Salama Mohamed A, Aldamaty Mohamed F, Abdalla Moamen A, Omar Elsayed Ali, AbdElaziz Mohammed H, Alqutaibi Ahmed Yaseen
Fixed Prosthodontic Specialist, Medical Services of the Egyptian Armed Forces, Basrah, Egypt.
Department of Fixed Prosthodontics, Faculty of Dental Medicine, Al-Azhar University, Cairo, Egypt.
Clin Exp Dent Res. 2025 Feb;11(1):e70064. doi: 10.1002/cre2.70064.
The use of vertical margin design in all-ceramic restoration has generated inquiries regarding its clinical efficacy under diverse dynamic oral conditions. This research aims to assess the marginal fit and fracture resistance of monolithic zirconia crowns featuring vertical margin design as opposed to those with conventional horizontal margin design.
Two metal dies were employed to generate replicated resin dies mimicking mandibular first molar preparation. The metal dies were precision-engineered with two margin designs: vertical margin design presenting a shoulderless configuration (Featheredge) and horizontal margin design (Radial Shoulder). Forty zirconia crowns were produced on the replicated resin dies using two varieties of monolithic zirconia, with twenty crowns in each category: pre-shaded and multilayered zirconia. Both sets were further subdivided into two groups based on the finish line configuration utilized (n = 10). The vertical marginal gap of the zirconia crowns was gauged before and after thermocycling (5-55oC/5000 cycles), followed by loading the crowns until fracture occurred. Statistical analysis was performed using one-way analysis of variance (ANOVA), accompanied by Bonferroni's post hoc test and independent t-test for pairwise comparisons.
The Shoulder subgroup of BruxZir exhibited the highest mean marginal gap value (120.06 ± 10.15 µ), while the Featheredge subgroup of BruxZir displayed the lowest value (49.72 ± 6.53 µ). Among the BruxZir group, the Featheredge subgroup showcased the highest mean fracture resistance value (4251.57 ± 279.90 N), whereas the Shoulder subgroup recorded the lowest value (1721.60 ± 225.16 N).
Monolithic zirconia crowns with vertical margin design (Featheredge) demonstrated statistically enhanced performance compared to conventional horizontal margin design, as evidenced by lower marginal gap values and increased fracture resistance tolerance.
全瓷修复中垂直边缘设计的应用引发了人们对其在不同动态口腔条件下临床疗效的质疑。本研究旨在评估采用垂直边缘设计的整体式氧化锆全冠与传统水平边缘设计的全冠相比的边缘适合性和抗折性。
使用两个金属代型制作模拟下颌第一磨牙预备的复制树脂代型。金属代型采用两种边缘设计进行精密加工：垂直边缘设计呈现无肩台形态（薄刃状）和水平边缘设计（径向肩台）。使用两种整体式氧化锆在复制树脂代型上制作40个氧化锆全冠，每种类型20个：预染色氧化锆和多层氧化锆。两组均根据所使用的边缘线形态进一步细分为两组（n = 10）。在热循环（5 - 55°C/5000次循环）前后测量氧化锆全冠的垂直边缘间隙，然后对全冠进行加载直至发生断裂。使用单因素方差分析（ANOVA）进行统计分析，并采用Bonferroni事后检验和独立t检验进行两两比较。
BruxZir的肩台亚组显示出最高的平均边缘间隙值（120.06 ± 10.15 µm），而BruxZir的薄刃状亚组显示出最低值（49.72 ± 6.53 µm）。在BruxZir组中，薄刃状亚组展示出最高的平均抗折性值（4251.57 ± 279.90 N），而肩台亚组记录到最低值（1721.60 ± 225.16 N）。
与传统水平边缘设计相比，采用垂直边缘设计（薄刃状）的整体式氧化锆全冠在统计学上表现出更好的性能，表现为更低的边缘间隙值和更高的抗折性耐受性。
