改良正畸托槽填充物-缓释氟化钠微胶囊释氟性能的实验研究

目的研究改良正畸托槽新型填充物-缓释氟化钠微胶囊与正畸常用粘接剂GC混合后,氟释放情况。方法将氟化钠微胶囊按不同质量比例(10%,15%,20%,25%,30%,35%)与GC混合,填充在改良正畸托槽内,测定其在去离子水中氟的释放量随时间的变化情况。结果混有15%氟化钠微胶囊组在1～50天内的释氟浓度绝大多数测量点均高于其他组(P0.05),且释氟浓度相对稳定。结论 15%的氟化钠微胶囊与粘接剂混合释氟浓度相对较高且稳定。     

Fluoride release from NaF microcapsule used as modified orthodontic bracket addition

目的 研究改良正畸托槽新型填充物-缓释氟化钠微胶囊与正畸常用粘接剂GC混合后,氟释放情况.方法 将氟化钠微胶囊按不同质量比例(10%,15%,20%,25%,30%,35%)与GC混合,填充在改良正畸托槽内,测定其在去离子水中氟的释放量随时间的变化情况.结果 混有15%氟化钠微胶囊组在1~50天内的释氟浓度绝大多数测量点均高于其他组(P<0.05),且释氟浓度相对稳定.结论 15%的氟化钠微胶囊与粘接剂混合释氟浓度相对较高且稳定.     

含氟正畸托槽防脱矿性能的体外研究

目的 在体外条件下研究含氟正畸托槽防脱矿的能力,寻找能够有效预防固定矫治过程中釉质脱矿的方法.方法 将非改良托槽+0.2%氟化钠漱口水处理组、改良托槽组及对照组的托槽置于脱矿液(pH值5.0)和人工唾液(pH值7.0)中进行体外pH循环,每天2次,共35天.ISOMET 4000硬组织切片机制作牙齿磨片,IDA-2000高清晰度数码分析系统采集图像、观察并测量开窗区釉质脱矿深度及灰度.结果 在实验期间0.2%氟化钠组和含氟托槽组没有发生脱矿,而对照组产生约20μm 脱矿.灰度比较结果显示:0.2%氟化钠组和含氟托槽组没有显著差别,但两组均明显高于对照组.结论 改良金属正畸托槽在体外pH循环35天内能有效防止正畸托槽周围釉质脱矿发生,其防脱矿作用与0.2%氟化钠漱口水近似.     

粘贴含氟正畸托槽后菌斑和唾液中氟离子的变化

目的 测定粘贴含氟正畸托槽后,口腔内菌斑及唾液氟离子浓度的变化,探讨采用含氟正畸托槽预防牙釉质脱矿的意义.方法 选择10名志愿者,口腔内粘贴含氟正畸托槽.用离子选择性氟电极测定口腔内菌斑及唾液氟离子浓度,并与粘贴托槽前的基线水平相比较.结果 粘贴含氟正畸托槽后,菌斑及唾液中氟浓度均升高,唾液氟浓度持续3天高于基线水平,...     

含氟正畸陶瓷托槽长期氟释放性能的研究

目的 研发具有氟释放性能的正畸陶瓷托槽,体外条件下验证其长期氟释放的能力.方法 左上颌中切牙陶瓷托槽15个(3M公司美国):在托槽底板的牙侧用牙科高速手机制备一空腔.使用两种材料(磷酸锌水门汀+NaF、磷酸锌水门汀+CaF:)充填于腔内,然后在托槽底板上涂一层粘结剂(Fuji ORTHO LC或TransbondTM XT).利用离子液相色谱检测样本在去离子水中24 h释放出的氟离子浓度.实验第1周每天测试,此后的2个月每周测试一次(于测试前24 h更换去离子水),以后改为每月测试1次,持续9个月共315天.结果 虽然陶瓷托槽底板涂布了粘结剂,无论粘结剂本身是否含氟都没有阻止改良托槽的氟释放,而且起到了缓释的作用.结论 改良陶瓷托槽中以NaF为充填材料以RMGIC为粘接剂组的氟释放量最多;粘结剂的涂布没有阻止所填材料的氟释放,且起到了缓释作用.     

