Kist Stefan, Stawarczyk Bogna, Kollmuss Maximilian, Hickel Reinhard, Huth Karin C
Department of Conservative Dentistry and Periodontology, University Hospital, LMU Munich, Munich, Germany.
Department of Prosthetic Dentistry, University Hospital, LMU Munich, Munich, Germany.
Eur J Oral Sci. 2019 Aug;127(4):369-375. doi: 10.1111/eos.12645. Epub 2019 Jul 10.
Aesthetic alternatives to stainless-steel crowns for restoring primary molars attain growing interest. We studied the mechanical properties of prefabricated zirconia crowns and conventional crowns. Three brands of prefabricated zirconia crowns were compared with computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia crowns, preveneered stainless-steel crowns, and conventional stainless-steel crowns regarding: (i) fracture load under each of three conditions [no pretreatment, artificial aging in saliva for 12 wk, and after chewing simulation/thermocycling (1.68 × 10 cycles/5-55°C)]; and (ii) survival rate during chewing simulation, considering decementation, fracture, chipping, fatigue cracks, and occlusal holes. Without pretreatment, the prefabricated zirconia crowns showed mean fracture load values between 893 N and 1,582 N, while the corresponding values for CAD/CAM zirconia crowns and preveneered stainless-steel crowns were 2,444 N and 6,251 N. Preveneered stainless-steel crowns showed significantly lower fracture loads after artificial aging (5,348 N after saliva aging; 3,778 N after chewing simulation) than without artificial aging, whereas the fracture load of zirconia crowns was not influenced negatively. The survival rate of the different groups of zirconia crowns and preveneered stainless-steel crowns during chewing simulation was 100%, but only 41.7% for the stainless-steel crowns. These in-vitro data suggest that prefabricated zirconia crowns are aesthetically and durable alternatives to stainless-steel crowns for primary molars.
用于修复乳磨牙的不锈钢冠的美学替代方案越来越受到关注。我们研究了预制氧化锆冠和传统冠的力学性能。将三个品牌的预制氧化锆冠与计算机辅助设计/计算机辅助制造（CAD/CAM）氧化锆冠、预涂覆不锈钢冠和传统不锈钢冠在以下方面进行了比较：（i）三种条件下的断裂载荷[无预处理、在唾液中人工老化12周以及咀嚼模拟/热循环后（1.68×10次循环/5-55°C）]；（ii）咀嚼模拟期间的存活率，考虑脱粘、断裂、崩裂、疲劳裂纹和咬合洞。未经预处理时，预制氧化锆冠的平均断裂载荷值在893 N至1582 N之间，而CAD/CAM氧化锆冠和预涂覆不锈钢冠的相应值分别为2444 N和6251 N。预涂覆不锈钢冠在人工老化后（唾液老化后为5348 N；咀嚼模拟后为3778 N）的断裂载荷明显低于未进行人工老化时，而氧化锆冠的断裂载荷未受到负面影响。不同组的氧化锆冠和预涂覆不锈钢冠在咀嚼模拟期间的存活率为100%，但不锈钢冠的存活率仅为41.7%。这些体外数据表明，预制氧化锆冠是乳磨牙不锈钢冠在美学和耐用性方面的替代选择。
