Salamoni Sinhori Bruna, Vieira Luiz Clovis Cardoso, Baratieri Luiz Narciso
Professor Graduate Curses Operative Dentistry, University of Caxias do Sul, Caxias do Sul, RS, Brazil.
Professor, Undergraduate and Graduate Courses Operative Dentistry, Federal University of Santa Catarina, Florianopolis, SC, Brazil.
Int J Biomater. 2019 Jan 1;2019:7307649. doi: 10.1155/2019/7307649. eCollection 2019.
The aim of this study was to evaluate whether the compressive strength of lithium dissilicate ceramic inlays is influenced by the substrate (dentin or composite resin build-up) and to compare it to nonrestored teeth. Thirty freshly extracted human maxillary third molars were selected and randomly ascribed to three groups (n=10). Standardized Class II MOD preparations were made (bucco-palatal width = 2/3 of the intercuspal width and 2/3 of the width at the tooth equator for the proximal boxes), varying the extension of the preparations (Group 2: preparation limited to tooth structure; Group 3: pulpal floor of the preparation rebuilt with composite resin, IPS Empress Direct, restored with lithium dissilicate CAD/CAM ceramic inlays (e.max CAD) and cemented with a resin cement (Variolink II)). All groups were subjected to compressive strength test (1mm/min crosshead speed). The results showed that the fracture strength of G1 (control group) was significantly higher than G2 and G3, while within these groups there were no statistically significant differences. Both groups restored with lithium dissilicate restorations did not reach the fracture strength of the sound teeth but were statistically equivalent and sufficient to withstand physiologic masticatory forces.
本研究的目的是评估二硅酸锂陶瓷嵌体的抗压强度是否受基底（牙本质或复合树脂堆塑）影响，并将其与未修复牙齿进行比较。选取30颗新鲜拔除的人类上颌第三磨牙，随机分为三组（n = 10）。制作标准化的II类MOD洞形（颊舌径 = 牙尖间宽度的2/3，近中盒在牙赤道处宽度的2/3），改变洞形的扩展范围（第2组：洞形局限于牙体结构；第3组：用复合树脂（IPS Empress Direct）重建洞形的髓室底，用二硅酸锂CAD/CAM陶瓷嵌体（e.max CAD）修复并用树脂水门汀（Variolink II）粘结）。所有组均进行抗压强度测试（十字头速度1mm/min）。结果显示，G1组（对照组）的断裂强度显著高于G2组和G3组，而这两组之间无统计学显著差异。两组用二硅酸锂修复体修复的牙齿均未达到完好牙齿的断裂强度，但在统计学上相当，足以承受生理咀嚼力。
