Zenthöfer Andreas, Ilani Ali, Rues Stefan
Department of Prosthodontics, University Clinic Heidelberg, University of Heidelberg, Heidelberg, Germany.
Int J Dent. 2024 Oct 9;2024:2037792. doi: 10.1155/2024/2037792. eCollection 2024.
To evaluate the fracture resistance of veneered incisor crowns made from highly translucent zirconia frameworks. Ninety-six all-ceramic single crowns were based on either a coping with minimum wall thickness or a cutback framework fabricated from highly translucent zirconia (5Y-PSZ). Each one-third of the specimens was finalized with different veneering ceramics using standardizations and glaze firing. Crowns were luted to cobalt-chromium dies with MDP-containing composite cement. Half of the entire sample underwent artificial aging (chewing simulation and thermocycling) before fracture load tests were conducted using a 6 mm steel sphere applied in a 90° angle to the oral aspect of the crowns with 1.3 mm distance to the incisal edge. Besides descriptive presentation of recorded forces at first damage (F) and fracture (F), Kruskal Wallis and Mann-Whitney tests were used to analyze data at = 0.05. Directly after manufacturing, incisor crowns of all test groups showed sufficient mean fracture resistances. After artificial aging, crack formation was observed in a high percentage for fully veneered crowns of all test groups, but only for one veneering ceramics with cutback crowns. Mean test forces of unaged crowns were F ≥ 422 N | F ≥ 749 N (fully veneered) and F ≥ 644 N | F ≥ 706 N (cutback) dropped significantly to F ≥ 131 N | F ≥ 223 N (fully veneered) and F ≥ 324 N | F ≥ 524 N (cutback) . Within the limitations of this laboratory study, 5Y-PSZ based anterior crowns can be a viable treatment option. Framework design, choice of the veneering ceramics and artificial aging show relevant effects on the fracture resistances. Concerted veneering ceramics should be used and partially veneering of the zirconia frameworks should be favored over full veneers.
评估由高透明度氧化锆框架制成的贴面切牙冠的抗折性。96个全瓷单冠基于最小壁厚的内冠或由高透明度氧化锆（5Y-PSZ）制成的回切框架。使用标准化和釉烧工艺，每组三分之一的标本用不同的贴面陶瓷完成制作。用含MDP的复合树脂水门汀将牙冠粘结到钴铬代型上。在进行断裂载荷测试之前，对整个样本的一半进行人工老化（咀嚼模拟和热循环），使用一个6毫米的钢球以90°角施加到牙冠的口腔面，距切缘1.3毫米。除了描述首次损伤（F）和断裂（F）时记录的力外，还使用Kruskal Wallis和Mann-Whitney检验在α=0.05时分析数据。在制造后，所有测试组的切牙冠均显示出足够的平均抗折性。人工老化后，所有测试组的全瓷贴面冠均有很高比例出现裂纹形成，但回切冠只有一种贴面陶瓷出现裂纹。未老化牙冠的平均测试力为F≥422 N | F≥749 N（全瓷贴面）和F≥644 N | F≥706 N（回切），显著下降至F≥131 N | F≥223 N（全瓷贴面）和F≥324 N | F≥524 N（回切）。在本实验室研究的局限性内，基于5Y-PSZ的前牙冠可能是一种可行的治疗选择。框架设计（回切与否）、贴面陶瓷的选择和人工老化对抗折性有显著影响。应使用配套的贴面陶瓷，相对于全瓷贴面，氧化锆框架的部分贴面应更受青睐。
