Mohammadi Reza, Alkurt Kaplan Sinem, Harmankaya Abdulkadir, Gönder Hakan Yasin
Faculty of Dentistry, Necmettin Erbakan University, Konya 42090, Turkey.
Department of Oral and Maxillofacial Diseases, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland.
Materials (Basel). 2025 Aug 20;18(16):3888. doi: 10.3390/ma18163888.
This study aimed to compare the stress distribution and fracture resistance of dental tissues and restorative materials with varying adhesive layer thicknesses and different restorative materials. A caries-free mandibular first molar (tooth #36) was scanned using CBCT. The scanned files were processed in Mimics 12 software for segmentation of enamel, dentin, and pulp tissues and then exported to STP format. Cavity preparations (DO, MO, MOD, and O) were designed in SolidWorks 2023. Bulk-fill composite, conventional composite, and hybrid composite were used for restorations with adhesive layers of 10, 15, and 20 μm thick. Stress distribution and fracture resistance were analyzed using 3D finite element analysis. The highest stress values in enamel, dentin, and adhesive material were observed in models restored with bulk-fill composite, while the highest stress values within the restoration were found in models restored with hybrid composite. As the adhesive layer thickness decreased, stress accumulation within the restorative material increased. Enamel fractures occurred first in models with bulk-fill composite. Among restorative materials, fractures initiated first in models restored with hybrid composite, while the latest fracture onset was observed in models with bulk-fill composite. Restorative materials with low Young's modulus cause excessive stress accumulation in enamel and dentin, leading to early fracture of these tissues. In contrast, materials with a high Young's modulus transfer more stress to the restoration, causing premature fracture of the restorative material.
本研究旨在比较不同粘结层厚度和不同修复材料的牙体组织及修复材料的应力分布和抗折性能。使用锥形束计算机断层扫描（CBCT）对一颗无龋的下颌第一磨牙（36号牙）进行扫描。扫描文件在Mimics 12软件中进行处理，以分割釉质、牙本质和牙髓组织，然后导出为STP格式。在SolidWorks 2023中设计洞形预备（近中邻面洞、远中邻面洞、近中邻面远中洞和单面洞）。使用大块充填复合树脂、传统复合树脂和混合型复合树脂进行修复，粘结层厚度分别为10、15和20μm。采用三维有限元分析方法分析应力分布和抗折性能。在使用大块充填复合树脂修复的模型中，釉质、牙本质和粘结材料中的应力值最高，而在使用混合型复合树脂修复的模型中，修复体内的应力值最高。随着粘结层厚度的减小，修复材料内的应力积累增加。在使用大块充填复合树脂的模型中，釉质首先发生骨折。在修复材料中，骨折首先在使用混合型复合树脂修复的模型中出现，而在使用大块充填复合树脂的模型中骨折发生最晚。杨氏模量低的修复材料会导致釉质和牙本质中应力过度积累，导致这些组织早期骨折。相比之下，杨氏模量高的材料会将更多应力传递到修复体上，导致修复材料过早骨折。
