两种牙本质粘接剂粘接界面的扫描电镜研究

Studies on Bonding Interfaces of Two Dentin Adhesives by Scanning Electron Microscopy

目的 研究两种新型牙本质粘接剂 Prim e & Bond○RNT(PBNT)和 Prim e one Mirage TM(P- One)粘接界面的超微结构和粘接机理。方法 选用 15颗拔出的无龋人类磨牙 ,按牙本质粘接剂微拉伸强度测试标本预备法 ,将各试验牙预备成牙冠中部有一深约 5 m m的小槽隔开的两个粘接面 ,以分别接受两种粘接剂处理。粘接后的标本浸于 37℃的蒸馏水中 2 4 h后分成两组 : 组 (5颗牙 )直接进行扫描电镜观察和粘接强度测试 ; 组 (10颗牙 )则在扫描电镜观察和粘接强度测试前行 5℃和 5 5℃的冷热循环 2 4 0 0次。将两组牙齿标本修整、片切成厚约 0 .5 mm的哑铃状系列微型薄片 ,供扫描电镜观察和拉伸测试。结果 PBNT和 P- One各自的粘接界面均可见厚约 3～ 5μm的混合层和伸入牙本质小管内的树脂突及彼此交织成网的树脂突侧支。此两种粘接剂以及它们各自是否经过温度循环 ,粘接界面的 SEM形貌均无明显差异。结论 PBNT和 P- One均可产生良好的树脂浸润 。

Objective The purpose of this study was to investigate the microstructure and bonding mechanism of bonding interfaces of two current one bottle dentin bond systems(Prime & Bond ○R NT, PBNT;Prime one Mirage TM , P One). Methods Fifteen extracted, caries free human molars were prepared according to a modified method used for microtensile bond strength measurement. Each crown was divided into nearly equal halves with a 5 mm deep slot for accepting treatment of the two dentin bond systems, respectively. After 24 h storage in distilled water at 37℃, the bonded teeth were subjected to two treatments: 5 teeth were observed by and tested for microtensile bond strengths without further treatment and 10 teeth were thermocycled(2400 cycles, between 5℃ and 55℃) prior to SEM observation and bond strength testing. Hour glass shaped microspecimens with a thickness of approximately 0.5 mm were cut from each tooth and used for SEM observation and microtensile bond strength measurement. Results A typical resin infiltrated zone (hybrid layer) with a thickness of 3~5 μm and well formed cone shaped resin tags that penetrated the dentinal tubules were clearly observed at the resin dentin interfaces in the two bond systems. There were multiple lateral branches of tubular resin tags that interconnected to form a micronetwork of resin. No evident differences in SEM images between the two bond systems as well as between thermocycling and without thermocycling in each bond system were found. Conclusion PBNT and P One provided good resin infiltration, producing a three dimensional interlocking micronetwork of resin tags in the dentin tubules with multiple lateral branches that penetrate the intertubular dentin, which positively influenced the adhesion between dentin and the two bond systems.