Browning William D, Nelson Stephen K, Cibirka Roman, Myers Michael L
Department of Oral Rehabilitation, Medical College of Georgia, School of Dentistry, 1120 15th Street, Augusta, Georgia 30912-1260, USA.
Quintessence Int. 2002 Feb;33(2):95-100.
The purpose of this study was to compare the retentive strengths of resin, glass-ionomer, and zinc phosphate cements under adverse conditions.
Thirty extracted teeth were mounted and prepared in their long axis. The axial wall height was 3 mm and the convergence angle was 28 degrees. These conditions increased the role of the cement and decreased the role of the preparation in providing retention of the casting. The axial surface area was determined. Copings were fabricated with a ring aligned in the long axis to facilitate removal of the crown. They were cemented with a resin cement, a glass-ionomer cement, or a zinc phosphate cement. A block randomization scheme was used to assign cements so that the mean surface areas of the teeth were equivalent in all groups. The copings were loaded in tension, and the amount of force required to remove the coping was recorded. The stress required to remove the coping was calculated.
The mean stress required to remove the copings was 9.4, 5.0, and 3.1 MPa for the resin, glass-ionomer, and zinc phosphate cements, respectively.
The resin cement group was significantly stronger than both the glass-ionomer cement and the zinc phosphate cement groups. The glass-ionomer cement was significantly stronger than the zinc phosphate cement.
本研究旨在比较在不利条件下树脂、玻璃离子水门汀和磷酸锌水门汀的固位强度。
选取30颗离体牙，沿其长轴进行预备。轴壁高度为3mm，聚合角为28度。这些条件增加了水门汀的作用，同时减少了预备体在提供铸件固位方面的作用。测定轴面面积。制作带有沿长轴排列的环的冠内修复体，以便于去除全冠。分别用树脂水门汀、玻璃离子水门汀或磷酸锌水门汀进行粘结。采用区组随机化方案分配水门汀，以使所有组中牙齿的平均表面积相等。对冠内修复体施加拉力，并记录去除冠内修复体所需的力的大小。计算去除冠内修复体所需的应力。
树脂水门汀、玻璃离子水门汀和磷酸锌水门汀去除冠内修复体所需的平均应力分别为9.4MPa、5.0MPa和3.1MPa。
树脂水门汀组显著强于玻璃离子水门汀组和磷酸锌水门汀组。玻璃离子水门汀显著强于磷酸锌水门汀。