两种正畸粘接剂的临床应用效果分析

目的：比较树脂类正畸粘接剂（3M）和树脂改良型玻璃离子粘接剂（GC）粘接托槽的脱落率及牙釉质的脱矿率。方法：选取正畸治疗病例60例,采用自身对照方法在口内相对象限随机使用3M粘接剂和GC粘接剂粘接托槽,记录托槽的第一次脱落情况及治疗结束时牙釉质的脱矿情况。结果：3M粘接剂组托槽的脱落率为9.67%,GC粘接剂组托槽的脱落率为11.83%,两组之间无显著性差异（P〉0.05）;治疗结束时,3M粘接剂组牙釉质的脱矿率为21.5%,GC粘接剂组牙釉质的脱矿率为18.0%,两组之间存在统计学差异（P〈0.05）。结论：树脂改良型玻璃离子粘接剂与传统的树脂粘接剂都能够满足临床治疗需要,但是树脂改良型玻璃离子粘接剂可以免除酸蚀,且能释放氟离子,降低釉质脱矿的发生率。     

氟保护漆与含氟自酸蚀粘结剂预防固定正畸治疗早期釉质脱矿的临床研究

目的：对氟保护漆与含氟自酸蚀粘结剂预防固定正畸治疗早期釉质脱矿的临床效果进行对比研究,寻找一种更为有效的氟化物应用方法。方法：随机选择接受固定正畸治疗的青少年患者22名,在每个患者的1区和3区使用含氟自酸蚀粘结剂粘固托槽,在2区与4区常规酸蚀后使用化学固化型京津釉质粘结剂粘固托槽,随后涂布氟保护漆。采用DIAGNOdent激光荧光诊断仪分别对不同区域的牙面釉质脱矿程度进行定量诊断,并在患者1个月、3个月复诊时重复监测。结果：粘结完成即刻与粘结后1个月时,含氟自酸蚀粘结剂使用区（1区、3区）与涂氟保护漆区（2区、4区）之间DIAGNOdent读数均有显著性差异（P〈0.05）,前者读数低于后者。粘结后3个月时,两组间的DIAGNOdent读数无显著性差异。结论：含氟自酸蚀粘结剂降低了正畸托槽粘结时釉质的脱矿程度,在一定程度上有利于减轻正畸治疗早期釉质脱矿的进一步发生、发展。氟保护漆在促进脱矿釉质再矿化方面的作用优于含氟自酸蚀粘结剂。     

两种局部用氟方法预防口腔固定正畸矫治中釉质脱矿的临床研究

目的：研究含氟自酸蚀黏结系统和牙面酸蚀后涂氟保护剂这两种局部用氟方法对固定正畸釉质脱矿的预防作用。方法：选取109例采用固定正畸治疗的病人，随机分为3组，其中42例应用自酸蚀黏结系统黏结托槽，42例黏结托槽前涂布氟保护剂，21例黏结托槽时牙面不做任何特殊处理。在矫治开始前及12个月时观察记录所有牙唇颊面釉质脱矿指数以及在整个治疗过程中的托槽脱落率。结果：矫治前3组患牙组间釉质脱矿指数无显著性差异（P〉0．05）；矫治后两种局部用氟方法组釉质脱矿指数均低于对照组（P〈0．05），而两种局部用氟方法组间釉质脱矿指数无显著性差异（P〉0．05）；3组间的托槽脱落率亦无显著性差异（P〉0．05）。结论：两种局部用氟方法均对固定正畸矫治中釉质脱矿具有较好的预防作用，其黏结强度能够满足临床的需要，适宜口腔固定正畸临床使用。     

新型含氟正畸托槽对变形链球菌抑制性的实验研究

目的研究新型含氟正畸托槽对主要致龋菌变形链球菌生长繁殖的抑制性,探讨新型含氟正畸托槽对正畸固定矫治中牙釉质脱矿的预防作用。方法将新型含氟正畸托槽浸泡在去离子水中,每24h换液1次,留取2-5d的浸泡液,然后将浸泡液与变形链球菌菌悬液同时加入变形链球菌液体培养基中,厌氧培养后,观察菌悬液的光密度OD值变化。再将测过OD值的菌悬液经过固体培养基培养观察菌落数（CFU）。结果2、3、4d所得的含氟正畸托槽24h浸泡液经细菌培养后OD值与对照组相比,OD值减小且差异非常显著,5dOD值与对照组相比也减小,但差异无统计学意义。而菌落数的变化只是2、3d的与对照组相比,数目减少并且差异有统计学意义,4、5d的与对照组相比,数目也减少但差异无统计学意义。结论新型含氟正畸托槽在一定时间内对变形链球菌有抑制作用,其在正畸临床治疗中预防牙釉质脱矿的作用尚待进一步研究。     

