Lin Jie, Matinlinna Jukka Pekka, Shinya Akikazu, Botelho Michael George, Zheng Zhiqiang
Department of VIP Dental Service, School and Hospital of Stomatology, Fujian Medical University, 246 Yangqiao Zhong Road, Fuzhou, 350002, Fujian, People's Republic of China.
Department of Crown and Bridge, The Nippon Dental University School of Life Dentistry at Tokyo, 1-9-20 Fujimi, Chiyoda-ku, Tokyo, 102-8159, Japan.
Odontology. 2018 Apr;106(2):215-222. doi: 10.1007/s10266-017-0320-7. Epub 2017 Dec 14.
The purpose of this study was to compare the fracture resistance, mode of fracture, and stress distribution of endodontically treated teeth prepared with three different fiber post lengths and two different abutment heights, using both experimental and finite element (FE) approaches. Forty-eight human maxillary premolars with two roots were selected and endodontically treated. The teeth were randomly distributed into six equally sized groups (n = 8) with different combinations of post lengths (7.5, 11, and 15 mm) and abutment heights (3 and 5 mm). All the teeth restored with glass fiber post (Rely X Fiber Post, 3M ESPE, USA) and a full zirconia crown. All the specimens were thermocycled and then loaded to failure at an oblique angle of 135°. Statistical analysis was performed for the effects of post length and abutment height on failure loads using ANOVA and Tukey's honestly significant difference test. In addition, corresponding FE models of a premolar restored with a glass fiber post were developed to examine mechanical responses. The factor of post length (P < 0.01) had a significant effect on failure load. The abutment height (P > 0.05) did not have a significant effect on failure load. The highest mean fracture resistance was recorded for the 15 mm post length and 5 mm abutment height test group, which was significantly more resistant to fracture than the 7.5 mm post and 5 mm abutment height group (P < 0.05). The FE analysis showed the peak compression and tension stress values of 7.5 mm post length were higher than that of 11 and 15 mm post length. The stress value of remaining tooth decreased as the post length was increased. Within the limitations of this experimental and FE analysis study, increasing the post length inside the root of endodontically treated premolar teeth restored with glass-fiber posts increase the fracture resistance to non-axial forces. Failure mode is more favorable with reduced abutment heights.
本研究的目的是采用实验和有限元（FE）方法，比较用三种不同纤维桩长度和两种不同基台高度制备的根管治疗牙的抗折性、骨折模式和应力分布。选择48颗有两个牙根的人上颌前磨牙并进行根管治疗。将牙齿随机分为六个大小相等的组（n = 8），每组具有不同的桩长度（7.5、11和15 mm）和基台高度（3和5 mm）组合。所有牙齿均用玻璃纤维桩（Rely X Fiber Post，3M ESPE，美国）和全锆冠修复。所有标本均进行热循环，然后以135°的倾斜角度加载至破坏。使用方差分析和Tukey真实显著性差异检验对桩长度和基台高度对破坏载荷的影响进行统计分析。此外，还建立了用玻璃纤维桩修复的前磨牙的相应有限元模型，以检查力学响应。桩长度因素（P < 0.01）对破坏载荷有显著影响。基台高度（P > 0.05）对破坏载荷没有显著影响。15 mm桩长度和5 mm基台高度测试组的平均抗折性最高，其抗折性明显高于7.5 mm桩和5 mm基台高度组（P < 0.05）。有限元分析表明，7.5 mm桩长度的峰值压缩和拉伸应力值高于11和15 mm桩长度。随着桩长度的增加，剩余牙齿的应力值降低。在本实验和有限元分析研究的范围内，增加用玻璃纤维桩修复的根管治疗前磨牙牙根内的桩长度可提高对非轴向力的抗折性。基台高度降低时，骨折模式更有利。
