含氟树脂氟释放率的体外试验

目的 通过观察几种不同浓度含氟树脂氟的释放率，试图寻找一种较为理想的给氟剂量，以达到预防义齿基牙龋的目的。方法 将含ＣａＦ２５％、１０％、１５％、２０％、２５％的树脂块分别放入１００ｍｌ、２００ｍｌ、５００ｍｌ蒸馏水中浸泡。用电位法测量水中氟离子浓度，观察树脂氟的释放速率及释放规律。结果 ２０％的含氟树脂其氟释放速率优于其它浓度的含氟树脂。结论 ＣａＦ２微溶于水，混入固化的树脂中，具有良好缓释氟的     

不同含氟试剂的热凝树脂释氟率的比较研究

目的比较不同含氟试剂的热凝树脂释氟率,为寻找适宜的预防义齿基牙龋的氟试剂和氟含量提供理论依据。方法将NaF、Na2PO3F、CaF23种试剂分别制成含氟5%、10%、15%、20%的热凝树脂块(聚甲基丙烯酸甲酯),于100ml去离子水中浸泡。选择电极法测定各浸泡液中氟释放量。结果同浓度下各含氟试剂块氟释放量为NaF>Na2PO3F>CaF2,且含氟浓度越高氟释放量也越大。结论各含氟树脂块均能释放氟离子。     

含氟热凝树脂预防可摘局部义齿基牙龋的体外研究

目的:研究基托局部含氟对基牙的防龋作用.方法:将10颗健康离体牙制成20块2～3mm厚的釉质块,采用配对设计的实验方法,利用简易人工口腔装置,分别随机地紧邻于含氟及无氟热凝树脂块,流动人工唾液冲洗.每周测定人工唾液的氟浓度,四周后测定各釉质块的表面显微硬度及抗酸性.结果:两组中人工唾液氟浓度无显著性差异,表面显微硬度及酸蚀后的龋损深度有显著性差异.结论:含氟树脂有利于预防可摘局部义齿基牙龋.     

3种玻璃离子水门汀氟释放能力的体外研究

目的：对比研究3种玻璃离子水门汀在人工唾液中的氟释放能力。方法：选择FujiCem、FujiPlus和FujiI水门汀，分别制备10个直径4mm，高8mm的试样，每个试样浸入1ml人工唾液中，恒温37℃。采用离子选择电极分别于第1d、2d、3d、7d、14d、30d、90d测定3种材料的氟释放量。采用SPSS13．0软件进行统计分析。结果：3种材料均在第1d的氟释放量最高。第2d急剧下降，随后氟离子释放趋于平稳。在各个测量时间点，FujiCem的氟释放累积量最高，除了第1d外，FujiPlus释放量最低，且3种材料在90d测定的氟累积释放量总体均数间、组间两两比较均存在显著差异，P〈0．05，有统计学意义。结论：3种材料均能在一定时间内持续缓慢地向周围环境中释放氟离子，而FujiCem显示出更好的氟离子释放能力，在预防继发龋的发生方面具有一定的优势。     

树脂加氟预防可摘局部义齿基牙龋的初步研究

目的：探索树脂加氟预防可摘局部义齿基牙龋的可行性，方法：对自制加氟自凝树脂进行横向弯曲，体外和体内释放试验。结果：氟对自凝树脂横向弯曲变形无不利影响；加氘树脂在生理盐水中持续低浓度释放氟离子，置于局部义齿中后，相邻基牙菌班内氟离子浓度较对照牙有显著升高（P＜0．01），而唾液中氟离子浓度无明显变化（P＞0．01），结论 ：树脂加氟可在一定时间内持续有效提高局部氟离子浓度。     

氟化聚甲基丙烯酸甲酯体外释氟率的测定

目的:通过对含氟聚甲基丙烯酸甲酯体外释氟率的测定,为寻找较为理想的氟含量预防义齿基牙龋提供理论依据。方法:将分别含氟化钙、单氟磷酸钠10%、15%、20%、25%(重量比)5种不同浓度的热凝和自凝树脂各3块,分别于100ml、200ml去离子水中浸泡,定期取液,测量溶液中的氟离子浓度。结果:各浓度的含氟树脂块均能释放氟离子。结论:含单氟磷酸钠15%热凝树脂和10%的自凝树脂是比较好的含氟比例。含氟化钙20%热凝树脂和15%的自凝树脂是比较好的含氟比例。     

