Leung K C, Chow T W, Woo E C, Clark R K
Faculty of Dentistry, University of Hong Kong, Hong Kong.
J Prosthet Dent. 1999 May;81(5):586-90. doi: 10.1016/s0022-3913(99)70214-3.
The efficacy of adhesive material is believed to be affected by the drying time allowed. However, there is no universal consensus on the drying time required for adhesive to achieve optimal bond strength for irreversible hydrocolloid impressions.
This study investigated the effect of drying time on the cleavage bond strength of irreversible hydrocolloid adhesive and determined optimal adhesive drying time.
In the cleavage test, the adhesive bond was stressed at the edge. An offset tensile force was applied to 1 side of the testing plates to split the bond. Cleavage testing plates were designed and machined in stainless steel. Adhesive material (Fix) was applied thinly to the plates and allowed to dry for 1, 3, 5, 7.5, 10, and 20 minutes before loading with an irreversible hydrocolloid (Blueprint). The irreversible hydrocolloid was then allowed to set for 5 minutes before testing. Twenty specimens were tested for each selected drying time. The force at failure was measured by an Instron machine with a crosshead speed of 50 mm/min applied to the edge of the bond. A nonadhesive group was included as a control.
The calculated cleavage bond strength at 1-minute drying (32 kPa) improved moderately up to 5-minute drying (37 kPa), but decreased on further drying. When compared with specimens in the nonadhesive group, cleavage bond strength was 3 times greater when the adhesive was applied and dried for 5 minutes.
Adhesive is effective in improving the cleavage bond strength of irreversible hydrocolloid to stainless steel, and drying of adhesive in excess of 5 minutes is not recommended.
人们认为粘结材料的功效受所允许的干燥时间影响。然而，对于不可逆水胶体印模材料而言，粘结剂要达到最佳粘结强度所需的干燥时间尚无普遍共识。
本研究调查干燥时间对不可逆水胶体粘结剂的抗劈裂粘结强度的影响，并确定最佳粘结剂干燥时间。
在劈裂试验中，粘结处边缘承受应力。向测试板的一侧施加偏置拉力以撕开粘结处。劈裂测试板采用不锈钢设计并加工而成。将粘结材料（Fix）薄薄地涂覆在测试板上，在加载不可逆水胶体（Blueprint）之前分别干燥1、3、5、7.5、10和20分钟。然后让不可逆水胶体凝固5分钟后进行测试。每个选定的干燥时间测试20个样本。通过英斯特朗材料试验机以50毫米/分钟的十字头速度对粘结处边缘施加力来测量破坏时的力。设置一个无粘结剂组作为对照。
1分钟干燥时计算得出的抗劈裂粘结强度（32千帕）在干燥至5分钟时适度提高（37千帕），但进一步干燥时强度下降。与无粘结剂组的样本相比，粘结剂涂覆并干燥5分钟时，抗劈裂粘结强度提高了两倍。
粘结剂可有效提高不可逆水胶体与不锈钢之间的抗劈裂粘结强度，不建议粘结剂干燥超过5分钟。
