生物活性玻璃对早期人工釉质龋的再矿化*

背景:生物活性玻璃具有良好的生物相容性,且具有抑制口腔致龋细菌和牙周相关细菌及抗牙本质过敏的作用.目的:评价生物活性玻璃促进早期人工釉质龋再矿化的作用.方法:将新鲜拔除的30颗牛切牙制成人工龋模型,将标本在37℃人工脱矿液内脱矿72 h,用扫描电镜观察脱矿后釉质表面的平滑情况,用显微硬度仪测量脱矿后釉质的显微硬度.然后随机分为3组,每组10个.采用pH循环法模拟人口腔环境,将3组标本分别浸泡在生物活性玻璃溶液、氟化钠溶液及人工唾液内,3次/d,10 min/次,循环浸泡20 d,扫描电镜检测标本脱矿及再矿化情况,用显微硬度计检查牙釉质显微硬度.结果与结论:浸泡在生物活性玻璃溶液中的牙釉质表面较浸泡在其他两溶液中的牙釉质表面光滑平整,无空隙存在;浸泡在生物活性玻璃溶液中的牙釉质表面显微硬度高于浸泡在其他两溶液中的牙釉质表面显微硬度(P <0.05).说明生物活性玻璃在体外实验中能促进早期釉质龋的再矿化.     

基于光学相干断层成像量化评估平滑面早期牙釉质龋的研究进展

背景:平滑面早期牙釉质龋虽然已发生脱矿改变但无肉眼可见的龋洞形成,目前临床采用的常规检测方法难以对其准确诊断.目的:应用光学相干断层成像技术对平滑面早期牙釉质龋的量化研究进展进行综述.方法:由第一作者检索CNKI和EBSCO HOST数据库中1979/2011发表的关于光学相干断层成像技术定量研究平滑面早期龋的相关文献,以"光学相干断层成像,早期龋,平滑面,量化评估"和"optical coherence tomography,early caries,smooth surface,quantitative assessment"为检索词进行检索.纳入31篇进行综述.结果与结论:新兴的光学相干断层成像技术能够检测龋变牙釉质的背向散射信号使脱矿牙釉质成像,并应用深度、反射率、衰减系数等定量指标对平滑面早期牙釉质龋进行量化评估,为牙釉质早期龋的诊断提供了新的方法.     

基于光学相干断层成像量化评估平滑面早期牙釉质龋的研究进展

背景：平滑面早期牙釉质龋虽然已发生脱矿改变但无肉眼可见的龋洞形成,目前临床采用的常规检测方法难以对其准确诊断。目的：应用光学相干断层成像技术对平滑面早期牙釉质龋的量化研究进展进行综述。方法：由第一作者检索CNKI和EBSCO HOST数据库中1979/2011发表的关于光学相干断层成像技术定量研究平滑面早期龋的相关文献,以＂光学相干断层成像,早期龋,平滑面,量化评估＂和＂optical coherence tomography,early caries,smooth surface,quantitative assessment＂为检索词进行检索。纳入31篇进行综述。结果与结论：新兴的光学相干断层成像技术能够检测龋变牙釉质的背向散射信号使脱矿牙釉质成像,并应用深度、反射率、衰减系数等定量指标对平滑面早期牙釉质龋进行量化评估,为牙釉质早期龋的诊断提供了新的方法。     

多乐氟氟保护漆对乳牙釉质脱矿和再矿化效果的实验研究

目的体外评价多乐氟氟保护漆对乳牙早期龋的脱矿和再矿化效果。方法离体乳牙标本80例,分为多乐氟组、5%氟化钠溶液组及人工唾液对照组,利用p H-循环模型在乳牙标本上形成人工龋,然后进行脱矿-再矿化循环处理,比较三组釉质表面钙释出率、乳牙牙釉质显微硬度及牙釉质表面氟含量的变化。结果多乐氟组乳牙釉质表面钙释出率明显低于5%氟化钠溶液组及人工唾液组,再矿化后的显微硬度、表面氟含量明显高于5%氟化钠溶液组及人工唾液对照组,差异均有统计学意义(P0.05)。结论多乐氟可明显抑制乳牙早期龋脱矿,促进其再矿化。     