四种正畸粘接剂对金属托槽粘接效果的评价

目的比较4种正畸粘接剂对金属托槽的粘接效果。方法选择正畸临床44例患者,792颗牙,随机分为4组,常规牙面处理,分别按照说明书要求用京津釉质粘接剂、GC树脂改良型玻璃离子粘接剂、3M化学固化型树脂粘接剂和3M光固化树脂粘接剂粘接金属托槽,然后使用MBT矫治技术进行综合性正畸治疗,记录托槽脱落情况。12个月后,评估每组牙的牙釉质脱矿情况,并对所有数据进行统计学分析。结果 3M光固化型树脂粘接剂组托槽的脱落率低于京津釉质粘接剂组,差异有显著性(P<0.05),而其余各组间托槽脱落率的比较差异均无统计学意义(P>0.05)。京津釉质粘接剂组造成釉质脱矿程度在4组中最高,而GC树脂改良型玻璃离子粘接剂的釉质脱矿程度最低,其差异均有统计学意义(P<0.05)。结论京津釉质粘接剂相对远期粘接效果较差;GC树脂改良型玻璃离子粘接剂能够通过释放氟离子有效降低釉质脱矿的发生,是正畸治疗中较为理想的粘接材料,具有良好的临床应用前景。     

选择性激光熔化技术在口腔医学中的应用

选择性激光熔化（Selective laser melting,SLM）技术是一种快速成型技术,它以其制作方便、快捷、产品组织结构密度高、精度高、避免传统加工方式原材料浪费等优点,被逐渐运用于各个行业。然而,在口腔医学中的应用还报道较少,主要集中在冠桥修复、可摘局部义齿支架、骨替代物及生物植片等方面。本文介绍了SLM技术的原理,分类以及在口腔医学中的应用特点和前景。     

A method for producing controlled fluoride release from an orthodontic bracket

The aim of this study was to manufacture and test, in vitro, a novel modification to provide fluoride-releasing orthodontic brackets. Thirty-two orthodontic brackets were drilled to produce a recess (approximately 1.3 mm in diameter and 0.7 mm in depth) at the centre of the bracket base. Four materials, with and without the addition of sodium fluoride, a glass ionomer cement (Ketac Cem micro), a resin-modified glass ionomer cement (RMGIC; GC Fuji Ortho LC), a zinc phosphate (Zinc Cement Improved), and a resin (Transbond XT) were used to fill the recess in the bracket base. Fluoride release was measured daily during the first week and then weekly for 10 weeks. An ion chromatograph with suppressed conductivity was used for free fluoride ion determination. Statistical analysis to determine the amount of flouride release was undertaken using analysis of variance and Tukey's test. During the first 2 weeks, the resin group, with the addition of 38 per cent sodium fluoride added, released significantly more free fluoride (P < 0.05), but after 2 weeks the fluoride release markedly decreased. After 5 weeks, the RMGIC group, with 15 per cent added sodium fluoride, had significantly higher (P < 0.05) daily fluoride release than the other groups. The findings demonstrated that an appropriate fluoridated material can be used as a fluoride-releasing reservoir in a modified orthodontic bracket to enable it to release fluoride over the period of fixed appliance treatment.     

A comparison of fluoride release by resin-modified GIC and polyacid-modified composite resin.

