Dr. Kayal is in private practice, Alkhobar, Saudi Arabia;, Email:
Dr. Kang is an associate professor in residence, Department of Clinical Sciences, University of Nevada Las Vegas, Las Vegas, Nev.
Pediatr Dent. 2023 Mar 15;45(2):142-146.
The purpose of this study was to compare the retention of 3M stainless steel crowns (SSCs), Kinder Krowns zirconia crowns (ZCs), and EZCrowns ZCs on extracted primary mandibular second molars ex-vivo.
A total of 45 extracted primary mandibular second molars were allocated randomly to either of the three groups. All teeth were mounted in Dentsply acrylic molds and then prepared for crown cementation. Crowns were cemented with glass ionomer cement (GIC). Retention testing was performed using Instron 5566A. Differences in retention between the groups were tested via Welch's analysis of variance (ANOVA), and post hoc comparisons were performed with the Games-Howell test.
Welch's ANOVA resulted in statistically significant differences between the three groups (P<0.001). The mean±SD force in Newtons (N) for the SSC group, Kinder Krowns group, and EZCrowns group were 337.0±137.1 N, 89.4±53.6 N, and 106.5±77.7 N, respectively. Post hoc comparisons with the Games-Howell test presented that the SSC group had significantly higher retention than both the ZC groups (P<0.001). There was no significant difference between the ZC groups (P=0.76).
Within the limitations of this ex-vivo study results, due to their statistically significant higher retention, stainless steel crowns should be selected over zirconia crowns when in need of a full coverage restoration. But if esthetics are a concern, dentists can choose freely between either of the ZCs tested in this study.
本研究旨在比较 3M 不锈钢冠（SSC）、Kinder Krowns 氧化锆冠（ZC）和 EZCrowns ZC 在离体下颌第二乳磨牙上的保留情况。
共 45 颗离体下颌第二乳磨牙随机分为三组。所有牙齿均固定在 Dentply 丙烯酸模具上，然后进行冠粘固准备。冠用玻璃离子水门汀（GIC）粘固。采用 Instron 5566A 进行保留力测试。采用 Welch 方差分析（ANOVA）比较组间保留力差异，并用 Games-Howell 检验进行事后比较。
Welch ANOVA 显示三组间存在统计学差异（P<0.001）。SSC 组、Kinder Krowns 组和 EZCrowns 组的平均保留力（N）分别为 337.0±137.1 N、89.4±53.6 N 和 106.5±77.7 N。Games-Howell 检验结果表明，SSC 组的保留力明显高于 ZC 组（P<0.001）。两组 ZC 组之间无显著差异（P=0.76）。
在本离体研究结果的限制范围内，由于不锈钢冠具有统计学上更高的保留力，在需要全冠修复时，应优先选择不锈钢冠而非氧化锆冠。但如果关注美观，牙医可以在本研究中测试的两种 ZC 之间自由选择。
