飞行时间质谱仪监测不同聚合温度下义齿基托树脂中甲基丙烯酸甲酯释放量的研究

Methyl methacrylate released from autopolymerized denture base polymers at different polymerization temperature during processing-monitoring by time-of-flight mass spectrometer

关键词:  甲基丙烯酸甲酯类  义齿基托  飞行时间质谱仪

Key words:  methyl methacrylates  denture base polymers  time-of-flight mass spectrometer

摘要:

目的　探讨使用飞行时间质谱仪监测不同聚合温度下自凝树脂反应时释放的甲基丙烯酸甲酯（methyl methacrylate，MMA）的量，分析MMA释放量的变化趋势，研究聚合温度对MMA释放量的影响。　方法　按生产厂家要求的比例把自凝仿生义齿基托树脂粉2 g和液1 g调拌40 s后，立即用飞行时间质谱仪连续监测MMA释放量，待释放量的变化稳定后停止监测。室温20℃和40℃、60℃水浴下各监测5个样本，每分钟记录1次监测结果，并加以比较。　结果　不同聚合温度下自凝树脂反应时释放的MMA的量的变化趋势相像：在反应初期20℃、40℃和60℃时MMA释放量低，变化不明显， 而分别在11 min、（46.2±3.5）mg/L；6 min、（6.4±0.5）mg/L；2 min、（7.2±1.2）mg/L时开始快速升高，之后分别在13 min、（225.4±23.1）mg/L；7 min、（57.7±5.4）mg/L；4 min、（38.1±4.9）mg/L时到达最高，然后由快速下降到缓慢下降并分别在23 min、（9.4±1.6）mg/L；12 min、（1.3±0.1）mg/L；6 min、（1.3±0.2）mg/L时趋于稳定。40℃与20℃、60℃与20℃相比MMA释放量小，并且到达稳定期的时间短（P<0.05），40℃与60℃相比MMA的释放量无明显差异（P>0.05）。　结论　把聚合温度从室温20℃升高到40℃或60℃时可以降低自凝树脂反应过程中释放的MMA的量，但从40℃继续升高到60℃时MMA的释放量无显著变化。

Abstract:

Objective　Time-of-flight mass spectrometer was investigated for monitoring methyl methacrylate (MMA) released from autopolymerized denture base polymer (self-curing resin) at different polymerization temperature during processing. The effect of the polymerization temperature on the amount of MMA was analyzed.　Methods　Self-curing resin was mixed in the container at room temperature (20℃) using a ratio of 2 g of powder to 1 g of liquid in accordance with the manufacturer’s instructions for 40s as a specimen. The amount of MMA released from the specimen was on line analyzed and simultaneously recorded every minute by time-of-flight mass spectrometer since immediately after mixing. A total of 15 specimens were monitored and analyzed for each curing cycle (five at room temperature 、five in water-bath at 40℃ and five in water-bath at 60℃).　Results　The tendencies of MMA released from 3 groups of specimens were similar. The releasing amounts of MMA in a water-bath at 40℃ and in a water-bath 60℃ were lower than the one at room temperature (P<0.05). There was no significant difference in the releasing amounts of MMA between in a water-bath at 40℃ and in a water-bath 60℃ (P>0.05). The highest level were reached at 13 min（225.4±23.1）mg/L at room temperature，7 min（57.7±5.4）mg/L in a water-bath at 40℃，4 min（38.1±4.9）mg/L in a water-bath at 60℃.　Conclusions　Increasing polymerization temperature for self-curing resin from 20℃ to 40℃ or 60℃significantly reduced the releasing amount of MMA during processing. But Increasing polymerization temperature from 40℃ to 60℃ didn’t significantly reduced the one.