Velôso Daniele Valente, Barbin Thaís, Del Rio Silva Letícia, Barão Valentim A R, Mesquita Marcelo Ferraz, Borges Guilherme Almeida
Research Fellow, Department of Prosthodontics and Periodontology, Piracicaba Dental School, Universidade Estadual de Campinas (UNICAMP), Piracicaba, São Paulo, Brazil.
Associate Professor, Department of Prosthodontics and Periodontology, Piracicaba Dental School, Universidade Estadual de Campinas (UNICAMP), Piracicaba, São Paulo, Brazil.
J Prosthet Dent. 2025 Sep;134(3):783.e1-783.e9. doi: 10.1016/j.prosdent.2025.04.042. Epub 2025 May 21.
Titanium frameworks for implant-supported fixed prostheses can be fabricated through subtractive or additive manufacturing using computer-aided design and computer-aided manufacturing (CAD-CAM) systems. However, the accuracy achieved by these technologies remains uncertain.
The purpose of this in vitro study was to evaluate complete arch maxillary fixed prostheses supported by 6 implants using CAD-CAM frameworks manufactured by milling and 3D printing technologies, selective laser melting (SLM), and electron beam melting (EBM) on the marginal fit and screw loosening torque before and after masticatory simulation.
Ti-6Al-4V frameworks were manufactured by milling, SLM, and EBM technologies (n=5) and were subsequently ceramic veneered. The surface topography of the framework was assessed by scanning electron microscopy and laser scanning confocal microscopy. One-way analysis of variance (ANOVA) was used to evaluate surface area. The specimens were further evaluated for the dependent variables (marginal fit and screw loosening torque) before and after masticatory simulation. Two-way repeated measures ANOVA and the Pearson correlation were performed (α=.05).
Topographical analysis demonstrated that the milling group had a smooth surface (surface area: 1.17 ±0.02 µm) with regular regions, while additive manufacturing groups showed a dendritic profile with higher surface area (SLM: 1.23 ±0.05 µm; EBM: 1.21 ±0.03 µm; P<.05). A 2-way ANOVA found no interaction between technology and time (P>.05) for both dependent variables. Marginal fit showed no further significant differences regarding either the manufacturing technology or the evaluation time. Masticatory simulation reduced screw loosening torque (P=.032). Regarding manufacturing technology, milling resulted in a higher screw loosening torque compared with SLM (P=.01); however, no difference was observed between EBM and either SLM or milling (P>.05). A moderate correlation (P=.02) between marginal fit and screw loosening torque was observed only at baseline for the pooled CAD-CAM (milling, SLM, and EBM) specimens.
CAD-CAM complete arch fixed prostheses on 6 implants made by milling, SLM, and EBM exhibited marginal fit values below the acceptable error limits. Regarding prosthetic screw loosening torque, the pooled milled frameworks showed better values compared with SLM. After masticatory simulation, prosthetic screw stability decreased in all prostheses.
用于种植体支持的固定修复体的钛框架可以通过使用计算机辅助设计和计算机辅助制造（CAD-CAM）系统的减材制造或增材制造来制作。然而，这些技术所达到的精度仍不确定。
本体外研究的目的是评估使用通过铣削、3D打印技术、选择性激光熔化（SLM）和电子束熔化（EBM）制造的CAD-CAM框架，由6颗种植体支持的上颌全牙弓固定修复体在咀嚼模拟前后的边缘适合性和螺丝松动扭矩。
采用铣削、SLM和EBM技术制造Ti-6Al-4V框架（n = 5），随后进行陶瓷贴面。通过扫描电子显微镜和激光扫描共聚焦显微镜评估框架的表面形貌。采用单因素方差分析（ANOVA）评估表面积。对标本在咀嚼模拟前后的因变量（边缘适合性和螺丝松动扭矩）进行进一步评估。进行双向重复测量ANOVA和Pearson相关性分析（α = 0.05）。
形貌分析表明，铣削组表面光滑（表面积：1.17±0.02 µm），区域规则，而增材制造组呈现树枝状轮廓，表面积更大（SLM：1.23±0.05 µm；EBM：1.21±0.03 µm；P < 0.05）。双向ANOVA发现，对于两个因变量，技术和时间之间没有交互作用（P > 0.05）。边缘适合性在制造技术或评估时间方面均未显示出进一步的显著差异。咀嚼模拟降低了螺丝松动扭矩（P = 0.032）。关于制造技术，与SLM相比，铣削导致更高的螺丝松动扭矩（P = 0.01）；然而，EBM与SLM或铣削之间未观察到差异（P > 0.05）。仅在合并的CAD-CAM（铣削、SLM和EBM）标本的基线时，观察到边缘适合性与螺丝松动扭矩之间存在中等相关性（P = 0.02）。
由铣削、SLM和EBM制造的6颗种植体支持的CAD-CAM全牙弓固定修复体的边缘适合性值低于可接受的误差限度。关于修复体螺丝松动扭矩，合并的铣削框架与SLM相比显示出更好的值。咀嚼模拟后，所有修复体的修复体螺丝稳定性均下降。
