Abstract：
OBJECTIVE: This in vitro study aims to compare the fracture resistance of three CAD/CAM materials used in endocrown restoration of interproximal defects in maxillary premolars.
METHODS: 45 maxillary premolars extracted as part of orthodontic treatment were included. Following standardized root canal treatment, all teeth were prepared into Mesial-Occlusal (MO) cavity types. The samples were then randomly divided into three groups: LD [repaired with lithium disilicate glass ceramics (IPS e.max CAD)], VE [treated with polymer-infiltrated ceramics (Vita Enamic)], and LU [repaired with resin-based nanoceramics (Lava Ultimate)]. Axial static loading was applied using a universal testing machine at 1 mm/min until fracture, and fracture resistance and failure modes were recorded.
RESULTS: Regarding Fracture Resistance Values (FRVs), the LD group exhibited significantly higher values than the other two groups, VE (P = 0.028) and LU (P = 0.005), which showed no significant difference (P = 0.778). On the other hand, regarding failure modes, the LD group had a higher prevalence of irreparable fractures compared to the other two groups, VE (P < 0.001) and LU (P < 0.001), which showed no significant difference.
CONCLUSIONS: Although lithium disilicate glass ceramics exhibited higher FRVs, they had a lower repair probability. In contrast, polymer-infiltrated ceramics and resin-based nanoceramics contributed to tooth structure preservation.
CONCLUSIONS: For maxillary premolars with interproximal defects following root canal treatment, resin ceramic composites are recommended for restoration to enhance abutment teeth protection.
METHODS: 45 maxillary premolars extracted as part of orthodontic treatment were included. Following standardized root canal treatment, all teeth were prepared into Mesial-Occlusal (MO) cavity types. The samples were then randomly divided into three groups: LD [repaired with lithium disilicate glass ceramics (IPS e.max CAD)], VE [treated with polymer-infiltrated ceramics (Vita Enamic)], and LU [repaired with resin-based nanoceramics (Lava Ultimate)]. Axial static loading was applied using a universal testing machine at 1 mm/min until fracture, and fracture resistance and failure modes were recorded.
RESULTS: Regarding Fracture Resistance Values (FRVs), the LD group exhibited significantly higher values than the other two groups, VE (P = 0.028) and LU (P = 0.005), which showed no significant difference (P = 0.778). On the other hand, regarding failure modes, the LD group had a higher prevalence of irreparable fractures compared to the other two groups, VE (P < 0.001) and LU (P < 0.001), which showed no significant difference.
CONCLUSIONS: Although lithium disilicate glass ceramics exhibited higher FRVs, they had a lower repair probability. In contrast, polymer-infiltrated ceramics and resin-based nanoceramics contributed to tooth structure preservation.
CONCLUSIONS: For maxillary premolars with interproximal defects following root canal treatment, resin ceramic composites are recommended for restoration to enhance abutment teeth protection.
摘要：
目的：这项体外研究旨在比较三种CAD/CAM材料在上颌前磨牙邻间缺损的内生修复中的抗骨折性。
方法：包括45颗上颌前磨牙作为正畸治疗的一部分。规范根管治疗后，所有牙齿都准备成内咬合（MO）腔类型。然后将样品随机分为三组：LD[用二硅酸锂玻璃陶瓷（IPSe.maxCAD）修复]，VE[用聚合物渗透陶瓷(VitaEnamic)处理]，和LU[用树脂基纳米陶瓷修复(熔岩极限)]。使用万能试验机以1mm/min的速度施加轴向静载荷，直至断裂，记录断裂阻力和失效模式。
结果：关于断裂阻力值（FRV），LD组表现出明显高于其他两组，VE（P=0.028）和LU（P=0.005），差异无统计学意义(P=0.778)。另一方面,关于故障模式，与其他两组相比，LD组的不可修复骨折患病率更高，VE（P<0.001）和LU（P<0.001），没有显着差异。
结论：尽管二硅酸锂玻璃陶瓷表现出更高的FRV，他们的修复概率较低。相比之下,聚合物渗透陶瓷和树脂基纳米陶瓷有助于保持牙齿结构。
结论：对于根管治疗后有牙间缺损的上颌前磨牙，树脂陶瓷复合材料被推荐用于修复，以增强基牙保护。
方法：包括45颗上颌前磨牙作为正畸治疗的一部分。规范根管治疗后，所有牙齿都准备成内咬合（MO）腔类型。然后将样品随机分为三组：LD[用二硅酸锂玻璃陶瓷（IPSe.maxCAD）修复]，VE[用聚合物渗透陶瓷(VitaEnamic)处理]，和LU[用树脂基纳米陶瓷修复(熔岩极限)]。使用万能试验机以1mm/min的速度施加轴向静载荷，直至断裂，记录断裂阻力和失效模式。
结果：关于断裂阻力值（FRV），LD组表现出明显高于其他两组，VE（P=0.028）和LU（P=0.005），差异无统计学意义(P=0.778)。另一方面,关于故障模式，与其他两组相比，LD组的不可修复骨折患病率更高，VE（P<0.001）和LU（P<0.001），没有显着差异。
结论：尽管二硅酸锂玻璃陶瓷表现出更高的FRV，他们的修复概率较低。相比之下,聚合物渗透陶瓷和树脂基纳米陶瓷有助于保持牙齿结构。
结论：对于根管治疗后有牙间缺损的上颌前磨牙，树脂陶瓷复合材料被推荐用于修复，以增强基牙保护。
