多功能正畸粘接剂预防釉质脱矿的体外研究

In vitro study of multifunctional orthodontic cement for prevention of enamel demineralization

目的本研究将抗蛋白制剂(MPC)、抗菌性季铵盐单体(DMAHDM)、再矿化纳米颗粒(NACP)添加到正畸粘接剂中,形成多功能正畸粘接剂(MOC),评价此粘接剂预防托槽周围釉质脱矿的性能。方法采用Transbond XT、RMGI、RMGI+MPC+DMAHDM、MOC四组材料在离体牙上粘接托槽。应用菌斑生物膜模型对离体牙脱矿14天后,检测釉质脱矿深度,横断面显微硬度,釉质脱矿形貌和矿质元素含量。结果MOC组在距托槽50~150μm、150~250μm、250~350μm的部位脱矿深度分别为(42.81±17.05)μm,(47.72±18.99)μm和(58.18±21.34)μm,明显小于其他三组材料(P<0.05)。MOC组脱矿后距托槽100~300μm处的硬度梯度最高。MOC组釉质表面脱矿程度最轻,Ca/P为1.79±0.11,高于其他三组材料(P<0.05)。结论多功能正畸粘接剂减少了托槽周围釉质脱矿,对于预防正畸釉质白斑发生具有临床应用价值。

Objective To evaluate the effect of multifunctional orthodontic cement(MOC)on prevention of enamel demineralization.Methods The MPC,DMAHDM,and remineralizing nanoparticles of amorphous calcium phosphate(NACP),were incorporated into the commercial RMGI cement,to develop MOC.Bracket-enamel samples were prepared and bonded in four groups,Transbond XT,RMGI(resin-modified glass ionomer),RMGI+MPC(2-methacryloyloxyethyl phosphorylcholine)+DMAHDM(dimethylaminohexadecyl methacrylate)and MOC[MPC+DMAHDM+NACP(nanoparticles of amorphous calcium phosphate)].Enamel near the bracket was demineralized by dental biofilm inoculum for 14 days.Lesion depths around brackets were tested by polarized-light microscopy.Cross-sectional enamel hardness was evaluated by microhardness indenter.Morphology and element contents were studied by scanning electron microscopy and X-ray energy disperse spectroscopy.Results The depths of demineralization at 50-150,150-250 and 250-350μm from brackets in MOC group were(42.81±17.05),(47.72±18.99)and(58.18±21.34)μm,respectively,which were significantly lower than those of the other three groups(P<0.05).The hardness gradient of MOC group was the highest at 100-300μm from the bracket after demineralization.The degree of demineralization of enamel surface in MOC group was the lightest,Ca/P was 1.79+0.11,which was higher than that of other three groups(P<0.05).There was little demineralization seen on the enamel surface of MOC near brackets,the Ca/P of MOC after demineralization was 1.79±0.11,significantly higher than other groups.Conclusion Multifunctional orthodontic adhesives can reduce enamel demineralization around brackets and have clinical application value in preventing enamel leukoplakia.