Zhou Ying, Li Yong, Ma Xiao, Huang Yiqing, Wang Jiawei
Department of Prosthodontics, School and Hospital of Stomatology, Wuhan University, Wuhan, P.R.China.
J Adv Prosthodont. 2017 Apr;9(2):124-129. doi: 10.4047/jap.2017.9.2.124. Epub 2017 Apr 6.
This study evaluated the effect of span length on the adaptation of implant-supported cobalt chromium frameworks fabricated by three techniques.
Models with two solid abutment analogs at different inter-abutment distances were digitized using a laboratory scanner. Frameworks of two-, three-, and four-unit fixed prostheses were designed by a computer. Six dots with a diameter of 0.2 mm were preset on the surface of each framework. A total of 54 implant-supported cobalt chromium frameworks were fabricated by milling, selective laser melting (SLM), and cast techniques. The frameworks were scanned and exported as Stereolithography files. Distances between two dots in X, Y, and Z coordinates were measured in both the designed and fabricated frameworks. Marginal gaps between the framework and the abutments were also evaluated by impression replica method.
In terms of distance measurement, significant differences were found between three- and four-unit frameworks, as well as between two- and four-unit frameworks prepared by milling technique (<.05). Significant differences were also noted between two- and three-unit frameworks, as well as between two- and four-unit frameworks prepared by cast technique (<.05). The milling technique presented smaller differences than the SLM technique, and the SLM technique showed smaller differences than the cast technique at any unit prostheses (<.05). Evaluation with the impression replica method indicated significant differences among the span lengths for any fabrication method (<.05), as well as among the fabrication methods at any unit prostheses (<.05).
The adaptation of implant-supported cobalt chromium frameworks was affected by the span length and fabrication method.
本研究评估跨度长度对采用三种技术制作的种植体支持钴铬支架适配性的影响。
使用实验室扫描仪对在不同基牙间距处带有两个实心基牙代型的模型进行数字化处理。通过计算机设计两单位、三单位和四单位固定义齿的支架。在每个支架表面预先设置6个直径为0.2毫米的点。采用铣削、选择性激光熔化（SLM）和铸造技术共制作54个种植体支持的钴铬支架。对支架进行扫描并导出为立体光刻文件。在设计和制作的支架中测量X、Y和Z坐标上两点之间的距离。还通过印模复制法评估支架与基牙之间的边缘间隙。
在距离测量方面，铣削技术制作的三单位和四单位支架之间以及两单位和四单位支架之间存在显著差异（<.05）。铸造技术制作的两单位和三单位支架之间以及两单位和四单位支架之间也存在显著差异（<.05）。在任何单位义齿中，铣削技术的差异均小于SLM技术，SLM技术的差异小于铸造技术（<.05）。印模复制法评估表明，对于任何制作方法，跨度长度之间存在显著差异（<.05），在任何单位义齿中制作方法之间也存在显著差异（<.05）。
种植体支持钴铬支架的适配性受跨度长度和制作方法的影响。
