Pilecco Rafaela Oliveira, Rosa Lucas Saldanha da, Baldi Andrea, Machry Renan Vaz, Tribst João Paulo Mendes, Valandro Luiz Felipe, Kleverlaan Cornelis Johannes, Scotti Nicola, Pereira Gabriel Kalil Rocha
Department of Conservative Dentistry, Faculty of Dentistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil.
Post-Graduate Program in Oral Sciences (Prosthodontics Units), Faculty of Dentistry, Universidade Federal de Santa Maria (UFSM), Santa Maria, Rio Grande do Sul, Brazil.
Eur J Dent. 2025 Jul;19(3):638-649. doi: 10.1055/s-0044-1791705. Epub 2025 Mar 12.
To analyze the marginal/internal gap and the fatigue behavior of crowns made of two different materials, using four combinations of a digital workflow-two intraoral scanners (IOSs) and two milling machines.
Crowns were made considering three factors: IOS (a confocal microscopy-based scanner: TRIOS 3-TR; or a combination of active triangulation and dynamic confocal microscopy: Primescan-PS), milling machines (four-axis: CEREC MC XL-CR or five-axis: PrograMill PM7-PM), and restorative material (lithium disilicate-LD or resin composite-RC) ( = 10). The bonding surface of each crown was treated and bonded to each respective glass fiber-reinforced epoxy resin die using a dual-cure resin cement. A computed microtomography analysis was performed to access marginal/internal gap. The specimens were subjected to a cyclic fatigue test (20 Hz, initial load = 100 N/5,000 cycles; step size= 50 N/10,000 cycles until 1,500 N, then if specimens survived, the step size was increased to 100 N/10,000 cycles).
For data analysis, three-way analysis of variance and Kaplan-Meier with log-rank (Mantel-Cox) test were performed (α = 0.05).
TR resulted in a smaller axial-occlusal angle and occlusal gap, and five-axis milling resulted in a smaller marginal gap, axial-occlusal angle, and occlusal gap. Angled points and occlusal surface showed a tendency for overmilling. RC crowns displayed higher survival rates and a more pronounced topography compared with LD independently of the scanning and milling method. LD crowns produced with a five-axis milling machine resulted in higher fatigue performance and rougher topography compared with a four-axis machine.
RC crowns displayed better fatigue behavior compared with LD, while LD benefited from a five-axis machine for improved survival probability.
使用数字工作流程的四种组合——两种口内扫描仪（IOS）和两种铣床，分析由两种不同材料制成的牙冠的边缘/内部间隙和疲劳行为。
制作牙冠时考虑三个因素：IOS（基于共聚焦显微镜的扫描仪：TRIOS 3-TR；或主动三角测量与动态共聚焦显微镜的组合：Primescan-PS）、铣床（四轴：CEREC MC XL-CR或五轴：PrograMill PM7-PM）以及修复材料（二硅酸锂-LD或树脂复合材料-RC）（=10）。对每个牙冠的粘结面进行处理，并使用双固化树脂粘结剂将其粘结到各自的玻璃纤维增强环氧树脂代型上。进行计算机断层扫描分析以获取边缘/内部间隙。对样本进行循环疲劳测试（20Hz，初始载荷=100N/5000次循环；步长=50N/10000次循环，直至1500N，然后如果样本存活，步长增加到100N/10000次循环）。
进行数据分析时，采用三因素方差分析以及带有对数秩（Mantel-Cox）检验的Kaplan-Meier分析（α=0.05）。
TR导致较小的轴-咬合角和咬合间隙，五轴铣削导致较小的边缘间隙、轴-咬合角和咬合间隙。角点和咬合面有过度铣削的趋势。与LD相比，无论扫描和铣削方法如何，RC牙冠均显示出更高的存活率和更明显的表面形貌。与四轴铣床相比，使用五轴铣床制作的LD牙冠具有更高的疲劳性能和更粗糙的表面形貌。
与LD相比，RC牙冠表现出更好的疲劳行为，而LD受益于五轴铣床以提高存活概率。
