Botelho Maria Paula Jacobucci, Isolan Cristina Pereira, Schwantz Júlia Kaster, Lopes Murilo Baena, Moraes Rafael Ratto de
Universidade Norte do Paraná, Londrina, PR, Brasil.
Universidade Federal de Pelotas, Faculdade de Odontologia, Pelotas, RS, Brasil.
J Appl Oral Sci. 2017 Sep-Oct;25(5):523-532. doi: 10.1590/1678-7757-2016-0627.
This study investigated whether increasing the concentration of acidic monomers in one-step adhesives would allow reducing their application time without interfering with the bonding ability to primary enamel and dentin.
Experimental one-step self-etch adhesives were formulated with 5 wt% (AD5), 20 wt% (AD20), or 35 wt% (AD35) acidic monomer. The adhesives were applied using rubbing motion for 5, 10, or 20 s. Bond strengths to primary enamel and dentin were tested under shear stress. A commercial etch-and-rinse adhesive (Single Bond 2; 3M ESPE) served as reference. Scanning electron microscopy was used to observe the morphology of bonded interfaces. Data were analysed at p<0.05.
In enamel, AD35 had higher bond strength when rubbed for at least 10 s, while application for 5 s generated lower bond strength. In dentin, increased acidic monomer improved bonding only for 20 s rubbing time. The etch-and-rinse adhesive yielded higher bond strength to enamel and similar bonding to dentin as compared with the self-etch adhesives. The adhesive layer was thicker and more irregular for the etch-and-rinse material, with no appreciable differences among the self-etch systems.
Overall, increasing the acidic monomer concentration only led to an increase in bond strength to enamel when the rubbing time was at least 10 s. In dentin, despite the increase in bond strength with longer rubbing times, the results favoured the experimental adhesives compared to the conventional adhesive. Reduced rubbing time of self-etch adhesives should be avoided in the clinical setup.
本研究调查了增加一步法粘结剂中酸性单体的浓度是否能在不影响与乳牙釉质和牙本质粘结能力的情况下缩短其应用时间。
配制含5 wt%（AD5）、20 wt%（AD20）或35 wt%（AD35）酸性单体的实验性一步自酸蚀粘结剂。采用摩擦动作涂抹粘结剂5、10或20秒。在剪切应力下测试与乳牙釉质和牙本质的粘结强度。一种市售的酸蚀冲洗粘结剂（Single Bond 2；3M ESPE）作为对照。使用扫描电子显微镜观察粘结界面的形态。数据在p<0.05水平进行分析。
在釉质中，AD35在摩擦至少10秒时具有较高的粘结强度，而涂抹5秒时粘结强度较低。在牙本质中，酸性单体增加仅在摩擦20秒时改善了粘结。与自酸蚀粘结剂相比，酸蚀冲洗粘结剂对釉质的粘结强度更高，对牙本质的粘结相似。酸蚀冲洗材料的粘结层更厚且更不规则，自酸蚀系统之间无明显差异。
总体而言，仅当摩擦时间至少为10秒时，增加酸性单体浓度才会导致与釉质的粘结强度增加。在牙本质中，尽管摩擦时间延长粘结强度增加，但与传统粘结剂相比，结果更有利于实验性粘结剂。在临床操作中应避免缩短自酸蚀粘结剂的摩擦时间。
