电化学人工釉质龋和早期光滑面釉质龋组织病理学比较

为进一步研究电化学人工龋模型和龋病的关系，我们采用生物显微镜和扫描电子显微镜等手段，对体外形成的电化学人工釉和早期光滑面釉质龄的组织病理学进行了对比观察。结果表明电化学人工釉质龋在生物显微镜下和早期光滑面釉质龋一样形成以表层下脱矿为主要特征的病理改变，电化学人工釉质龋在扫描电子显微镜下主要表现为釉柱的釉柱的核心脱矿溶解，这亦和早期光滑面釉质龋相似。因此本研究结果提示二者有着十分相似的病理特点和病变     

ICON渗透树脂修复人工釉质龋白斑的效果研究

目的：评价ICON渗透树脂修复人工釉质龋白斑的效果。方法：选取因正畸而拔除的前磨牙28颗,制备人工釉质龋后,随机分为实验组和对照组,实验组采用ICON渗透树脂修复人工釉质龋白斑,对照组采用涂氟处理,测量并比较釉质龋白斑修复后的表面微硬度和龋白斑面积减少百分比,最后采用SPSS17．0软件进行统计分析。结果：治疗修复后实验组釉质龋的表面微硬度值显著高于对照组,差异具有统计学意义（P＜0．05）;修复后实验组龋白斑所占面积百分比低于对照组,差异具有统计学意义（P＜0．05）。结论：ICON渗透树脂能提高人工釉质龋白斑表面的微硬度,并能大大降低龋白斑的面积百分比,推荐临床使用。     

龋齿研究的物理模型

物理模型是一种常用的科学研究方法,也贯穿于龋病研究的始终。龋病研究的物理模型广泛应用在龋病病因、病理及影响因素等的分析研究中。人工龋实验、细菌致龋实验和人工口腔生物膜模型等在龋病发病机制的研究中发挥了十分重要的作用,本文就这些研究作一综述。     

OCT检出面窝沟早期人工龋的形态学比较研究

目的：探讨光学相干断层成像技术（OCT）检测窝沟早期人工龋的可行性。方法：利用pH循环法建立面窝沟早期龋模型,对其进行OCT扫描,获取二维伪彩图。在扫描路径所在位置制作牙磨片,进行偏光显微镜检测,获取其组织学图像。将二者所获取的图像进行形态学比较分析。结果：面窝沟健康牙釉质表面呈现一条光背向散射增强带,脱矿后牙釉质表面光反射和背向散射信号增强,光背向散射增强带厚度增加,光背向散射增强带下光信号迅速衰减。OCT检测出的龋损形态及深度与偏光显微镜下的组织学检测结果相符。结论：OCT可灵敏准确地检出人牙窝沟早期龋。     

含氟牙膏对釉质脱矿影响的体外研究

目的：探讨国内常见市售含氟牙膏对完整釉质及脱矿釉质的作用。方法：测定市售的3种含氟牙膏的氟含量,并选取釉质完好的牛牙及人工龋脱矿的牛牙,用3种含氟牙膏和不含氟牙膏刷洗釉面后,乳酸处理1min,用原子吸收光谱仪测定溶出的钙量。结果：含氟牙膏组和不含氟牙膏组均能使完整奥质的溶钙量明显降低,与空白对照组相比差异有显著性;含氟牙膏组和不含氟牙膏组均能使人工龋脱矿釉质的溶钙量明显下降,并且两组间有显著性差异。结论：含氟牙膏可以增强完整釉质及人工龋脱矿釉质的抗酸溶钙能力,且效果与其氟浓度相关,氟浓度为52.63umol/L时可显著提高牙齿抗酸力。     

