Wilson P R
School of Dental Science, University of Melbourne, VIC, Australia.
J Dent. 1996 Jul;24(4):269-73. doi: 10.1016/0300-5712(95)00074-7.
The marginal adaptation of full coverage restorations is adversely affected by the introduction of luting agents of various minimum film thicknesses during the cementation process. The increase in the marginal opening may have long-term detrimental effects on the health of both pulpal and periodontal tissues. The purpose of this study was to determine the effects of varying seating forces (2.5, 12.5, 25 N), venting, and cement types on post-cementation marginal elevation in cast crowns.
A standardized cement space of 40 microns was provided between a machined gold crown and a stainless steel die. An occlusal vent was placed that could be opened or closed. The post-cementation crown elevation was measured, following the use of two commercially available capsulated dental cements (Phosphacap, and Ketac-cem Applicap).
The results indicate that only the combination of Ketac-Cem Applicap and crown venting produced post-cementation crown elevation of less than 20 microns when 12.5 N seating force was used. Higher forces (25 N) and venting were required for comparable seating when using Phosphacap (19 microns).
The amount of force required to allow maximum seating of cast crowns appears to be cement specific, and is reduced by effective venting procedures.
在粘固过程中，各种最小膜厚度的粘固剂的引入会对全冠修复体的边缘适合性产生不利影响。边缘开口的增加可能对牙髓和牙周组织的健康产生长期有害影响。本研究的目的是确定不同就位力（2.5、12.5、25牛）、排气和粘固剂类型对铸造全冠粘固后边缘高度的影响。
在机械加工的金冠和不锈钢代型之间提供40微米的标准化粘固剂空间。设置一个可以打开或关闭的咬合排气孔。在使用两种市售的胶囊型牙科粘固剂（磷酸锌粘固剂和玻璃离子粘固剂）后，测量粘固后全冠的高度。
结果表明，当使用12.5牛的就位力时，只有玻璃离子粘固剂和全冠排气的组合产生的粘固后全冠高度小于20微米。使用磷酸锌粘固剂时，要达到类似的就位效果则需要更大的力（25牛）和排气。
使铸造全冠达到最大就位所需的力的大小似乎因粘固剂而异，有效的排气程序可降低所需的力。
