马尾松针提取物抑制根面牙本质脱矿的理化性能研究

目的 研究不同浓度马尾松针提取物（PMNE）对牙本质脱矿的理化性能影响,为PMNE抑制根面龋的研究提供实验依据。方法 将离体牙根部牙体组织块分别放到去离子水（DDW）、氟化钠（NaF）、4%PMNE、8%PMNE及12%PMNE等5个组,每组10个试件（n=10）。在37℃条件下,各组试件经实验溶液、酸性缓冲液（pH5.0）和中性缓冲液（pH7.0）组成的pH循环,一天3次,共8天。用显微硬度计测定脱矿前后的牙体表面显微硬度差值（△SMH）,电感耦合等离子体原子发射光谱仪测定并计算酸性缓冲液中的钙离子释出率（CDR）。结果 PMNE组CDR均显著低于DDW组,显著高于NaF组（P<0.05）,且8%PMNE组CDR显著低于4%PMNE组（P<0.05）;各PMNE组△SMH均显著低于DDW组（P<0.05）,且8%PMNE组△SMH略高于NaF组,但无统计学意义（P>0.05）,两者均显著低于4%和8%PMNE组。结论 PMNE溶液可抑制根面牙本质脱矿,减缓其表面硬度的降低,且8%浓度组效果较佳。     

马尾松树皮和葡萄籽提取物对牙本质耐酸脱矿作用影响的比较研究

目的:评价马尾松树皮提取物(PMBE)和葡萄籽提取物(GSE)对根面牙本质耐酸蚀脱矿作用的影响.方法:表面一半被覆盖的根面牙本质块40个,被随机分为4组(n=10),分别用去离子蒸馏水(DDW)溶液、0.1％NaF溶液、12％ PMBE溶液和12％ GSE溶液作为实验溶液,进行为期8d的pH循环(实验溶液,酸性缓冲液和中性缓冲液).显微CT测定各组未脱矿侧和脱矿侧牙本质的矿物密度(dentin mineral density,DMD),场发射扫描电镜观察各组pH循环后牙本质表面显微形貌.结果:牙本质的矿物密度显示DDW组脱矿侧和未脱矿侧牙本质矿物密度差(△DMD) 198.64±59.97,NaF组为45.94±24.21,PMBE组为90.23±28.77,GSE组为105.07±29.53.PMBE组和GSE组△DMD均高于NaF组(P＜0.05),低于DDW组(P＜0.05),两者相互之间无显著差异(P＞0.05).扫描电镜见DDW组牙本质表面牙本质小管完全开放,NaF组牙本质小管基本封闭,PMBE组和GSE组牙本质小管口成梭形或狭长微裂隙开口.结论:PMBE和GSE均能提高牙本质的耐酸蚀脱矿作用.     

葡萄籽提取物促进早期牙本质龋损再矿化作用的体外研究

目的评价葡萄籽提取物（GSE）对人工牙本质龋的再矿化作用和显微结构的影响。方法制备60个人牙本质标本,采用化学法形成人工牙本质龋损,将样本随机分为4组,分别用10%GSE溶液、1 mg/L NaF溶液、10%GSE+ 1 mg/L NaF溶液和去离子水（DDW）处理,进行体外pH循环。采用显微硬度计测定处理前、后各样本的显微硬度值,扫描电镜观察pH循环后各组牙本质显微结构的变化,并用X线能谱仪分析牙本质元素百分含量。采用SPSS17.0软件包对数据进行统计学分析。结果显微硬度结果显示,GSE组牙本质的显微硬度获得百分比（SMHR）为40.87±9.92,NaF组为44.60±12.48,GSE+NaF组为48.54±9.27,去离子水组为15.98±8.33。与去离子水组相比,3个实验组的SMHR值均显著提高（P<0.05）,但相互之间无显著差异。扫描电镜显示,GSE组、NaF组和GSE+NaF组牙本质小管大部分呈封闭状态,而去离子水组牙本质小管呈开放状态。元素分析结果显示,3个实验组的Ca、P百分含量均显著高于去离子水组（P<0.05）。结论GSE能显著促进人工牙本质龋的再矿化作用,抑制牙本质龋的进展。     