The objective of this study was to compare the fluoride release of 2 fluoride-containing orthodontic adhesives from bracketed teeth and adhesive disks, a resin-modified glass ionomer cement (Fuji Ortho LC, encapsulated; GC America Corp, Aslip, Ill) and a polyacid-modified composite resin (Assure; Reliance Orthodontic Products, Itasca, Ill). A composite resin without fluoride (Transbond XT; 3M Unitek, Monrovia, Calif) was used as a reference control. Metal brackets were bonded to the buccal surfaces of 120 human premolars (40 teeth per adhesive), and disks were made from each adhesive. The deionized storage water was changed, and fluoride release was measured at specified intervals up to 28 days for the bracketed teeth and up to 150 days for the disks. Fuji Ortho LC released 75% more accumulated fluoride than Assure (6.61 microg/bracket vs 3.77 microg/bracket) from bracketed teeth over the 28-day observation period. Assure released more fluoride per day than did Fuji Ortho LC from the disks during the first 3 months. For the rest of the 150-day period, Fuji Ortho LC released more fluoride per day than did Assure. The amount of fluoride released by these materials varied dramatically with different water-changing protocols. The large discrepancy between fluoride released from disks compared with that released from bracketed teeth suggests that caution must be used in extrapolating fluoride-release levels of adhesive disks to in vivo treatment conditions.     

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.     

Development of a sustained fluoride delivery system

Objective:To develop a novel delivery system by which fluoride incorporated into elastomeric rings, such as those used to ligate orthodontic wires, will be released in a controlled and constant manner.Materials and Methods:Polyethylene co-vinyl acetate (PEVA) was used as the model elastomer. Samples (N  =  3) were prepared by incorporating 0.02 to 0.4 g of sodium fluoride (NaF) into previously prepared PEVA solution. Another group of samples prepared in the same manner were additionally dip-coated in PEVA to create an overcoat. Fluoride release studies were conducted in vitro using an ion selective electrode over a period of 45 days. The amount of fluoride released was compared to the optimal therapeutic dose of 0.7 µg F⁻/ring/d.Results:Only coated samples with the highest fluoride content (group D, 0.4 g of NaF) were able to release fluoride at therapeutic levels. When fluoride release from coated and uncoated samples with the same amount of NaF were compared, it was shown that the dip-coating technique resulted in a fluoride release in a controlled manner while eliminating the initial burst effect.Conclusions:This novel fluoride delivery matrix provided fluoride release at a therapeutically effective rate and profile.     

Comparison of fluoride release protocols for in-vitro testing of 3 orthodontic adhesives.

The objective of this study was to compare the fluoride release of 3 orthodontic adhesives using disks and bracketed teeth with different storage protocols. The adhesives used were a resin-modified glass ionomer (RMGI) (Fuji Ortho LC; GC America, Aslip, Ill), a polyacid-modified composite resin (PMCR)(Assure; Reliance Orthodontic Products, Itasca, Ill), and a composite control, Transbond XT (3M Unitek, Monrovia, Calif). Metal brackets were bonded to the buccal and lingual surfaces of 120 extracted human premolars. Five plastic containers holding 4 teeth (8 brackets) were used for each adhesive protocol. The samples were stored in containers holding 4 mL of deionized water at 37 degrees C for 28 and 84 days for the brackets and disks, respectively. The bracketed samples released larger initial amounts of fluoride compared with the disk samples during the first 5 to 6 days for both fluoride-releasing adhesives. The PMCR (Assure) released more fluoride (mg/cm(2)/day) than did the RMGI (Fuji Ortho LC) in all protocols with the exception of daily protocols when values diminished below the RMGI values near the 24th day and between the 56th and the 70th days for the bracketed and disk samples, respectively. Inconsistent values for fluoride release were noted in the bracket and disk samples when compared with daily versus cumulative water changes. Daily water changes revealed higher fluoride release levels (brackets), but this trend was not evident in the disk samples. Daily water changes may yield more clinically relevant data on fluoride release.     

新型正畸粘接剂氟释放特征的研究

目的研究一种新型正畸粘接剂的氟释放特征。方法将不同比例的甲基丙烯酸甲酯、甲基丙烯酸羟乙酯、氟化钠和聚甲基丙烯酸甲酯相混合,构成3个实验组,对照组为玻璃离子水门汀。测量样本24h的氟释放量。在最初7d每天测量一次,此后的一个月每周测量一次,之后为每月测量一次,持续测量4个月,并定期记录样本重量的改变。采用单因素方差分析对数据进行统计分析。结果含有10%氟化钠、90%聚甲基丙烯酸甲酯的粉,含有40%甲基丙烯酸羟乙酯和60%甲基丙烯酸甲酯液组成的粘接剂在112天中具有与玻璃离子水门汀相似的氟释放量。甲基丙烯酸羟乙酯含量为40%的粘接剂的重量增加值明显高于其他组。结论含有10%氟化钠、90%聚甲基丙烯酸甲酯的粉,含有40%甲基丙烯酸羟乙酯和60%甲基丙烯酸甲酯液组成的粘接剂具有令人满意的氟释放特征。     

Cariostatic effect and fluoride release from a visible light-curing adhesive for bonding of orthodontic brackets.

