Brendeke Johannes, Ozcan Mutlu
University Medical Center Groningen, University of Groningen, Department of Dentistry and Dental Hygiene, Groningen, The Netherlands.
J Adhes Dent. 2007 Aug;9(4):399-406.
This study evaluated the effect of different physicochemical aging methods and surface conditioning techniques on the repair bond strength of composite. It was hypothesized that the aging conditions would decrease the repair bond strength and surface conditioning methods would perform similarly for the repair of resin composites.
Disk-shaped resin composite specimens (Clearfil Photo Bright, Kuraray) were randomly assigned to one of the three aging conditions (N=120, n = 12/per group): (1) immersion in deionized water (37 degrees C, 1 week), (2) immersion in citric acid (pH: 3.0, 1 week), (3) boiling in water (8 h), (4) thermocycling (5000 times, 5 degrees C to 55 degreesC), (5) immersion in water (37 degrees C, 2 months). After aging procedures, the specimens were subjected to one of the following surface conditioning methods: (1) chairside silica coating (30-microm SiOx) (CoJet, 3M ESPE) + silane (ESPE-Sil) (SC method), (2) silane (Clearfil SE Bond Primer and Clearfil Porcelain Bond Activator) + bonding agent (Clearfil SE Bond) (SB method). The fresh and aged composite surfaces were also examined using SEM (n=6, 1/group). Resin composite (Quadrant Anterior Shine) was bonded to the conditioned substrates using polyethylene molds and then light polymerized. Shear force was applied to the adhesive interface in a universal testing machine (1 mm/min). The failure types were categorized as: (A) cohesive in the substrate, (B) adhesive at the interface, or C) cohesive in the adherend. Bond strength values were statistically analyzed using two-way ANOVA and Tukey's test (alpha < 0.05).
A significant influence of the conditioning method (p < 0.0001) and aging method was observed (p < 0.01) (two-way ANOVA, Tukey-Kramer). The SC method showed significantly higher bond values (7.8 +/- 1.2 to 11.6 +/- 5 MPa) than those of SB method (4.6 +/- 2.3 to 7.6 +/- 3.9 MPa) in all groups (p < 0.0001). While the SC method showed 96% cohesive (A type), the SB method demonstrated 92% adhesive failures (B type). SEM images showed distinct pattern of microcracks in the boiled specimens and filler dissolution with disorganized matrix resin in the other aged specimens. Aging the composite substrates through water storage for 2 months produced significantly lower bond strengths than those of water or acid storage for 1 week (p = 0.011).
Chairside silica coating and silanization provided the highest bond strength values with almost exclusively cohesive failures on aged composites. Aging methods showed significant differences on the composite-composite repair strength.
本研究评估了不同物理化学老化方法和表面处理技术对复合材料修复粘结强度的影响。研究假设老化条件会降低修复粘结强度，且表面处理方法在修复树脂复合材料时表现相似。
将圆盘状树脂复合材料试件（可乐丽菲露光固化复合树脂）随机分为三种老化条件之一（N = 120，每组n = 12）：（1）浸入去离子水中（37℃，1周）；（2）浸入柠檬酸中（pH：3.0，1周）；（3）水煮（8小时）；（4）热循环（5000次，5℃至55℃）；（5）浸入水中（37℃，2个月）。老化处理后，试件采用以下表面处理方法之一：（1）椅旁二氧化硅涂层（30微米SiOx）（CoJet，3M ESPE）+硅烷（ESPE-Sil）（SC法）；（2）硅烷（可乐丽SE粘结剂底涂剂和可乐丽瓷粘结活化剂）+粘结剂（可乐丽SE粘结剂）（SB法）。还使用扫描电子显微镜对新鲜和老化的复合材料表面进行了检查（每组n = 6）。使用聚乙烯模具将树脂复合材料（象限前牙光泽型）粘结到处理过的基底上，然后进行光固化。在万能试验机中以1毫米/分钟的速度对粘结界面施加剪切力。失效类型分为：（A）基底内聚性破坏；（B）界面处粘结性破坏；（C）被粘物内聚性破坏。粘结强度值采用双向方差分析和Tukey检验进行统计学分析（α < 0.05）。
观察到处理方法（p < 0.0001）和老化方法有显著影响（p < 0.01）（双向方差分析，Tukey-Kramer检验）。在所有组中，SC法显示出的粘结值（7.8±1.2至11.6±5兆帕）显著高于SB法（4.6±2.3至7.6±3.9兆帕）（p < 0.0001）。SC法显示96%为内聚性破坏（A类），而SB法显示92%为粘结性破坏（B类）。扫描电子显微镜图像显示，水煮试件中有明显的微裂纹模式，其他老化试件中有填料溶解且基体树脂无序排列。将复合材料基底在水中储存2个月进行老化，其粘结强度显著低于在水中或酸中储存1周的情况（p = 0.011）。
椅旁二氧化硅涂层和硅烷化处理提供了最高的粘结强度值，老化复合材料上几乎均为内聚性破坏。老化方法对复合材料-复合材料修复强度有显著差异。