不同生物活性玻璃对脱矿牙本质再矿化作用的比较研究

目的    体外评价不同生物活性玻璃对脱矿牙本质的再矿化作用。方法    收集2020年11—12月于郑州大学第一附属医院口腔颌面外科因阻生拔除的第三磨牙40颗，并制作成牙本质块。将脱矿处理后的牙本质块随机分为4组，每组10个，分别使用BioMinF®（BioMinF®组）、奥敏清®（奥敏清®组）、奥敏清®+氟化钠（奥敏清®+氟化钠组）、氟化钠（氟化钠组）处理，进行8 d的pH循环。使用扫描电镜和X射线能谱分析各组牙本质表面形态，以及BioMinF®和奥敏清®粉末的形态特征和元素组成。通过Micro-CT测定牙本质矿物质密度（dentin mineral density，DMD），并计算各组再矿化前后矿物质损失量（∆DMD）。结果    扫描电镜下可见BioMinF®粉末和奥敏清®粉末均呈不规则块状；X射线能谱分析示BioMinF®和奥敏清®均含有大量钠、硅及钙元素，此外，BioMinF®含少量氟元素。扫描电镜下可见4组再矿化区牙本质表面均有不同程度的阻塞物沉积，其中奥敏清®+氟化钠组表面沉积物最多，牙本质小管完全堵塞。各组再矿化前∆DMD总的比较，差异无统计学意义（F = 1.849，P = 0.156）。再矿化后∆DMD依次为：氟化钠组> BioMinF®组>奥敏清®组>奥敏清®+氟化钠组，其差异有统计学意义（F = 11.923，P < 0.001）；其中，除BioMinF®组和奥敏清®组的再矿化后∆DMD差异无统计学意义（P > 0.05）外，其他各组间再矿化后∆DMD比较，差异均有统计学意义（均P < 0.05）。结论    BioMinF®与奥敏清®均可能具有抑制牙本质脱矿和促进牙本质再矿化的作用，奥敏清®与氟化钠联合使用效果更佳，生物活性玻璃与氟化物在促进牙本质再矿化方面可能具有协同作用。     

酪蛋白磷酸肽-无定形磷酸钙对牙本质粘接界面耐pH循环老化的影响

目的 研究局部应用酪蛋白磷酸肽-无定形磷酸钙（CPP-ACP）对牙本质粘接界面耐pH循环老化的影响。方法 常规制备牙本质粘接试件,将其随机分为3组,其中2组行pH循环,期间每日分别加用CPP-ACP、去离子蒸馏水（DDW）处理,15 d后测定微拉伸粘接强度,观察断裂模式、界面形貌及纳米渗漏,并确定混合层内元素含量。另一组试件制备完成后即刻测试。结果 无pH循环组及pH循环/CPP-ACP组微拉伸粘接强度差异无统计学意义,但二者均显著高于pH循环/DDW组（P＜0.05）。试件均以混合破坏为主。pH循环/CPP-ACP组混合层质量优于pH循环/DDW组,纳米渗漏少。无pH循环组及pH循环/CPP-ACP组混合层内Ca含量显著高于pH循环/DDW组,Ag含量显著低于pH循环/DDW组（P＜0.05）。结论 牙本质粘接界面局部应用CPP-ACP可增强界面耐pH循环老化的能力,延缓界面退变。     

奥乐V护牙剂对早期釉质龋再矿化作用的研究

目的 观察奥乐V护牙剂对早期釉质龋的再矿化作用。方法 将50个牛牙釉质块建立人工龋模型后随机分为5组：奥乐V护牙剂组、GC护牙素组、氟化钠（NaF）组、奥乐V护牙剂+NaF组、去离子水（DDW）组,分别进入 pH循环模型。采用显微硬度计测定各组标本脱矿前和pH循环后的釉质表面硬度值,扫描电镜观察各组再矿化后釉 质表面形态结构的改变。结果 各实验组经再矿化处理后其表面显微硬度均明显提高（P<0.001）,奥乐V护牙剂组再矿化后其表面显微硬度低于NaF组（P<0.001）,但与GC护牙素组间差异无统计学意义（P>0.05）;再矿化后奥乐V护牙剂组釉质表面有较大颗粒沉积。结论 奥乐V护牙剂具有促早期人工釉质龋再矿化的作用。     