玻璃离子水门汀释放氟实验研究

目的　观察玻璃离子水门汀固化体 (GIC)在蒸馏水和人工唾液中释放氟状况。方法　选择 6种GIC ,每种材料制备成 8mm× 5mm的 5个溶出片 ,分别浸于 5ml的 37℃蒸馏水和人工唾液中 ,在 1、3、5、7、14、2 1、2 8、5 6d更换溶出液 ,并应用气相色谱和氟离子选择电极方法测定溶出液中氟含量。结果　GIC固化体释放氟量 2 4h内最高 ,然后急剧减低 ,14～ 5 6d间虽有减低但仍持续释放一定量氟 ;GIC(GCTypeIII、3M、上海青浦 )在蒸馏水中释放氟量明显高于人工唾液 ,松风产GIC在人工唾液中释放氟量明显高于蒸馏水中释放氟量 ;气相色谱测定溶出液氟量明显高于氟离子选择电极方法测定值。结论　本研究的 6种玻璃离子水门汀均能够释放氟 ,推测可能具有预防继发龋的作用     

美观充填材料氟离子释放的体外研究

目的：分析3种传统玻璃离子水门汀、4种玻璃离子树脂复合体和1种树 脂的释氟能力。方法：在体外测量每一个材料应用含氟凝胶前后各6周的氟离子释放量。结果：部分材料在测量初2d释氟水平高，之后迅速下降，在3－5周内维持于稳定水平。用含氟凝胶进行氟再吸收后。所有材料均有短暂而显著的释氟增加。结论：新型的复保体同玻璃离子水门汀一样，起氟储存库的作用。     

无基托可摘局部义齿的临床应用

作者选择了４１例牙列缺损患者，为其设计并制作成无基托的可摘局部义齿，对其中的２９例作了追踪观察，效果良好。本文就无基托的ＲＰＤＳ的适应证，设计原则及患者的修复效果等方面进行了讨论。     

玻璃离子粘固剂及复合体氟离子体外释放的比较

目的:比较不同类型玻璃离子粘固剂(GIC)及复合体在体外释放氟离子的能力。方法:选择树脂改良型GIC(VITREBOND;FUJIⅡLC),传统型GIC(FUJIⅡ;国产GIC;GLASLONOMER)及复合体(DYRACT)作为实验对象。使用氟离子选择电极,连续14d测定各种材料固化后标本浸泡溶液中的氟离子浓度,采用光固化树脂(Z100)作为实验对照组。实验数据采用单因素方差分析和q检验法检验。结果:5种GIC均显现出较高的初期氟离子释放,2 d后氟离子释放趋于平稳;复合体显现出一种平缓的氟离子释放状态。树脂改良型GIC的累计氟离子释放量明显高于其他材料,其由高到低的顺序为:VITREBOND>FUJIⅡLC>国产GIC>DYRACT>FUJIⅡ>GLASLONO-MER(P<0.05)。结论:树脂改良型GIC较传统型GIC和复合体具有更好的氟离子释放能力,在预防继发龋上可能具有一定的优势。     

氟化物涂膜体外释氟情况研究

作者研究氟化物涂膜在体外使用后氟化物的释放情况，发现涂膜对于其中的氟化物有一定的缓释作用，但这种缓释作用的速度并不均匀，以开始一分钟的释放速度最快，以后释放速度明显减２４小时涂膜释氟量约占其总含量３０％，由于这种缓释作用，可使局部环境中氟化物保持一定浓度，延长氟化物与釉质对接触时间，阻止羟磷灰玫瑰溶解，促进脱矿釉质的再矿化。     

Long-term in vitro fluoride release and rerelease from orthodontic bonding materials containing fluoride.

The purpose of this study was to compare in vitro long-term (30 month) fluoride release and rerelease rates (after fluoride exposure) from 3 orthodontic bonding materials containing fluoride and 1 without fluoride. Ten samples of each material (Python, TP Orthodontics, LaPorte, Ind; Assure, Reliance Orthodontic Products, Itasca, Ill; Fuji Ortho LC, GC America, Alsip, Ill; and Transbond XT, 3M Unitek, Monrovia, Calif) were fabricated and stored in deionized distilled water at 37 degrees C. Five samples had fluoride-release rates measured at days 546, 637, 730, 821, and 913 after initial fabrication, and 5 samples were exposed to fluoride (Nupro 2% NaF gel, Dentsply Canada, Woodbridge, Ontario, Canada) for 4 minutes at day 535 and had measurements taken on days 546, 548, 552, 575, 637, 730, 821, and 913. To prevent cumulative measurements, the storage solutions were changed 24 hours before measurement. Statistically significant differences were found in fluoride-release rates (P <.0001), with Fuji Ortho LC releasing the most fluoride, followed by Python and Assure at all time points in the nonfluoride exposed group. In the fluoride-exposed group, there were significant differences in fluoride release (P <.0001), with Fuji Ortho LC releasing the most fluoride. A "burst-effect" pattern of fluoride release was seen after fluoride exposure for all materials. It was concluded that Fuji Ortho LC, Assure, and Python might have sufficient long-term fluoride-release rates to reduce white spot formation, and all are recommended as suitable fluoride-releasing orthodontic bonding materials.     

