新型纳米磷酸钙正畸粘接剂钙磷离子充电的研究

The recharge methods of the novel calcium phosphate nanoparticle-containing orthodontic cement

目的:合成一种可以反复进行钙磷离子充电、释放以防止釉质脱矿的正畸粘接剂,并探究钙磷离子充电持续时间和频率对于离子再释放效能的影响。方法:可反复进行钙磷离子充电的粘接剂由均苯四甲酸二甲基丙烯酸甘油酯(PMGDM)和乙氧基化双酚A二甲基丙烯酸酯(EBPADMA)组成。纳米磷酸钙(NACP)以40%的质量分数混入树脂中。离体牙粘接托槽,使用万能试验机测试釉质粘接剂的抗剪切强度;在p H为4的酸性溶液中浸泡粘接剂样本,测量钙、磷离子的初期释放;再使用p H为7的充电液对释放完离子的样本进行充电,返回到p H为4的环境中测试再释放能力。结果:这种新型正畸粘接剂的抗剪切强度与商业化的正畸粘接剂无统计学差异(P>0.1)。样本在一次充电处理后,可以连续14 d持续释放钙、磷离子,而无需再次充电。离子再释放能力不会随着再充电/再释放循环次数的增加而降低(P>0.1)。14 d时离子的再释放浓度与不同的充电方式之间的关系为:1 min 3次>3 min 2次>1 min 2次>6 min 1次>3 min 1次>1 min 1次。结论:这种含NACP的可充电正畸粘接剂可以长期释放钙磷离子,抑制正畸托槽周围牙釉质脱矿。

Objective： The objectives of this study were to develop the first NACP rechargeable orthodontic cement, and investigate the effects of recharge duration and frequency on ion re-release efficacy. Methods： The rechargeable cement consisted of pyromellitic glycerol dimethacrylate （PMGDM） and ethoxylated bisphenol-A dimethacrylate （EBPADMA）. NACP were mixed into the resin at 40% by mass. Specimens were tested for orthodontic bracket shear bond strength （SBS） to enamel, Ca and P ion initial release was tested in pH 4 solution. After the ions were exhausted, the specimens were recharged in pH 7 solution and re-release in pH 4 solution again. The re-release of the ions were recorded. Results： The new orthodontic cement had SBS similar to commercial orthodontic cement without CaP release （p 〉 0.1）. Specimens after one recharge treatment （e.g., 1 minute immersion in recharge solution repeating 3 times in one day, referred to as 1 min 3 times） had substantial release of Ca and P ions continuously for 14 d without further recharge. The ion re-release did not decrease with increasing the number of recharge/re-release cycles （p 〉 0.1）. The ion re-release concentrations at 14 d versus various recharge treatments were： 1 min 3 times 〉 3 min 2 times 〉 1 min 2 times 〉 6 min 1 time 〉 3 min 1 time 〉 1 min 1 time. Conclusions： The present study developed the first orthodontic cement with Ca and P ion recharge and long-term release capability. This NACP rechargeable orthodontic cement is promising to inhibit enamel demineralization and WSL around orthodontic brackets.