含氟纳米氟磷灰石糊剂修复人工釉质缺损

背景：纳米氟磷灰石糊剂涂敷法可在人牙齿表面生长出类似牙釉质的柱状晶体。目的：观察1mg/L人体安全浓度的氟离子对纳米氟磷灰石糊剂修复人工釉质缺损的影响。方法：将人工早期釉质缺损样本随机分成两组,分别在样本表面涂敷添加含氟的纳米氟磷灰石糊剂（实验组）与不加氟的纳米氟磷灰石糊剂（对照组）,置于37℃水浴孵箱中修复。反应前后对牙齿表面行扫描电镜观察,晶体结构分析,化学成分鉴定和韦氏显微硬度测试。结果与结论：经处理后,两组样品表面都可见有一层与牙釉质化学组成和晶体结构类似的晶体生成,但实验组牙釉质样品表面结晶度、韦氏显微硬度明显高于对照组样品（P〈0.05）,且实验组牙釉质样品表面更光滑。结果表明,人体安全浓度含氟纳米氟磷灰石糊剂可明显提高人工釉质龋显微硬度、结晶度和表面光滑度。     

含氟纳米氟磷灰石糊剂修复人工釉质缺损

背景:纳米氟磷灰石糊剂涂敷法可在人牙齿表面生长出类似牙釉质的柱状晶体。目的:观察1mg/L人体安全浓度的氟离子对纳米氟磷灰石糊剂修复人工釉质缺损的影响。方法:将人工早期釉质缺损样本随机分成两组,分别在样本表面涂敷添加含氟的纳米氟磷灰石糊剂(实验组)与不加氟的纳米氟磷灰石糊剂(对照组),置于37℃水浴孵箱中修复。反应前后对牙齿表面行扫描电镜观察,晶体结构分析,化学成分鉴定和韦氏显微硬度测试。结果与结论:经处理后,两组样品表面都可见有一层与牙釉质化学组成和晶体结构类似的晶体生成,但实验组牙釉质样品表面结晶度、韦氏显微硬度明显高于对照组样品(P<0.05),且实验组牙釉质样品表面更光滑。结果表明,人体安全浓度含氟纳米氟磷灰石糊剂可明显提高人工釉质龋显微硬度、结晶度和表面光滑度。     

酪蛋白磷酸肽-磷酸钙溶液对牙釉质再矿化的影响

背景:酪蛋白磷酸肽-磷酸钙的作用时间和效力均强于普通只含钙磷的再矿化液,实验室及人体研究证明其能使牙釉质缺损再矿化,但研究多集中于釉质表面的微脱矿.目的:拟通过酸蚀剂处理形成不同深度的釉质表面脱矿形态,观察酪蛋白磷酸肽-磷酸钙溶液对牙釉质再矿化的影响.设计、时间及地点:对照观察实验,于2008-05/07在兰州大学口腔医院完成.材料;离体牙釉质块收集于兰州大学口腔医院外科门诊需拔除的正畸上颌第一前磨牙20个.方法:选取需拔除的正畸上颌第一前磨牙20个,随机分为2组,每组10个,分别用35%磷酸凝胶、20%磷酸凝胶对牙冠颊、腭面酸蚀处理60s,每颗牙牙冠沿近远中向纵剖,一半置于酪蛋白磷酸肽-磷酸钙再矿化液中矿化10d,另一半作为对照置于去离子水中.比较两种材料酸蚀及再矿化后的形态改变.主要观察指标:扫描电镜观察牙釉质表面在酸蚀后和酪蛋白磷酸肽-磷酸钙液再矿化后的表面形态改变.结果:采用35%磷酸凝胶、20%磷酸凝胶酸蚀后形成深、浅两种不同釉质酸蚀表面结构,呈鱼鳞状,经酪蛋白磷酸肽-磷酸钙再矿化液处理后酸蚀釉质表面都有大量的矿化物沉积,颗粒细小,沉积不均匀,逐渐变平,两种结构间无明显区别.结论:实验表明酪蛋白磷酸肽-磷酸钙可促进脱矿釉质再矿化,再矿化程度与釉质表面形态无关.     