Inhibition of tooth erosion by milk containing different fluoride concentrations: An in vitro study

Objectives

This in vitro study assessed the effect of milk containing different fluoride concentrations on tooth erosion.

Methods

Bovine enamel and root dentine specimens were treated with: (1) bovine whole milk with 0 ppm F; (2) 2.5 ppm F; (3) 5 ppm F; (4) 10 ppm F (all after erosion); (5) whole milk with 0 ppm F (before erosion); (6) NaF (0.05% F, positive control, after erosion) or (7) 0.9% NaCl (negative control, after erosion). The specimens were submitted to pH cycles (4× 90 s in soft drink) and treatments for 5 days. The specimens were immersed in the treatment solutions for 1 min (only at the first cycle each day) with further exposition to 1:1 milk:saliva slurry for 10 min. The tooth loss was measured using a contact profilometer and statistically analysed (p < 0.05).

Results

Rinsing with milk before erosive challenge significantly reduced tooth loss compared to negative control (67% and 24% reduction in dentine and enamel loss, respectively) and to milk after erosive challenge, only for dentine. The addition of fluoride to milk also reduced tooth loss compared to negative control, but with no significant differences among fluoride concentrations for enamel and dentine (μm), respectively: 0 ppm (3.63 ± 0.04 and 2.51 ± 0.53), 2.5 ppm F (2.86 ± 0.42 and 1.96 ± 0.47), 5 ppm F (2.81 ± 0.27 and 1.77 ± 0.44), 10 ppm F (2.03 ± 0.49 and 1.68 ± 0.59). There was a negative and significant correlation between [F] and the tooth loss.

Conclusions

Daily rinse with milk containing F is able to reduce both enamel and dentine erosion in vitro.

Clinical significance

Since the prevalence of dental erosion is steadily increasing, rinse with milk or its derivate might be an important strategy to reduce the progression of tooth erosion.     

An estimation of fluoride release from various dental restorative materials at different pH: In vitro study

Background: In the mid of 1980s, the cariostatic effect of fluoride ions on enamel caries had been demonstrated in many studies. The use of fluoride releasing dental restorative materials has seen increasing from many years for the specific purpose of leaching of fluoride into the surrounding tissues to inhibit secondary dental caries as well as prevention of caries in the newly erupted tooth. In the dental caries, acidic environment causes the demineralization of tooth structure and also affect the restorative margins of dental restoration. Aim: various restorative materials show different behavior in different pH conditions of oral cavity. Thus, the aim of this study was to evaluate the fluoride release of the various restorative materials at different pH. Design: In this in vitro study, 30 samples of each dental restorative material were prepared and grouped into five with six samples in each group as per the pH of the solution 4.3, 4.6, 5.0, 5.5, and 6.2. All the samples were subjected to alternate cycling of the demineralizing solution (6 h) and remineralizing solution (18 h) for 15 days. Results: the fluoride release was measured by using fluoride ion specific electrode and digital ion analyzer. The result showed that the fluoride release rate was significantly higher in first day and reduced after third day to nearly constant level. At pH 4.3, the fluoride release was highest and lowest at pH 6.2. Conclusion: the Amalgomer CR showed the highest fluoride release among all the experimental dental restorative materials.     

An in vivo study on the release of fluoride from glass-ionomer cement

Fluoride release from a glass-ionomer cement was measured in vivo during an 8-day period. Maxillary acrylic resin appliances, each carrying four glass-ionomer cement specimens, were worn by four subjects at night. Unstimulated whole saliva samples were collected before the subjects retired to bed (pretreatment samples) and in the morning (posttreatment samples). The average fluoride concentration and saliva flow of pretreatment samples were 31 +/- 4 ng/mL and 0.5 +/- 0.1 mL/min, respectively. In all subjects there was a statistically significant posttreatment increase (.005 less than P less than .025) in salivary fluoride concentration. The release of fluoride was nearly constant during the test period.