摘要
背景：经根管治疗的牙齿更易发生骨折，通常需要持久的修复解决方案。内冠提供了替代传统桩核系统的保守选择。本体外研究比较了铣削氧化锆和3D打印树脂内冠的抗折强度和失效行为。
材料与方法：将18颗离体人磨牙进行根管治疗并标准化，然后按照统一设计（2mm咬合面减径，4mm冠内延伸）制备内冠修复体。标本随机分配接受计算机辅助设计/制造（CAD/CAM）铣削氧化锆（ZR）或基于VarseoSmile Crown Plus（VS）的3D打印树脂内冠（每组n=9）。使用口内扫描仪捕获预备体，使用CAD软件设计修复体并通过相应工作流程制造，所有单元均用双固化自粘接树脂水门汀粘固。经过受控储存后，标本承受压缩载荷直至破坏；记录最大抗折强度，并根据损伤是否局限于修复体或涉及牙体组织对失效模式进行分类。数据经过正态性检验，并在p<0.05的显著性水平下使用Welch校正的独立样本t检验进行分析。
结果：统计分析显示两组间抗折强度差异极显著（p<0.001），ZR表现出更高的强度（3,615.36±792.74 N），而VS为（1,395.09±149.24 N）。然而，8/9的ZR标本（88.9%）涉及牙体组织损伤，其中5个标本（占总组的55.6%）被归类为复杂/破坏性失效，而VS失效简单且局限于修复体，在5/9标本中（55.6%），表明其失效模式较不严重且可能具有可修复性。
结论：ZR组显示出显著更高的抗折强度，但失效更常涉及牙体组织。VS组强度较低，但更高比例的简单、可能可修复的断裂局限于修复体，突出了最大承载能力与可修复性之间的权衡。在本体外研究的局限性内，这些发现支持在优先考虑保留牙体的内冠设计和数字工作流程效率，且希望出现较不严重失效行为的特定临床情况下使用3D打印树脂内冠。
原文摘要
BACKGROUND: Endodontically treated teeth are more prone to fracture and often require durable restorative solutions. Endocrowns offer a conservative alternative to conventional post-and-core systems. This in vitro study compared the fracture load and failure behavior of milled zirconia and 3D-printed resin endocrowns.
MATERIALS AND METHODS: Eighteen extracted human molars were endodontically treated and standardized, then prepared for endocrown restorations using a uniform design (two mm occlusal reduction with a four mm intracoronal extension). Specimens were randomly assigned to receive either Computer-Aided Design (CAD)/ Computer-Aided Manufacturing (CAM) milled zirconia (ZR) or 3D-printed resin-based endocrowns fabricated from VarseoSmile Crown Plus (VS) (n = 9 per group). Preparations were digitally captured with an intraoral scanner, restorations were designed using CAD software and fabricated by the respective workflows, and all units were cemented with dual cure self-adhesive resin cement. After controlled storage, specimens underwent compressive loading to failure; maximum fracture loads were recorded, and failure modes were categorized according to whether damage was confined to the restoration or involved the tooth structure. Data were assessed for normality and analyzed using an independent samples t-test with Welch correction at a significance level of p < 0.05.
RESULTS: Statistical analysis revealed a highly significant difference in fracture load between the two groups (p < 0.001), with ZR demonstrating higher strength (3,615.36 ± 792.74 N) compared with VS (1,395.09 ± 149.24 N). However, tooth structure involvement occurred in 8/9 ZR specimens (88.9%), of these, five specimens (55.6% of the total group) were classified as complex/destructive failure, whereas VS failures were simple and confined to the restoration in 5/9 specimens (55.6%), indicating a less severe and potentially repairable failure pattern.
CONCLUSION: The ZR group showed substantially higher fracture load, but failures more frequently involved tooth structure. VS group exhibited lower strength, yet a higher proportion of simple, potentially repairable fractures confined to the restoration, highlighting a tradeoff between maximum load capacity and repairability. Within the limitations of this in vitro study, these findings support the use of 3D-printed resin endocrowns in selected clinical situations where a tooth preserving endocrown design and digital workflow efficiency are prioritized, and where less severe failure behavior is desirable.
出处
PeerJ 2026;14:e21602. DOI: 10.7717/peerj.21602.
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