中药五倍子提取物对牙本质表面性能的强化作用

目的:评价中药五倍子对牙本质抗酸作用及表面强化的影响。方法:45个牛牙本质标本随机分为3组,以4 g/L五倍子提取液为实验药物,1 g/L NaF为阳性对照组,去离子水为阴性对照组,同时进行体外pH循环致龋实验。采用显微硬度仪测定各样本pH循环前后表面显微硬度,观察牙本质显微硬度的变化,并用扫描电镜和X线能谱仪分析pH循环后各组牙本质表面形貌和元素含量。数据采用SPSS17.0软件包进行统计学分析。结果:与去离子水相比,4 g/L五倍子可以显著减少牙本质表面显微硬度的降低(P<0.05),效果与1 g/L NaF无显著差异(P>0.05)。五倍子组和NaF组牙本质小管大部分呈闭合和堵塞状,而去离子水组牙本质小管呈开放状。五倍子组和NaF组的Ca和P成分显著高于去离子水组(P<0.05)。结论:五倍子可增强牙本质表面的抗酸能力,强化牙本质的表面性能,有抑制牙本质龋进展、保护牙本质免受酸腐蚀的作用。     

氟对脱矿和再矿化牙釉质表面的影响

目的研究氟对脱矿和再矿化牙釉质表面的影响,探讨氟防龋的作用机理。方法将牛牙釉质标本分为空白对照组（A组）、非氟化组（B组）、低氟化组（C组）和高氟化组（D组）4组,其中低氟化组和高氟化组依次进行氟化实验、脱矿实验和pH循环再矿化实验,非氟化组只进行脱矿实验和pH循环再矿化实验,空白对照组不做处理。在体视显微镜、显微硬度计和扫描电镜下观察各组釉质表面的形态变化,同时测量分析釉质表面显微硬度。结果氟化牙釉质的表面微观形态显著不同,其脱矿损害具有相对完整的表层;氟化组在氟化、脱矿和再矿化后与非氟化组相比,表面显微硬度均有统计学差异（P<0.05）。结论氟化牙釉质可增强牙釉质的抗龋能力和再矿化效能。     

宿主来源的基质金属蛋白酶对根部牙本质胶原的降解作用

目的观察根部牙本质中的基质金属蛋白酶（MMP）对牙本质胶原的降解作用.方法将脱矿的根部牙本质粉离心、冷冻干燥后分7组,每组6份,每份50.0 mg.各标本中分别加入1ml含不同成分的人工唾液,根据成分不同分为2 mmol/L4-乙酰氨基苯汞（APMA）组（MMP活化剂）;2、100、200 mmol/L乙二胺四乙酸（EDTA）组,0.2%、0.02%醋酸氯己定组（MMP抑制剂）;以空白人工唾液作对照组.37℃4 h后,用羟脯氨酸试剂盒测定各标本的胶原降解量.扫描电镜观察脱矿及脱矿后置于人工唾液中的根部标本表面结构变化.结果APMA组的胶原降解量最多,其次为对照组,两者间差异有统计学意义（P＜0.05）.各MMP抑制剂组的胶原降解量均显著少于APMA组和对照组,差异有统计学意义（P＜0.01）.扫描电镜结果表明,仅脱矿的根部表面胶原纤维较完整;而脱矿后置于人工唾液中的标本胶原纤维断裂,结构紊乱.结论脱矿过程中的低pH值能使根部牙本质中的MMP活化,在中性时可降解牙本质胶原.提示宿主来源的MMP可能是龋病进展过程中有机质破坏的重要原因之一.     