Biomimetic remineralization of artificial caries dentin lesion using Ca/P-PILP

ObjectiveTo assess the ultrastructural change of demineralized dentin collagen during calcium phosphate polymer-induced liquid precursor (Ca/P-PILP) mediated remineralization process and to evaluate the biomimetic remineralization potential of high concentration Ca/P-PILP at demineralized artificial caries dentin lesion, additionally to investigate the bond interfacial integrity as well as the bonding strength of the biomimetic remineralized artificial caries dentin lesion.MethodsDemineralized dentin collagen of 5 μm thick was biomimetically remineralized with low, medium concentration Ca/P-PILP for 10 days and high concentration Ca/P-PILP for 10, 15, 20 days. Artificial caries dentin lesion at a thickness of 150 ± 50 μm was biomimetically remineralized with high concentration Ca/P-PILP for 20 days. The biomimetic remineralization of demineralized dentin collagen was observed by scanning electron microscopy (SEM). The biomimetic remineralization intensity and depth of artificial caries dentin lesion was assessed by Electron Probe Micro Analyzer (EPMA). The bonding interfacial integrity between remineralized artificial caries dentin and composite resin was observed by Swept-source optical coherence tomography (SS-OCT) and the bonding strength of remineralized artificial caries dentin was evaluated by micro-tensile bond strength analysis (μTBS).ResultsSolely PAA-PASP solution and solely saturated Ca/P solution can’t achieve dentin collagen remineralization. Increased concentration of Ca/P-PILP and prolonged remineralization time can enhance the biomimetic remineralization intensity of demineralized dentin collagen. After treating with high concentration Ca/P-PILP, a 150 ± 50 μm thick layer of demineralized artificial caries dentin lesion was not fully remineralized, and the biomimetic remineralization intensity reached up to 88.0%. Furthermore, a better bonding interfacial integrity with less microgap and increased bond strength at both baseline level and aging level were observed when artificial caries dentin lesion was biomimetically remineralized with high concentration Ca/P-PILP.SignificanceBiomimetic remineralization of demineralized caries dentin lesion promotes its clinical properties for resin composited adhesive restoration.     

氯化镧对人牙釉质人工龋的影响──扫描电镜、电子探针分析

借助体外人工龋方法从形态和内部结构变化上探讨了氯化镧（Ｌａ３＋）对人牙釉质龋的影响。磨片光镜下显示Ｌａ３＋预处理阻抑龋病发展的作用不如氟化钠（Ｆ－），但Ｌａ３＋与Ｆ－先后预处理能明显减轻龋损程度。扫描电镜观察发现Ｌａ３＋及Ｆ－预处理均能在牙面形成覆盖物，但以Ｌａ３＋与Ｆ－先后预处理产生的覆盖物较致密且与牙面结合较紧密。电子探针分析显示Ｌａ３＋处理后釉质表层内钙（Ｃａ２＋）含量明显减少，而Ｌａ３＋显著增加，表明Ｌａ３＋能与Ｃａ２＋发生离子交换反应而进入釉质。这种牙面覆盖物的形成及Ｌａ３＋－Ｃａ２＋交换反应可能是Ｌａ３＋预处理能防龋的关键之一。     

两种探针探诊牛牙人工早期龋对釉质的影响

目的:比较5 号尖探针和CPI探针探诊牛牙人工早期龋对釉质的影响.方法:采用体外酸蚀法构建牛牙人工早期龋的离体模型;通过定性、定量研究比较2 种探针探诊牛牙人工早期龋对釉质的影响.结果:扫描电镜发现,5 号尖探针探诊牛牙人工早期龋形成的探孔窄而深,CPI探针探诊牛牙人工早期龋形成的探孔宽而浅. CPI探针探诊对釉质产生的应变能大于5 号尖探针产生的应变能,两者之间的差异有统计学意义(Z＝-2.021,P=0.043),但由于二者的应变能值是在同一等级范围内,所以2 种探针对牛牙人工早期龋釉质的影响差异无实际意义.结论:5 号尖探针探诊牛牙人工早期龋对釉质的破坏并没有明显大于CPI探针.建议龋齿的流行病学调查和临床检查仍可以使用5 号尖探针,应避免采用较重的力去探诊,减少对釉质结构的潜在影响.     