光学相干层析成像技术对光滑面早期牙釉质人工龋的定量检测

背景:光学相干层析成像技术是一种高分辨率、非创伤性成像技术,它能够利用近红外光产生牙体组织的深度解析图像,并通过检测背向散射信号来对龋损进行定量检测.目的:通过与偏振光显微镜的对比,验证光学相干层析成像技术对光滑面早期釉质龋的成像能力及对龋损深度定量检测的准确性.方法:以6岁龄牛下切牙为样本,采用pH循环法建立光滑面早期龋人工模型,分别应用全光纤光学相干层析成像技术和偏振光显微镜进行检测,比较两种方法获得龋损图像和深度值,进行方差分析和相关性分析.结果与结论:光学相干层析成像系统能够清晰成像光滑面早期龋,表层下脱矿区域信号显著增强,并且测得的脱矿深度值与偏振光显微镜结果一致, 即该系统对深度的测量具有较高的准确性,可用于对早期龋纵深进展的评估.光学相干层析成像技术测得的人工龋模型开窗区的深度值与脱矿时间无相关性(P > 0.05).计算开窗区平均深度值与开窗区外平均深度值的差值即深度变化值(△D),则△D与脱矿时间呈正相关(r=0.954,P < 0.05).结果提示了这种无创、高分辨率的光学成像技术在早期龋的定量研究和临床诊断方面具有广阔的应用前景.     

氟化物防龋研究进展

早期龋的发生是牙釉质脱矿与再矿化交替进行的动态过程。氟化物被公认是有助于牙齿生长、矿化、降低牙齿的溶解度 ,从而起到抗龋作用的最为有效的物质。几十年来 ,国内外学者对氟化物抗龋机制进行大量研究后发现 ,氟化物的抗龋作用主要表现在对牙齿、唾液界面上发生的脱矿和再矿化作用的影响[1] 。唾液中低浓度的氟就足以使导致龋病发生的脱矿过程向再矿化转变 ,而再矿化过程的发生主要是由于氟化物增强了磷酸钙的沉积及釉质组织中氟磷灰石的形成。本文综合近年来的研究资料 ,对氟化物的防龋机制及其在龋病预防中的应用作一综述。1　氟化物…     

没食子对牙釉质矿化作用的体外实验研究

目的研究没食子对牙釉质的矿化作用,探讨没食子防龋的临床价值。方法应用离体牛牙制备人工釉质龋标本120颗,随机分为脱矿组和再矿化组各60颗,每组再分为氟化钠组、没食子组、去离子水组各20颗,分别进行脱矿和再矿化实验,行光敏荧光技术及扫描电镜检查,比较各组脱矿后及再矿化后荧光量及扫描电镜结果。结果荧光结果显示,在脱矿及再矿化实验中,没食子组和氟化钠组药物作用前后荧光量的比值比较差异无统计学意义(P>0.05),与去离子水组比较差异均有统计学意义(P<0.05);扫描电镜显示,没食子组和氟化钠组牙面均有颗粒附着,效果接近,去离子水组牙面无颗粒附着。结论没食子对离体牙釉质有再矿化、抗酸脱矿作用,对预防龋病发生有一定作用。     

In vitro study of the Nd:YAG laser effect on human dental enamel: optical and scanning electron microscope analysis

OBJECTIVE: The Nd:YAG laser irradiation of dental enamel was evaluated in enamel demineralization experiments in a Streptococcus mutans culture media. SUMMARY BACKGROUND DATA: Previous studies had shown that a continuous wave Nd:YAG laser at an energy of approximately 67 mJ may induce an increased acid resistance in human dental enamel when exposed to severe demineralization conditions. METHODS: Enamel windows of 3 x 4 cm in the buccal surface were irradiated with a continuous wave Nd:YAG laser at a wavelength of 1,064 microns using energy densities of from 83.75 to 187.50 J/cm2. Enamel windows of 3 x 4 cm on the lingual surface served as control (without the laser irradiation). The enamel windows were then exposed to a Streptococcus mutans culture media at a temperature of 37 degrees C for 15 and 21 days. The laser effects and demineralization were examined both by optical microscopy and scanning electron microscopy (SEM). RESULTS: A comparison between the lased and the unlased windows of enamel showed fusion and recrystalization of the enamel and increased acid-resistance in all groups irradiated with the Nd:YAG laser. On the other hand, the 3 x 4 delimited enamel surfaces from the control group (not irradiated with the Nd:YAG laser) showed 100% demineralization. CONCLUSIONS: These findings are consistent with the finding that laser irradiation of dental results in significant reduction of the effective solubility of enamel mineral.     