酪蛋白磷酸多肽-无定形磷酸钙在正畸治疗中预防牙釉质脱矿的体外研究

目的通过体外实验研究酪蛋白磷酸多肽-无定形磷酸钙（CPP-ACP，商品名护牙素）对固定矫治中托槽周围牙釉质脱矿的预防作用。方法将60颗因正畸治疗而拔除的前磨牙随机分成四组：①护牙素组：②0．2％NaF组；（劲，2％NaF＋护牙素组；④空白对照组。在牙齿颊面粘结正畸托槽，体外pH循环35天后，每组取10个样本经切片、磨片至厚度100μm～110μm，采用软X线投照技术及高清晰度数码显微图像分析系统测量釉质脱矿深度和灰度。另外，每组取5个样本用扫描电镜观察釉质表面超微结构的改变。用SPSS13．0统计软件进行数据处理分析。结果形态学表现：软x线照片显示护牙素组、0，2％NaF组、0．2％NaF＋护牙素组都没有出现明显脱矿，对照组出现了19．34&#177;6．8μm深的脱矿。扫描电镜显示前三组的牙釉质表面有矿物质沉积，孔隙变小，对照组的牙釉质表面有程度不等蜂窝状孔隙。灰度值比较结果显示：①护牙素组、0．2％NaF组之间脱矿量没有统计学差异（P〉0．05）；②护牙素组、0．2％NaF组、0．2％NaF＋护牙素组的脱矿量与空白对照组之间有显著的统计学差异（P〈0．05）；③护牙素组及0．2％NaF组与0．2％NaF＋护牙素组之间均有显著的统计学差异（P〈0．05）。结论护牙素在正畸治疗中具有预防牙釉质脱矿作用；护牙素和氟化物有协同作用，可增强牙齿的防龋能力。     

Effect of fluoridated milk on enamel and root dentin demineralization evaluated by a biofilm caries model

Although some studies suggest an anticaries effect of fluoridated bovine milk (F-milk) on enamel, evidence is still considered weak. Even more uncertain, the effect of F-milk on root caries remains largely unknown. This study evaluated the effect of F-milk on enamel and on root dentin demineralization using a validated Streptococcus mutans biofilm model, simulating a high cariogenic challenge. S. mutans (UA159) biofilms were formed on bovine enamel and root dentin saliva-coated slabs after measuring initial surface microhardness (SH). Biofilms were exposed to 10% sucrose 8×/day and treated 2×/day with either: (1) 0.9% NaCl (negative control), (2) bovine milk, (3) F-milk (5.0 ppm F as NaF) or (4) NaF 0.05% (anticaries-positive control). Medium pH was monitored twice/day, as a biofilm acidogenicity indicator. After 5 days for enamel and 4 days for dentin, biofilms were recovered to analyze: biomass, soluble proteins, viable microorganisms, and extra- and intracellular polysaccharides. Enamel and dentin demineralization were estimated by percentage of SH loss. Results were compared by ANOVA and Tukey's test. Neither acidogenicity nor biofilm composition differed among treatment groups in biofilms formed on enamel or dentin (p > 0.05). F-milk, however, significantly reduced enamel and dentin demineralization when compared with the negative control (p < 0.05). Also, F-milk was as efficient as 0.05% NaF to reduce enamel (p > 0.05), but not dentin demineralization (p < 0.05). These findings suggest that milk containing 5.0 ppm of fluoride is effective to control enamel caries and that it may be effective on root dentin caries prevention.     

Effect of nano-carbonate apatite to prevent re-stain after dental bleaching in vitro

Objectives

This study examined the effect of nano-carbonate apatite (n-CAP) to prevent re-staining and the change of enamel surface after dental bleaching in vitro.

Methods

Twenty-four bovine specimens were bleached for 2 weeks with 10% carbamide peroxide (CP). After bleaching, the specimens were divided into the following four groups: distilled and deionized water (DDW, negative control), 10% n-CAP, NaF (positive control) and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP, positive control). Each group was subjected to pH cycling for 7 days. The specimens were treated for 4 min 3 times per day and re-staining was induced naturally by artificial saliva in the remineralization process. After pH cycling, the changes in colour were evaluated with spectrophotometry and scanning electron microscopy (SEM). The difference in colour between before and after pH cycling was evaluated using an ANOVA and Tukey test.

Results

After pH cycling, the colour difference of n-CAP group was significantly lower than that of the DDW and CPP-ACP groups (p < 0.05). SEM showed that n-CAP particles were deposited regularly on the damaged surface compared to the other groups.

