Evaluation of the fluoride release and ability to recharge in different glass ionomer cements

Objective To evaluated the ability to fluoride release and recharge in the different glass ionomer cements during simulation of cariogenic challenge. Material and method Twelve samples were made for each experimental group: conventional glass ionomer cements, Maxxion R (FGM), Ketac Molar EasyMix (3M ESPE); resin modified glass ionomer cement, Vitrebond (3M ESPE); and composite resin Filtek™ Z350XT (3M ESPE), negative control. The samples were immersed alternately in pH cycling method, remaining 6 hours in demineralization solution and 18 hours in remineralization solution and maintained at 37 °C. Fluoride release was measured 1, 2, 7, and 14 days before and after recharging with specific electrode coupled to the analyzer apparatus pH/fluoride, each measurement with calibrated solutions of sodium fluoride to 1 and 10 ppm, prepared with TISAB II. For reading was added 0.5 mL of sample to an equal volume of TISAB II. Recharging was made with neutral sodium fluoride to 2% for 4 minutes in the samples, washed and again immersed pH cycling solutions. Data were subjected to two-way ANOVA and Tukey’s post-hoc test (α = 0.05). Result The initial fluoride release (μgF/cm2) was 45.36 ; 37.49 and 26.35 for Maxxion R, Vitrebond and Ketac Molar EasyMix, respectively. Significant differences between the materials before and after recharging were observed (p=0.001). After topical application of fluoride, both showed ability to recharge. Conclusion The glass ionomer cements evaluated were capable of releasing fluoride in pH cycling solutions and may recharge through of a topical application.

研究目的 本研究旨在评估不同玻璃离子水门汀（glass ionomer cements）在模拟致龋挑战环境下的氟离子释放与氟再负载能力。
材料与方法 本研究为每个实验组制备12份试样：传统型玻璃离子水门汀包括Maxxion R（FGM品牌）、Ketac Molar EasyMix（3M ESPE品牌）；树脂改性型玻璃离子水门汀包括Vitrebond（3M ESPE品牌）；以及作为阴性对照的复合树脂Filtek™ Z350XT（3M ESPE品牌）。试样采用pH循环（pH cycling）法交替浸泡：在脱矿液中放置6小时，再置于再矿化液中放置18小时，全程维持37℃环境。分别在氟再负载前后的第1、2、7、14天测量氟离子释放量：使用与pH/氟离子分析仪配套的专用电极，以浓度为1ppm与10ppm的氟化钠校准液进行校准，校准液采用TISAB II试剂配制。检测时，取0.5mL试样与等体积的TISAB II试剂混合后进行读数。氟再负载操作：将试样置于2%中性氟化钠溶液中处理4分钟，随后冲洗干净，再次浸入pH循环溶液中。采用双因素方差分析（two-way ANOVA）与Tukey事后检验（Tukey’s post-hoc test）对数据进行统计分析，显著性水平设定为α=0.05。
研究结果 初始氟离子释放量（单位：μgF/cm²）分别为：Maxxion R 45.36、Vitrebond 37.49以及Ketac Molar EasyMix 26.35。各材料在氟再负载前后的氟释放量均存在显著差异（p=0.001）。经局部氟化物涂覆后，所有受试材料均表现出氟再负载能力。
结论 本研究评估的玻璃离子水门汀均可在pH循环溶液中释放氟离子，且可通过局部氟化物涂覆实现氟再负载。