Removal Partial Denture Prosthodontics, Department of Masticatory Function Rehabilitation, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
Dent Mater J. 2011;30(5):635-41. doi: 10.4012/dmj.2011-006. Epub 2011 Sep 23.
This study evaluated the effect of surface roughness and tapered angle of cone crowns on retentive force (RF). Cone crowns from Ti-6Al-7Nb alloy with a tapered angle of 4, 5, or 6° were fabricated using a milling machine and a finishing machine to produce a smooth surface. Cone crowns of 6° with a rough surface were also prepared. The RF during 1,000 cycles of insertion/separation was recorded. The first RF of the 6° cone crowns was 24.2-27.7 N, and the surface roughness was not significant. The RF of all specimens decreased at 100 cycles, then those of inner and outer crowns with the same roughness remained unchanged, but those of different roughnesses increased with number of cycles. The RF of cone crowns with a smaller tapered angle was significantly greater than with a larger angle at any measured cycles.
本研究评估了牙冠表面粗糙度和锥度角对固位力（RF）的影响。使用铣床和精磨机制造具有 4°、5°或 6°锥度角的 Ti-6Al-7Nb 合金牙冠，以产生光滑的表面。还制备了具有粗糙表面的 6°锥度牙冠。记录了插入/分离 1000 次循环期间的 RF。6°牙冠的初始 RF 为 24.2-27.7 N，表面粗糙度不显著。所有试件的 RF 在 100 次循环时下降，然后具有相同粗糙度的内冠和外冠的 RF 保持不变，但具有不同粗糙度的 RF 随循环次数的增加而增加。在任何测量的循环次数下，具有较小锥度角的牙冠的 RF 明显大于具有较大锥度角的牙冠。