Confocal laser scanning microscopic analysis of the depth of dentin caries-like lesions in primary and permanent teeth

This study analyzed comparatively, by confocal laser scanning microscopy (CLSM), the depth of caries-like lesions produced by biological and chemical artificial models in permanent and primary dentin. Six primary molars and six premolars were used. The occlusal enamel was removed and a nail polish layer was applied on the specimens, except for a 4 x 2 mm area on dentin surface. Half of specimens were immersed in acid gel for 14 days (chemical model) and the other half was immersed in BHI broth with S. mutans for 14 days (biological model). After development of artificial caries, the crowns were longitudinally sectioned on the center of the carious lesion. Three measurements of carious dentin depth were made in each specimen by CLSM. Measurements depths were compared between the caries models and between tooth types by one-way ANOVA and Tukey test (a=5%). For permanent teeth, the biological model showed significantly higher (p<0.05) caries depth values than the chemical model. For primary teeth, no statistically significant difference (p>0.05) was found between the caries models. The artificial caries model influenced caries depth only in permanent teeth. There was no difference in carious dentin depth between permanent and primary teeth, regardless of the artificial caries model.     

蜂胶防龋作用的研究

目的：探讨北京蜂胶提取物的防龋效果及其可能的了防龋机制，方法：选40个颊面正常的离体前磨牙分为5组，采用连续培养变形链球菌形成“人工龋损”的方法，比较蜂胶水溶液（5g/L,1.25g/L)、蜂胶醇溶液（1.5625g/L)、洗必泰（1．6g/L)、去离子水（对照）处理后所形成的人工龋损的深度及脱矿量。结果：蜂胶醇溶液组和蜂胶水溶液组处理过的牙的龋损深度比对照组变浅，脱矿量明显减少（P＜0．05），5g/L蜂胶水溶液组人工龋损深度和脱矿量在所有实验组中最低。结论：北京蜂胶提取物有很好的防龋效果，在龋病的预防中有较高的开发价值。     

酪蛋白磷酸肽-磷酸钙溶液体外再矿化作用的化学分析及显微硬度测试

目的研究酪蛋白磷酸肽-磷酸钙溶液在体外对牛牙釉质早期人工龋的再矿化作用。方法用不同浓度的酪蛋白磷酸肽-磷酸钙（CPP—CP）溶液对牛牙釉质早期人工龋进行再矿化处理后，首先采用化学分析法测量处理液中的残余矿物质，得出沉积在龋损区内的矿物质含量；然后采用显微硬度法测量处理前后牙釉质剖面硬度变化。结果CPP—CP溶液可以在体外使龋损牙釉质发生再矿化，再矿化作用与CPP—CP浓度呈剂量-效应关系。再矿化后龋损区矿物沉积量与再矿化液的CPP—CP浓度成正比。结论酪蛋白磷酸肽-磷酸钙溶液能凭借高钙磷浓度梯度促进牛牙釉质早期人工龋的再矿化。     

Remineralizing effects of glass ionomer restorations on adjacent interproximal caries

The purpose of this study was to examine the in vitro remineralization of incipient caries lesions on teeth adjacent interproximally to teeth with Class II glass ionomer cement restorations. Sixty-four extracted molars were selected and 1 x 5 mm artificial caries lesions were created at the interproximal contact point. One hundred micrometer sections were obtained at the caries sites, and polarized-light photomicrographs were obtained. The sections were covered with varnish, leaving only the external section site exposed, and were placed back into the original tooth. In another sixty-four molars, Class II cavities were prepared. Equal numbers of preparations were filled with Fuji IX GP, Vitremer, Ketac-Molar, or Z 250. These sixty-four teeth were mounted to have interproximal contact with the adjacent teeth containing the artificial caries lesions. Specimens were placed in closed environments of artificial saliva for one month. After thirty days, the same sections were photographed again under polarized light, and areas of the lesions were quantitated. Decrease in the size of caries lesions indicated the glass ionomers had significantly greater remineralization effects on adjacent caries than the nonfluoridated composite resin (ANOVA p < 0.05). There were no significant differences among the three glass ionomers tested.     

