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.     

五倍子提取液对实验性根面龋再脱矿作用的影响

目的：探讨中药五倍子提取液对实验性根面龋的抑制作用。方法：以50％五倍子提取液为实验药物,38％氟化双氨银[Ag（NH3）2F],2％氟化钠（NaF）为阳性对照,去离子水为阴性对照。测量实验性根面龋再脱矿中脱矿量与时间的关系及总矿物质损失量。结果：38％Ag（NH3）2F抑制脱矿作用最强,其余依次为50％五倍子提取液、2％氟化钠、去离子水。50％五倍子提取液与38％Ag（NH3）2F、2％氟化钠无显著性差异（P〉0．05）,各药物处理组与去离子水比较均有显著性差异（P〈0．01）。结论：50％五倍子提取液对Ca^2＋溶出量及总矿物质损失量具有显著的抑制作用,对Ca^2＋溶出量的抑制作用优于2％NaF。     

五倍子水提取物抑制人工牙本质龋矿物质溶出的实验研究

目的:探讨五倍子水提取物溶液对人工牙本质龋中矿物质溶出的影响.方法:人工牙本质龋标本经20 g/L氟化钠液、100mg/mL五倍子水提取物溶液、380g/L氟化双氨银液、去离子水分别处理后再置于混合致龋菌培养液中培养,采用自动生化分析仪分别于1、3、6、12、18、24、48 h检测混合菌液中的钙、磷离子浓度.结果:药物处理组钙、磷离子溶出量均显著低于对照组.五倍子水提取物溶液与380 g/L氟化双氨银液抗牙本质钙离子溶出的能力相当,均显著低于20 g/L氟化钠液(P<0.05).磷离子溶出量在药物处理组间也表现出明显差异.380 g/L氟化双氨银液组最低,五倍子水提取物溶液组最高(P<0.05).结论:五倍子水提取物溶液对牙本质龋中钙离子的溶出有抑制作用,提示其可增强牙本质的抗酸蚀能力,一定程度上抑制牙本质龋的进展.     

牙本质磷蛋白对牙本质再矿化的影响

目的　探讨牙本质磷蛋白 (dentinphosphoprotein ,DPP)与脱矿牙本质再矿化的关系。方法　 (1 )用氯化钠提取脱矿牙本质中的易溶性DPP并鉴定。 (2 )用氯化钠去除和未去除易溶性DPP的脱矿人牙根牙本质磨片 ,经再矿化后通过原子吸收光谱、扫描电镜和显微放射照相的观测比较两组再矿化程度。结果　 (1 )证明了 1mol/L氯化钠可以提取脱矿牙本质中的易溶性DPP ;(2 )去除和未去除易溶性DPP的磨片组相比再矿化液的钙离子浓度显著减少 (P <0 0 1 ) ;磨片上生成较多量的矿物质沉积 ;显微射线照片平均吸光度值显著降低 (P <0 0 1 )。结论　易溶性DPP对脱矿牙本质再矿化有明显的抑制作用 ,在根面龋的再矿化中去除易溶性DPP能提高其再矿化的潜能。     

牙周非手术治疗对根面牙本质敏感症形成的影响

目的：观察牙周非手术治疗对导致根面牙本质敏感症的影响，并探讨其机理。方法：对52例慢性牙周炎患者的1453颗牙进行龈下刮冶及根面平整术，随访3个月。总结冶疗后患者根面牙本质敏感症的发生情况。结果：52例患者中，39例共432颗牙发生了不同程度的根面牙本质敏感症，给予积极治疗后症状大多消失。龈下刮治术和根面平整术可使部分牙本质小管敞开暴露于口腔环境中，使外来刺激遵循液体动力学原理激发痛觉。结论：脱敏治疗应纳入牙周治疗计划中。     

基质金属蛋白酶-1对根面牙本质有机质降解作用的超微结构观察

目的　观察基质金属蛋白酶-1(MMP-1)对根面牙本质有机质的降解作用。方法　收集临床拔除的健康无 龋阻生牙,切取根颈1/3处约5 mm厚的牙体,制成牙本质组织块,随机分为4组。第1组用酸溶液脱矿处理21 d 后,放入MMP-1溶液中孵育7 d;第2组仅用酸溶液脱矿处理21 d;第3组仅用MMP-1溶液酶解7 d;第4组为正常牙 本质标本对照组,不作任何处理。将各标本切割制作样本,脱水干燥,喷金,扫描电镜观察。结果　酸和酶溶液共 同处理的标本牙本质硬组织脱矿明显,牙本质小管管腔失去原有形态,边界不清,周围暴露的胶原纤维断裂不连 续,排列杂乱不规则。酸或酶溶液单独处理组未发生明显的基质纤维降解现象。结论　内源性蛋白酶参与了根面 龋的发生发展过程,MMP-1能够明显降解脱矿后的牙本质有机质。     