This study was designed to investigate the cariostatic potential in vivo of a visible light-curing adhesive for the bonding of orthodontic brackets. The fluoride release of the adhesive in water and saliva was also measured. Ten orthodontic patients with premolars to be extracted participated. One bracket with Heliosit-Orthodontic (no fluoride) was positioned on the buccal surface of one premolar (control), and another bracket with Orthodontic cement VP 862 (containing fluoride) was positioned on the experimental contralateral premolar. The adhesives were cured with a Heliolux II lamp, and the teeth were extracted after 4 weeks. The patients used a fluoride toothpaste during the experiment. The mineral content of the enamel adjacent to the brackets was determined by quantitative microradiography. The fluoride release from disk-shaped plates of the fluoride adhesive was measured in water for a 6-month period and in human saliva for 24 hours. The fluoride adhesive reduced lesion depths by about 48% than the nonfluoride adhesive (P less than 0.05, t test). The largest release of fluoride from the plates in water was observable within the first week. However, a significant amount of fluoride was still released after 6 months. The fluoride release in saliva was significantly lower in human saliva at pH 7 than in water (P less than 0.01, t test). When salivary pH was lowered to 4, to mimic a cariogenic challenge, the amount of fluoride released increased up to the value measured in water. It was concluded that the regular use of fluoride toothpastes is insufficient to inhibit lesion development around orthodontic brackets.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of brushing on fluoride release from 3 bracket adhesives.

The purpose of this in vitro study was to compare fluoride ion release from 3 orthodontic bracket adhesives with and without brushing the bracketed teeth with a fluoridated dentifrice. The bracket adhesives included a light-cured composite resin (Transbond; 3M Unitek, Monrovia, Calif), a fluoride-releasing composite resin (Advance; L D Caulk Division, Dentsply International, Milford, Del), and a resin-modified glass ionomer (Fuji Ortho LC; GC America, Alsip, Ill). The teeth in the control group were not bonded with brackets. Sixty extracted human teeth were randomly assigned to 6 groups of 10 each: (1) Transbond, brushed; (2) Advance, brushed; (3) Advance, not brushed; (4) Fuji, brushed; (5) Fuji, not brushed; and (6) control, brushed. After bonding, each tooth was placed in a sealed plastic test tube containing 4 ml of deionized water. The toothpaste used in brushing contained 0.15% weight per volume sodium fluoride, 1500 parts per million parts fluoride (Winter-fresh gel; Colgate-Palmolive Co., New York, NY). Brushing began 24 hours after the teeth were bonded and placed in deionized water. After brushing, the teeth were thoroughly rinsed with deionized water and returned to a sealed test tube. Fluoride measurements were taken before brushing began, at intervals of 72 hours for 22 days, and 90 and 93 days after bonding. Findings included: (1) brushing significantly increased the release of fluoride ions from the teeth in the composite resin and control groups, (2) the enamel crowns of the unbonded control teeth absorbed and re-released a substantial amount of fluoride ions obtained from the toothpaste, (3) the brushed group of teeth bonded with the fluoride-releasing composite resin released significantly more fluoride on the last 4 days that measurements were taken after brushing than the nonbrushed group bonded with the same adhesive, (4) the brushed group of teeth bonded with the resin-modified glass ionomer released significantly more fluoride on the last 4 days that measurements were taken after brushing than the nonbrushed group bonded with the same adhesive, and (5) all groups released small amounts of fluoride ions 90 and 93 days after bonding (68.5 and 71.5 days after brushing ended); the resin-modified glass ionomer groups released significantly more fluoride than the other groups. Brushing with fluoridated toothpaste produced significantly greater fluoride release from teeth bonded with all 3 adhesives, and from the unbonded control teeth.