吃糖频率与龋齿病变进展的关系

目的：研究吃糖频率与龋病发病及进展的关系，并提出防治建议。方法：据离子动力学平衡理论，分析在偏光显微镜下人工龋的摄相。结果：通过比较相同外环境（模拟吃同类含糖食品后，口腔细菌代谢产生的有机酸）、相同时间（模拟每天食物残渣留在牙上未刷牙的总时间）、不同频率（模拟每天进食次数不同且都未刷牙）形成的人工龋，证实吃糖频率越高，牙齿损坏越严重。结论：吃含糖食物或进餐次数越频繁，每次食后又未清刷牙上食物残渣，致使口腔细菌代谢产生有机酸而易使龋齿病变进展。故牙齿保健应在食后数分钟之内刷牙或至少以清水漱口及纠正儿童频繁进食以防龋。     

Imaging artificial caries on the occlusal surfaces with polarization-sensitive optical coherence tomography

Polarization-sensitive optical coherence tomography (PS-OCT) is a nondestructive imaging system that can utilize near-infrared (IR) light to produce depth-resolved images of dental enamel and has the potential to monitor early enamel occlusal caries. The objective of this study was to investigate the relationship between the magnitude of backscattered light and depolarization recorded by PS-OCT with changes in the enamel mineral volume in an artificial caries model. Artificial lesions were created on a selected region on the occlusal surfaces of sound posterior teeth (n=10) using a well-characterized 14-day pH cycling model. An all-fiber-based PS-OCT system operating at 1,310 nm was used to collect serial images at day 0 and day 14 prior to tooth sectioning. The quantitative mineral content profile and relative mineral loss, DeltaZ (%volxmicrom), of the carious enamel samples were obtained from transverse sections using high-resolution digital microradiography (DM). Line profiles of PS-OCT and DM images were used to evaluate the artificial caries severity and depth. The integrated reflectivity of the perpendicular-axis PS-OCT image, quantifying lesion severity, was correlated to the DeltaZ of the caries lesions. There was also a strong correlation between the lesion depth calculated from both imaging modalities. PS-OCT can image and quantify artificial occlusal caries by measuring the increase in backscattering and depolarization of near-IR light. This optical method has promising applications for in vivo detection and monitoring of early enamel occlusal caries.     

Proteolytic phenomenon in enamel caries]

The proteolytic phenomenon in enamel caries has been investigated from three directions.Three kinds of proteolytic enzymes,papain,trypsin and collagenase have been used for treating enamel both in vitro and in vivo to observe their effect on the development of artificial enamel caries and demineralization of upper central incisors of thirty young persons.The results showed that the depth of the artificial caries was not increased after enzyme treatment.The calcium content of the demineralizing solution is also not increased after enzyme treatment.when the enamel powder of human beings was treated at first by natural plaque fluid and then by demineralizing liquid,no difference was observed between the data of experimental and control groups.Therefore,the results of this study does not support Gottleib's proteolytid theory of caries,especially in case of enamel ones.     

氟化物与镧、钼协同应用抑制牙釉质脱矿过程的研究

目的 :明确氟化物与镧、钼协同应用的防龋效果 ,为其应用研究提供实验依据。方法 :体外建立人工龋模型 ,氟离子、镧离子、钼离子分别应用及协同应用预处理后形成的人工龋 ,经扫描电镜和显微硬度测量研究表明 ,氟与钼、镧协同应用预处理形成的牙釉质人工龋 ,其脱矿深度较用同样浓度单独含镧、钼或氟预处理液处理者浅 ,釉质脱矿最轻 ,形成的人工龋深度最浅。釉质表面形成的覆盖物最厚、致密 ,呈块状和片状结晶 ,晶粒大、与下方釉质结合紧密。显微硬度高 ,它在抗酸实验中显示了较强的抗酸性。协同应用的防龋机理亦被探讨。结论 :氟、钼、镧协同应用防龋效果最好     

