Objective: To compare shear bond strength (SBS) between two types of silicone soft liner and polymethyl methacrylate (PMMA) under the condition of heat curing and room temperature curing.
Methods: A total of 48 PMMA specimens (50 mm x 10 mm x 3 mm) were made by water-bath heating method, and randomly divided into four groups. By using Ufi Gel P (UGP) as soft liner material, group A1 was prepared under heat curing, and group A2 was prepared under room temperature curing. To form the other two groups, Silagum-Comfort (SLC) as soft-liner material was used. Group B1 was prepared under heat curing, and group B2 was prepared under room temperature curing. Shear bond strength (SBS) was tested by using the electronic universal testing machine. The adhesives layer and surface of silastic and PMMA were observed by optical microscope and scanning electron microscopy (SEM).
Results: The SBS of groups A1, A2, B1, B2 were (2.39 +/- 0.24), (1.74 +/- 0.27), (3.09 +/- 0.26), and (2.21 +/- 0.29) MPa, respectively. Significant differences were found between A1 and A2, B1 and B2, A1 and B1, and A2 and B2 (P < 0.05). Optical microscope showed numerous bubbles in the cured UGP, and no air bubbles in the SLC. The surface of PMMA was rough. SEM images showed that each group had continual consistent adhesive interface and a whisker hump on the adhesive layer of A2 and B2.
Conclusion: The SBS ofUGP, SLC, and PMMA achieved minimum clinical standard of 0.44 MPa. The SBS of UGP and PMMA were higher than that of SLC and PMMA. The polymerization method of heat curing was higher than room temperature curing.
目的: 比较两种软衬硅橡胶在热固化和室温固化条件下，其与聚甲基丙烯酸甲酯（PMMA）的粘接强度。
方法: 水浴加热法制得50 mm×10 mm×3 mm PMMA试片48片，并随机分成4组。以Ufi Gel P（UGP）为软衬材料，制作热固化组（A1组）和室温固化组（A2组）试件。以Silagum-Comfort（SLC）为软衬材料，制作热固化组（B1组）和室温固化组（B2组）试件。每组试件各6个。采用电子万能材料试验机对试件进行抗剪切强度测试，并在光学显微镜、扫描电子显微镜（SEM）下观察粘接界面、固化后软衬硅橡胶和打磨后PMMA的表面形态。
结果: A1、A2、B1、B2组的抗剪切强度分别为（2.39±0.24）、（1.74±0.27）、（3.09±0.26）、（2.21±0.29）MPa。A1与A2、B1与B2、A1与B1、A2与B2组间的差异均有统计学意义（P<0.05）。光学显微镜和SEM下可见，固化后UGP体部有大量的气泡，SLC无气泡；PMMA表面较为粗糙；各组粘接界面均连续、均匀、密实，A2、B2组粘接界面有须状微突起物。
结论: UGP、SLC与PMMA的抗剪切强度均达到了0.44 MPa的临床最低使用标准；UGP与PMMA的抗剪切强度高于SLC与PMMA；热固化方式获得的抗剪切强度高于室温固化方式。