氟保护漆预防牙釉质脱矿的效果评价

背景:近年来在正畸治疗中产生牙釉质脱矿的副作用受到了越来越多的关注.尽管采取了各种方法和试剂,治疗效果尚不统一.目的:观察在牙齿正畸治疗过程中氟保护漆对牙釉质脱矿的保护效果.设计、时间及地点:对比观察,病例来自2006-01/2009-01解放军济南军区青岛第二疗养院口腔中心正畸科.对象:入选固定矫治患者132例(856颗牙),男56例,女76例,年龄7～18岁,平均年龄10.5岁.所有参与者牙体硬组织均发育良好,无四环素牙、氟斑牙、无牙体充填物,对治疗签订知情同意书,接受牙面处理和定期复查.方法:将实验对象随机分成实验组和对照组.实验组的牙齿安装粘托槽是使用氟保护漆,并每3个月重涂1层,而对照组和实验组操作基本相同,只是不使用氟保护漆.正畸治疗结束后,拆除矫治装置,对所有牙齿进行清洁抛光,观察记录数据.主要观察指标:两组正畸治疗后牙釉质脱矿的检出率.结果:实验组牙釉质脱矿发生率为5.51%,对照组釉质脱矿发生率为15.1%,使用氟保护漆后牙釉质脱矿发生率明显降低.结论:牙齿正畸治疗过程中使用氟保护漆对牙釉质脱矿有较好的保护效果.     

Acquired acid resistance of dental hard tissues by CO2 laser irradiation

OBJECTIVE: This investigation was performed to evaluate the effect of CO2 laser irradiation on the acquired acid resistance of dental hard tissues to artificial caries-like formation and the ultrastructure of lased areas was morphologically investigated in vitro. SUMMARY BACKGROUND DATA: In recent years, many studies have been carried out to evaluate the effect of the CO2 laser on the enhanced resistance to artificial caries formation of enamel. However, a limited number of papers concerning its effect on dentin have been published. METHODS: A CO2 laser of 10.6 microns wavelength was used to irradiate human enamel and dentin samples from 20 extracted human molar teeth, and samples were subjected to 2 microliters of 0.1 M lactic acid solution (pH 4.8) for 24 h at 36 degrees C. The parts per million (ppm) of calcium ion (Ca2+) dissolved in each solution was determined by atomic absorption spectrophotometry and the morphological changes were investigated by scanning electron microscopy (SEM). RESULTS: The lowest mean Ca2+ ppm was recorded in the samples irradiated at 3 W, followed by 2 W, 1 W, and unlased samples. SEM observation showed that the lased areas were melting with solidification of the smear layer. Even after acid demineralization, the lased surfaces were almost unchanged. CONCLUSIONS: The results of this study suggested that CO2 laser irradiation could sufficiently melt and solidify the enamel and dentin surfaces and thus enhance resistance to artificial caries-like formation.     

无创渗透树脂材料修复早期乳牙邻面龋

背景：乳牙早期邻面龋因解剖位置的原因菌斑不易去除,常规再矿化治疗疗效不佳。目的：观察无创渗透树脂技术治疗乳牙早期邻面龋的临床疗效。方法：选择乳牙邻面早期龋的患牙120颗,随机分为渗透树脂组和流动树脂组,每组60颗,分别应用渗透树脂和流动树脂进行治疗,治疗后1年随访,对患者邻面龋的牙体形态、去除釉质脱矿造成的白垩色斑和色泽稳定性、继发龋和治疗成功率方面进行临床评价。结果与结论：两组患者在充填治疗后1年的疗效检查结果中发现,渗透树脂组邻面龋的牙体形态、去除釉质脱矿造成的白垩色斑以及色泽稳定性、继发龋方面均好于流动树脂组。渗透树脂组的治疗成功率96．7％远高于流动树脂组的76.7％,差异有显著性意义（P〈0．05）。无创渗透树脂材料是目前阻断龋病发展简便高效的方法。     

Luminescence quantum yields of sound and carious dental enamel

The absorption and emission spectra of slabs of human and bovine dental enamel were determined. The absorption and scattering coefficients and emission quantum yields were computed according to theoretical models. The samples were gradually demineralized. The absorption, scattering, and emission parameters were determined as a function of the demineralization time. Using the theoretical models combined with the experimental values, ratio of the visible and UV luminescence, and the decrease of visible emission intensity upon demineralization are explained.     