Utilization of laser fluorescence to monitor caries lesions development in primary teeth

PURPOSE: The objective of this study was to analyze and evaluate laser fluorescence (LF) performance in monitoring and quantifying smooth-surface incipient caries lesions in primary teeth. METHODS: Artificial caries lesions were produced in 2 delimited windows on the buccal surface of 24 primary incisors using a pH-cycling procedure. LF (DIAGNOdent) readings were collected on the windows on each tooth surface before (sound enamel) and after (artificial caries lesions) the demineralization process. The left lesion of each tooth was used for the polarized light microscopy analysis. Statistical tests were performed to observe the performance of the method and correlation between LF readings and caries lesions depth. RESULTS: There was a significant increase in the LF readings after demineralization (P < .0001). The area under receiver operating characteristic curve was 0.956, showing a good result of the method. The best cut off LF value to detect incipient caries was 5, and with this value, sensitivity, specificity, and accuracy was 0.78, 1, and 0.89, respectively. Pearson's correlation coefficient between DIAGNOdent values and caries lesion depth was 0.68. CONCLUSIONS: Although LF was good at detecting artificial caries lesions in primary teeth, the quantification of mineral loss was undesirable.     

Histopathology of the initial lesion of the root surface: an in vitro study

An acidified gel system was used to produce artificial caries lesions in root surfaces. Radiopaque surface layers were found with 47% of the lesions. Demineralized bodies of the lesion and mineralized zones of banding were seen in all lesions when examined by microradiography. Cementum and dentin seemed to respond to the acid attack in a similar manner. Although artificial root lesions did not simulate natural root caries entirely, the acidified gel system resulted in a reproducible method that might give insight into initial lesion formation on root surfaces. This technique may be used for studying the physico-chemical process involved in the demineralization of root surfaces and for testing the effects of various agents in the prevention of root caries.     

龋病发病机理的生物电化学理论（电化学人工龋模型的实验研究）

为进一步证实生物电和电化学机理在龋病发病中的作用，作者以电化学方法制造了人工龋模型的实验。结果证明：用电化学方法可制造出深达牙本质层且更加近似自然龋的类龋洞。这种类龋洞用现有化学方法是不能从牙釉质表面制造出来的。本研究为龋病发病的生物电化学理论，提供了依据。     

Penetration ability and microleakage of a fissure sealant applied on artificial and natural enamel fissure caries

OBJECTIVES AND METHODS: This study investigated the sealing ability of a current available unfilled fissure sealant applied over sound (n=80), artificially created (n=80) and naturally carious fissures (n=80) under different humidity conditions (90+/-2 and 45+/-2% relative humidity) and etching times (40 and 60s). All samples were submitted to 5000 thermal cycles and examined by light microscopy after sectioning. Microleakage, penetration ability, fissure type, fissure entrance angle, sealant occlusal length, caries location and caries depth were assessed. RESULTS: The significantly longer sealant occlusal length and larger entrance angle exhibited by shallow fissures, contributed to their higher microleakage and smaller amounts of unfilled areas compared to deep fissures. Sealant microleakage was significantly influenced by the condition of the enamel (sound, artificial and natural caries) and the caries location in the fissures, but not by enamel caries depth (D1 and D2), etching time, or humidity condition. Natural caries exhibited significantly higher microleakage than sound or artificially created carious fissures. CONCLUSIONS: Based on the results of this study, it can be concluded that location of caries in the fissure rather than its depth should be taken into account when applying a fissure sealant. When the borders of the fissure sealant are on carious enamel, a significantly higher microleakage must be expected. The artificial caries model was not a suitable method to assess the behavior of natural fissure caries.