Boeckler Arne F, Stadler Anke, Setz Jürgen M
Department of Prosthodontics, Martin-Luther-University Halle-Wittenberg, Halle, Germany.
J Contemp Dent Pract. 2005 Nov 15;6(4):26-37.
An important criterion for the success of a crown is marginal fit. However, in the patient's mouth fit can only be evaluated by subjective methods. This study describes the correlation between objective marginal fit and its subjective evaluation by dentists and dental technicians.
Thirty human premolars and molars were randomly divided into six groups and prepared with a shoulder. For each of the six groups, complete crowns were made of different alloys and technologies (casting: AuAgCu, AuPdPt, PdAgAu, CoCrMo, and Ti; milling: Ti). The crowns were cemented with provisional cement. Ten dentists and 10 technicians were asked to evaluate the fit of the crowns with a new dental explorer. The crowns were then cleaned and cemented with a zinc-oxide-phosphate-cement. The marginal gap and a possible overextended margin of the crowns were examined under a special 4x light microscope with a magnification level of 560 X. The means of the gaps and the overextended margins were calculated for each group. Significances were detected by analysis of variance (ANOVA) and the post-hoc-test (Bonferroni, p<0.05). Correlations between objective measuring and subjective evaluation were evaluated using the Pearson test. The influence of the measured values on the subjective evaluation was determined by regression analyses.
Crowns made from different alloys and technologies showed partly significantly (p<0.05) different marginal gaps (mean ranging from 35 microm to 92 microm) and significantly (p<0.05) different overextended margins (mean ranging from 40 microm to 149 microm). There were significant correlations (p<0.05) between subjective findings and objective data. Significant correlations (p<0.01) were also found between the subjective findings of dentists and technicians. Compared to the marginal gap, only the overextended margin had a significant influence (p=0.00) on the subjective evaluations of the clinicians.
Crowns from different alloys and technologies showed differences in marginal fit. Marginal gap and the overextension of the crowns significantly correlated with the subjective evaluation of their fit by dentists and dental technicians. For the decision of the clinicians, whether a crown is acceptable, overextension was more important than marginal gap.
牙冠成功的一个重要标准是边缘适合性。然而，在患者口腔中，适合性只能通过主观方法进行评估。本研究描述了客观边缘适合性与其由牙医和牙科技师进行的主观评估之间的相关性。
将30颗人类前磨牙和磨牙随机分为六组，并制备成带肩台的形态。对于这六组中的每一组，用不同的合金和技术制作全冠（铸造：金银铜、金钯铂、钯银金、钴铬钼和钛；铣削：钛）。用临时粘固剂粘固牙冠。邀请10名牙医和10名牙科技师用新型牙科探针评估牙冠的适合性。然后清洁牙冠并用磷酸锌粘固剂粘固。在一台放大倍数为560倍的特殊4倍光学显微镜下检查牙冠的边缘间隙和可能存在的边缘过度伸展情况。计算每组间隙和边缘过度伸展情况的平均值。通过方差分析（ANOVA）和事后检验（Bonferroni法，p<0.05）检测显著性。使用Pearson检验评估客观测量与主观评估之间的相关性。通过回归分析确定测量值对主观评估的影响。
由不同合金和技术制作的牙冠显示出部分显著（p<0.05）不同的边缘间隙（平均值范围为35微米至92微米）和显著（p<0.05）不同的边缘过度伸展情况（平均值范围为40微米至149微米）。主观结果与客观数据之间存在显著相关性（p<0.05）。在牙医和牙科技师的主观结果之间也发现了显著相关性（p<0.01）。与边缘间隙相比，只有边缘过度伸展情况对临床医生的主观评估有显著影响（p=0.00）。
不同合金和技术制作的牙冠在边缘适合性方面存在差异。牙冠的边缘间隙和边缘过度伸展情况与牙医和牙科技师对其适合性的主观评估显著相关。对于临床医生决定牙冠是否可接受而言，边缘过度伸展比边缘间隙更重要。
