Post-Graduate Program in Oral Sciences (Prosthodontics Units), Faculty of Dentistry, Universidade Federal de Santa Maria (UFSM), Santa Maria, Rio Grande do Sul State, Brazil.
Department of Surgical Sciences, Dental School, University of Turin (UNITO), Turin, Piedmont, Italy.
J Mech Behav Biomed Mater. 2024 Jul;155:106557. doi: 10.1016/j.jmbbm.2024.106557. Epub 2024 Apr 18.
The aim of this in vitro study was to evaluate the effect of the combinations of two different intraoral scanners (IOS), two milling machines, and two restorative materials on the marginal/internal fit and fatigue behavior of endocrowns produced by CAD-CAM. Eight groups (n= 10) were considered through the combination of TRIOS 3 (TR) or Primescan (PS) IOS; 4-axes (CR; CEREC MC XL) or 5-axes (PM; PrograMill PM7) milling machines; and lithium disilicate (LD; IPS e.max CAD) or resin composite (RC; Tetric CAD) restorative materials. Specific surface treatments were applied to each material, and the bonding to its corresponding Endocrown-shaped fiberglass-reinforced epoxy resin preparations was performed (Variolink Esthetic DC). Computed microtomography (μCT) was performed to assess the marginal/internal fit, as well as a mechanical fatigue test (20 Hz, initial load = 100 N/5000 cycles; step-size = 50 N/10,000 cycles until a threshold of 1500 N, then, the step-size was increased if needed to 100 N/10,000 cycles until failure or a threshold of 2800 N) to evaluate the restorations long-term behavior. Complementary analysis of the fracture features and surface topography in scanning electron microscopy was performed. Three-way ANOVA and Kaplan-Meier test (α = 0.05) were performed for marginal/internal fit, and fatigue behavior data, respectively. PS scanner, CR milling machine, and RC endocrowns resulted in a better marginal fit compared to their counterparts. Still, the PM machine resulted in a better pulpal space fit compared to the CR milling machine. Regardless of the scanner and milling machine, RC endocrowns exhibited superior fatigue behavior than LD ones. LD endocrowns presented margin chipping regardless of the milling machine used. Despite minor differences in terms of fit, the 'IOS' and 'milling machine' factors did not impair the fatigue behavior of endocrowns. Resin-composite restorations resulted in a higher survival rate compared to glass-ceramic ones, independently of the digital devices used in the workflow.
本体外研究旨在评估两种不同口内扫描仪（IOS）、两种铣削机和两种修复材料组合对 CAD-CAM 制作的嵌体的边缘/内部适合度和疲劳性能的影响。通过 TRIOS 3（TR）或 Primescan（PS）IOS 的组合；四轴（CR；CEREC MC XL）或五轴（PM；PrograMill PM7）铣削机；以及二硅酸锂（LD；IPS e.max CAD）或树脂复合材料（RC；Tetric CAD）修复材料，考虑了 8 组（n=10）。对每种材料进行了特定的表面处理，并将其与相应的纤维增强环氧树脂制备的嵌体形状进行了粘结（Variolink Esthetic DC）。通过计算机微断层扫描（μCT）评估边缘/内部适合度，以及进行机械疲劳试验（20 Hz，初始载荷=100 N/5000 循环；步长=50 N/10,000 循环，直到达到 1500 N 的阈值，然后，如果需要，将步长增加到 100 N/10,000 循环，直到失效或达到 2800 N 的阈值），以评估修复体的长期性能。通过扫描电子显微镜对断裂特征和表面形貌进行了补充分析。分别对边缘/内部适合度和疲劳行为数据进行了三向方差分析和 Kaplan-Meier 检验（α=0.05）。PS 扫描仪、CR 铣床和 RC 嵌体的边缘适合度优于其对应物。然而，PM 机器的牙髓空间适合度优于 CR 铣床。无论使用哪种扫描仪和铣床，RC 嵌体的疲劳性能均优于 LD 嵌体。无论使用哪种铣床，LD 嵌体均出现边缘崩裂。尽管在适合度方面存在微小差异，但“IOS”和“铣床”因素并未影响嵌体的疲劳性能。树脂复合材料修复体的存活率高于玻璃陶瓷修复体，与工作流程中使用的数字设备无关。
