重要。实验条件缺乏标准化，这将确保对研究的信心，并进一步提高对各种结果的可比性。