Conclusion

10% n-CAP could significantly maintain the initial colour and protect the damaged enamel structure after bleaching.     

The effect of human saliva substitutes in an erosion–abrasion cycling model

Saliva may affect dental erosion–abrasion by reducing demineralization, enhancing remineralization, and acting as lubricant. This study tested the effect of human saliva substitutes in an erosion–abrasion cycling model designed for enamel and root dentin. Specimens were randomly assigned into the following groups (n = 8): artificial saliva (AS), artificial saliva + mucin (AS+M), deionized water (DIW, negative control), and pooled human saliva (HS, clinical reference). Each group was submitted to a cycle of 5 min in 1% citric acid (pH 3.75), 30 min in the testing solutions, and toothbrushing (enamel, 500 strokes; dentin, 150 strokes, ～200 g load) in fluoridated dentifrice (1,100 p.p.m. NaF) slurry. Specimens were rinsed and dried after each procedure. This cycle was repeated three times each day, for 3 d. Substrate loss was measured daily using optical profilometry. Analysis of variance (anova) and Tukey tests (α=0.05) showed a significant increase in enamel and dentin wear throughout the experiment for all groups. At the end of the experiment, enamel wear for each group was ranked as: (AS)<(AS+M) and (HS)<(DIW), with AS+M not differing from HS. For dentin, groups AS and AS+M did not differ from each other or from DIW, but showed significantly higher wear than HS. The artificial saliva with mucin showed promise as a potential substitute for human saliva in the enamel erosion–abrasion cycling model. For dentin, none of the artificial salivas performed similarly to human saliva.     

3种无氟儿童牙膏对乳牙早期釉质龋再矿化作用的体外研究

目的 探究3种市售无氟儿童牙膏即生物活性玻璃儿童牙膏、双黄连儿童牙膏、木糖醇儿童牙膏对乳牙早期釉质龋的再矿化作用。方法 应用离体乳牙制备人工龋模型50例,随机分为5组：活性玻璃组、双黄连组、木糖醇组、NaF组、去离子水组。在体外进行pH循环后,测量各组乳牙的表面显微硬度,并结合偏光显微镜对乳牙的釉质龋损进行形态学观察。结果 活性玻璃组能显著提高乳牙早期釉质龋再矿化后的表面显微硬度（P<0.05）,但其提高的程度不如NaF组（P<0.05）,双黄连组、木糖醇组和去离子水组未能提高再矿化后的显微硬度（P<0.05）。偏光显微镜下,活性玻璃组与NaF组再矿化后乳牙表层釉质的脱矿深度明显变浅。结论 生物活性玻璃儿童牙膏能有效促进乳牙早期釉质龋再矿化,但其再矿化能力小于含氟牙膏,双黄连儿童牙膏和木糖醇儿童牙膏在本次实验中未能体现出再矿化能力。     

Effect of an anticalculus dentifrice on lesion progression under pH cycling conditions in vitro

The aim of the present study was to examine a sodium fluoride anticalculus dentifrice product containing soluble pyrophosphate for its ability to promote remineralization and/or inhibit demineralization of dental enamel in a pH cycling model in vitro. Enamel crowns with windows were subjected to 14 days of alternating demineralization and remineralization periods at 37 degrees C. Teeth were immersed 5 min daily in one of the test dentifrice systems (1:3 slurry in deionized water) between the demineralization and remineralization cycles. Test dentifrices included (1) sodium fluoride (NaF; 1,100 ppm F)/silica abrasive (Crest) and (2) NaF (1,100 ppm F) with 3.3% soluble pyrophosphate/silica abrasive (Crest Tartar Control). Controls included a placebo dentifrice (silica abrasive) with no added fluoride and a group which received no treatment at all, i.e., demineralization/remineralization only. Overall, both of the NaF dentifrices were very effective in limiting in vitro caries progression and were not significantly different from each other. Inclusion of pyrophosphate in the NaF dentifrice did not affect the net outcome of the cycling demineralization/remineralization processes which is in agreement with recent clinical and in situ studies of these products.