Local axis orientation mapped by polarization sensitive optical coherence tomography provides a unique contrast to identify caries lesions in enamel

Due to rod-like hydroxyapatite crystal organizations, dental enamel is optically anisotropic, i.e., birefringent. Healthy enamel is known to be intrinsically negatively birefringent. However, when demineralization of enamel occurs, a considerable number of inter-crystallite spaces would be created between the crystallites in the enamel, which could lead to a sign reversion in birefringence of the enamel structure. We propose that this sign reversion can be leveraged in polarization sensitive OCT (PSOCT) imaging to differentiate early caries lesions from healthy enamel. In this study using PSOCT, we first confirm that the change in birefringence sign (negative to positive) can lead to a 90-degree alteration in the local axis orientation because of the switch between the fast and slow optic axes. We then demonstrate, for the first time, that the local axis orientation can be utilized to map and visualize the WSLs from the healthy enamel with a unique contrast. Moreover, the sharp alteration in local axis orientation gives a clear boundary between the WSLs and the healthy enamel, providing an opportunity to automatically segment the three-dimensional WSLs from the healthy enamel, enabling the characterization of their size and depth information in an intuitive way, which may aid clinical decision making and treatment planning.     

Varnish XT和ICON渗透树脂对釉质龋白斑微硬度的影响

背景：早期龋的治疗方法中,可以采用氟化物对龋白斑进行再矿化处理。长效释氟玻璃离子保护膜（Varnish XT）和ICON渗透树脂是两种新型的材料,Varnish XT是一种新型的树脂加强型玻璃离子,可以作为再矿化材料的新选择。ICON渗透树脂是一种流动性较好的高渗透系数树脂,借助毛细作用渗入到脱矿釉质的微孔中,利用低黏性的渗透树脂取代由于脱矿而丧失的硬组织并占据微孔的空间,填补釉质脱矿区并阻止病损的进一步发展。目的：观察Varnish XT和ICON渗透树脂两种微创治疗材料对釉质龋白斑微硬度的影响。方法：选择牛门齿100颗,将唇面向下作为观察面,环氧树脂包埋,打磨。暴露至少6 mm×10 mm的釉质牙面,由切端至颈部依次分A,B,C,D,E 5个区,E区用抗酸指甲油封闭。分别采用人工龋脱矿液后,A区不做处理,B区经Varnish XT处理,C区经ICON渗透树脂处理,D区经氟化物处理后,用韦氏硬度仪测量表面显微硬度值。结果与结论：脱矿样本经处理后A,B,C,D区的表面显微硬度值较E区均明显降低（P 〈0.05）, B,C,D区样本表面显微硬度值均较A区升高,且表面显微硬度值C区〉B区、D区（P 〈0.05）;B区的表面显微硬度值与D区相比,差异无显著性意义（P 〉0.05）。说明ICON渗透树脂、Varnish XT和氟化物对龋白斑的微硬度都有明显的改善,ICON渗透树脂的改善较Varnish XT和氟化物明显,Varnish XT和氟化物之间无明显差异。     

Multispectral near-IR reflectance and transillumination imaging of teeth

NIR imaging methods do not require ionizing radiation and have great potential for detecting caries lesions (tooth decay) on high-risk proximal and occlusal tooth surfaces and at the earliest stages of development. Previous in vitro and in vivo studies at 1300-nm demonstrated that high contrast reflectance and transillumination images could be acquired of caries lesions on tooth proximal and occlusal surfaces where most new decay is found. Water absorption varies markedly between 1200 and 1600-nm and the scattering properties of enamel and the underlying dentin have not been characterized in this region. Hyperspectral reflectance studies show lower reflectivity from sound enamel and dentin at NIR wavelengths with higher water absorption. The purpose of this imaging study was to determine which NIR wavelengths between 1200 and 1600-nm provide the highest contrast of demineralization or caries lesions for each of the different modes of NIR imaging, including transillumination of proximal and occlusal surfaces along with cross polarization reflectance measurements. A tungsten halogen lamp with several spectral filters and a Ge-enhanced CMOS focal plane array (FPA) sensitive from 400 to 1600-nm were used to acquire the images of caries lesions on extracted teeth. Artificial interproximal lesions were created on twelve tooth sections of 5 & 6-mm thickness that were used for transillumination imaging. Fifty-four extracted teeth with suspected occlusal lesions were also examined in both occlusal transillumination and reflectance imaging modes. Cavity preparations were also cut into whole teeth and filled with composite and used to compare the contrast between composite and enamel at NIR wavelengths. NIR wavelengths longer than 1400-nm are likely to have better performance for the transillumination of occlusal caries lesions while 1300-nm appears best for the transillumination of proximal surfaces. Loss of mobile water in enamel markedly reduced the transparency of the enamel at all NIR wavelengths. Significantly higher contrast was attained for reflectance measurements at wavelengths that have higher water absorption, namely 1460-nm. Wavelengths with higher water absorption also provided higher contrast of composite restorations.