Leung Y, Morris M D
Department of Chemistry, University of Michigan, Ann Arbor, USA.
Dent Mater. 1995 May;11(3):191-5. doi: 10.1016/0109-5641(95)80017-4.
The goal of this investigation was to use Raman spectroscopy to study the chemical interactions between 4-methacryloxyethyltrimellitic acid (4-MET), a hydrolized form of 4-methacryloxyethyltrimellitate anhydride (4-META) and powdered substrates such as bovine enamel powder and synthetic carbonate-containing apatite.
Powdered samples were prepared by immersing them in 4-MET/methylmethacrylate (MMA) solution for 15 min, 3 h and 24 h. They were then dried for spectroscopy. An experimental Raman microprobe equipped with a cryogenically-cooled camera was employed to acquire spectra of the samples.
Spectra of samples wetted for 24 h strongly indicate that there is strong ionic interaction between Ca2+ ions on the powdered sample surface and 4-MET. Spectra of the 15-min samples, however, suggest only some degree of hydrogen bonding. The spectrum of the 3-h 4-MET/enamel powder sample showed features intermediate between the two.
Results presented in this paper show that salt formation between 4-MET and dental substrates is not likely to be instantaneous. On the contrary, the rate of such reaction is probably too slow relative to that of polymerization of the co-monomers to be important under clinical conditions. The function of the 4-MET in the 4-MET/MMA resin system appears, therefore to be wetting the tooth surface through hydrogen bonding, which then allows MMA monomers to diffuse and penetrate deeper through the surfaces. The primary bonding mechanism of this system is more likely due to a micro-mechanical locking mechanism.
本研究的目的是利用拉曼光谱研究4-甲基丙烯酰氧乙基偏苯三酸（4-MET），即4-甲基丙烯酰氧乙基偏苯三酸酐（4-META）的水解形式与粉末状底物（如牛牙釉质粉和含合成碳酸盐的磷灰石）之间的化学相互作用。
将粉末状样品浸入4-MET/甲基丙烯酸甲酯（MMA）溶液中15分钟、3小时和24小时，制备粉末状样品。然后将它们干燥以进行光谱分析。使用配备低温冷却相机的实验拉曼微探针获取样品的光谱。
湿润24小时的样品光谱强烈表明，粉末状样品表面的Ca2+离子与4-MET之间存在强离子相互作用。然而，15分钟样品的光谱仅表明存在一定程度的氢键。3小时的4-MET/牙釉质粉样品的光谱显示出介于两者之间的特征。
本文给出的结果表明，4-MET与牙科底物之间的盐形成不太可能是瞬时的。相反，相对于共聚单体的聚合速率，这种反应的速率可能太慢，在临床条件下不太重要。因此，4-MET在4-MET/MMA树脂体系中的作用似乎是通过氢键润湿牙齿表面，然后使MMA单体扩散并更深地渗透过表面。该体系的主要键合机制更可能是由于微机械锁定机制。
