The University of Sydney, Westmead Oral Health Centre, Sydney, Australia.
Oper Dent. 2011 Jul-Aug;36(4):422-32. doi: 10.2341/10-414-L. Epub 2011 Aug 5.
To determine the fluoride release and recharge of three fluoride-containing resin composites when aged in deionized water (pH 6.5) and lactic acid (pH 4.0) and to assess mechanical properties of these composites following aging.
Three fluoride-containing resin composites were analyzed in this study; a new giomer material named Beautifil II, Gradia Direct X, and Tetric EvoCeram. A glass ionomer cement, Fuji IX Extra, was also analyzed for comparison. Specimens were fabricated for two test groups: group 1 included 10 disc specimens initially aged 43 days in deionized water (five specimens) and lactic acid (five specimens). The fluoride release from these specimens was measured using a fluoride-specific electrode on nine specific test days during the aging period. Following 49 days of aging, each specimen was recharged in 5000 ppm neutral sodium fluoride solution for 5 minutes. Specimen recharge was then repeated on a weekly basis for 3 weeks. The subsequent fluoride rerelease was measured at 1, 3, and 7 days after each recharge episode. Group 2 included six disc specimens aged for 3 months in deionized water (three specimens) and lactic acid (three specimens). The hardness and elastic modulus of each specimen was measured using nano-indentation at intervals of 24 hours, 1 month, and 3 months after fabrication. Two-way factorial analysis of variance (ANOVA) and post-hoc (Tukey) testing was used to assess the influence of storage media (two levels) and composite type (three levels) on the fluoride release, fluoride rerelease, hardness, and elastic modulus of the assessed materials. The level of significance was set at p=0.05.
All three composites demonstrated fluoride release and recharge when aged in both deionized water and lactic acid. The cumulative fluoride released from Beautifil II into both media was substantially greater than the fluoride released from Gradia Direct X and Tetric EvoCeram after 43 days aging and was significantly (p<0.05, ANOVA, Tukey test) greater during several analysis periods. Beautifil II demonstrated the greatest recharge ability of the three composites over the 3-week recharge period in both media. Fuji IX Extra demonstrated a significantly (p<0.05) greater fluoride release and recharge compared with the three resin composites. The elastic modulus and hardness of the three composites did not decrease significantly (p<0.05) with fluoride release or fluid uptake over the 3-month aging period, in either media.
The three composites in the present study demonstrated fluoride release (Beautiful II > Gradia Direct X > Tetric EvoCeram) and fluoride recharge (Beautiful II > Gradia Direct X > Tetric EvoCeram). This capability raises the possibility of fluoride-containing composites exhibiting a lower incidence of recurrent caries than non fluoride–containing composites. The mechanical properties of each composite did not diminish with aging and fluoride release over the testing period.
研究三种含氟树脂复合材料在去离子水（pH6.5）和乳酸（pH4.0）中的氟释放和再补充情况，并评估这些复合材料在老化后的力学性能。
本研究分析了三种含氟树脂复合材料；一种新型玻璃离聚物材料名为 Beautifil II、Gradia Direct X 和 Tetric EvoCeram。还分析了一种玻璃离子水门汀 Fuji IX Extra 进行比较。制备了两组试件：第 1 组包括 10 个圆盘试件，最初在去离子水中老化 43 天（5 个试件）和乳酸（5 个试件）。在老化期间的 9 个特定测试日使用氟离子特异性电极测量这些试件的氟释放量。经过 49 天的老化，每个试件在 5000ppm 中性氟化钠溶液中再充电 5 分钟。然后每周重复一次充电，持续 3 周。在每次充电后 1、3 和 7 天测量随后的氟再释放量。第 2 组包括在去离子水中老化 3 个月的 6 个圆盘试件（3 个试件）和乳酸（3 个试件）。在制备后每隔 24 小时、1 个月和 3 个月使用纳米压痕法测量每个试件的硬度和弹性模量。采用双因素方差分析（ANOVA）和事后（Tukey）检验评估储存介质（两个水平）和复合材料类型（三个水平）对评估材料的氟释放、氟再释放、硬度和弹性模量的影响。显著性水平设为 p=0.05。
三种复合材料在去离子水和乳酸中老化时均表现出氟释放和再补充能力。Beautifil II 在两种介质中释放的累积氟量明显大于 Gradia Direct X 和 Tetric EvoCeram 老化 43 天后释放的氟量，并且在多个分析期内显著（p<0.05，ANOVA，Tukey 检验）更高。Beautifil II 在两种介质的 3 周再充电期间表现出最强的三种复合材料的再充电能力。Fuji IX Extra 与三种树脂复合材料相比，显示出明显（p<0.05）更高的氟释放和再补充能力。在 3 个月的老化过程中，三种复合材料的弹性模量和硬度均未因氟释放或流体吸收而显著（p<0.05）降低，无论是在何种介质中。
本研究中的三种复合材料表现出氟释放（Beautifil II > Gradia Direct X > Tetric EvoCeram）和氟再补充（Beautifil II > Gradia Direct X > Tetric EvoCeram）能力。这种能力增加了含氟复合材料比不含氟复合材料发生复发性龋齿的可能性更低。在测试期间，每种复合材料的机械性能都没有随着老化和氟释放而降低。