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。     

氯化镧漱口水防治老年根面龋三年临床观察

目的:观察和评价氯化镧(LaCl3)漱口水防治老年根面龋的临床效果.方法:选择63～84岁患有牙龈萎缩根面暴露的老年人222名,随机分为实验组和对照组,每组均按常规方法记录牙龈退缩数和根面龋补数,实验组每日使用一次500×10-6mmol/L的含La3 漱口水漱口,对照组使用NaCl漱口水漱口,两组均使用1个月、1年及2年后重复使用漱口水1个月,3年后复查每个老年人根面龋情况.结果:实验组根龋指数(RCI)的新增值明显低于对照组.结论:500×10-6 mmol/L的含La3 漱口水能有效地控制老年根面龋.     

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。     

Human root caries: histopathology of initial lesions in cementum and dentin

The histopathology of human root caries was examined in extracted teeth by different optical methods. The present part of the study details the sequential stages of initial caries in both cementum and peripheral dentin. Significant differences are shown between the mechanisms operating on the various dental hard tissues during development of caries. Histologically distinguishable reaction patterns depended on both the degree of the cariogenic challenge and the respective structural features of cementum and peripheral dentin. Earliest lesions, histologically visible as small clefts traversing cementum and extending into peripheral dentin, were clinically not detectable. Cementum was stepwise destroyed until peripheral dentin became exposed. The exposed peripheral dentin was sclerosed and tubule-free. Demineralization of dentin preceded the degradation of the organic matrix. Frequently, a hypermineralized layer occurred in both cementum and exposed dentin. Its localization was not identical with the anatomical surface. Initial penetration of bacteria into peripheral dentin occurred along small clefts. Breakdown of the organic matrix was the final step in the destructive phase of the carious process.     

Inhibition of bovine dentin demineralization by a glutardialdehyde pretreatment: an in vitro caries study

Intact bovine dentin specimens were demineralized in 25 mmol acetic acid buffers (pH 5), with and without a 5-min pretreatment with an acidic 2% glutardialdehyde (GDA) solution. The results demonstrate that GDA inhibits dentin demineralization and that the inhibition depends strongly on the initial calcium and phosphate concentration in the demineralization solution. The observed inhibition increases from about 5% without calcium and phosphate to 38% with a calcium and phosphate concentration initially of 6.4 mmol and 4.1 mmol, respectively. The inhibition can be explained either by a reduction of calcium and phosphate diffusion out of the lesion or by the retention of mineral inhibitors in the dentin.     

The effects of a sodium hypochlorite treatment on demineralized root dentin

The effects of a 10% NaOCl treatment for 2 min on demineralized human root dentin were investigated by means of: microradiography (MR), scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) and secondary ion mass spectroscopy (SIMS). MR measurements revealed that NaOCl caused a tissue contraction not related to water loss but to removal of organic sub-stance(s), resulting in reductions of the lesion depth and mineral loss values by 15% and 42%, respectively. CLSM observations on wet dentin showed that the dentinal tubules underneath the surface are clearly observable and not deformed substantially by the NaOCl, except near the outermost surface. This indicates the importance of wet as well as of dried (high vacuum) observations. SEM micrographs (high vacuum) showed definite changes in the outer dentin surface structure, 85% of the originally open dentinal tubules were closed after NaOCl treatment. No marked changes were observed in the dentin ultrastructure inside lesions, as shown by SEM on fractured surfaces. SIMS data, pertaining to samples in high vacuum, showed a remarkable increase of chlorine (Cl) content in the entire lesion due to the NaOCl, indicating deep penetration of the original OC1 ions. The results suggest that the 2-min treatment of demineralized dentin by NaOCl solutions removes and/or changes part of the dentin matrix in nearly the whole lesion. As a consequence the mineral is somewhat redistributed, the outermost surface of a few μm is changed, but the main dentin structure and element composition are still intact. These findings indicate that NaOCl treatments are of interest in remineralization and hyperremineralization studies of dentin.     

Root and pulpal dentin after surface demineralization

Abstract Previous studies have indicated that there may be a difference in connective tissue response to surface demineralized dentin from root and pulpal surface regions. Consequently, it was the purpose of the present investigation to examine the initial surface characteristics of the dentin from these regions to determine if there were differences which could enhance interactions with adjacent connective tissues. Rectangular dentin specimens with opposite faces of root and pulpal region dentin were immersed in a saturated solution of citric acid, pH 1, for 3 min, rinsed, and prepared for examination in an ISI-40 SEM. Comparisons were made between root and pulpal surfaces of the specimens, and with non-acid treated controls. Control specimens were characterized by the presence of a smear layer which obscured the openings of dentinal tubules on all surfaces. Citric acid treatment removed the smear layer, resulted in exposure of dentinal tubule orifices, and produced a mat-like, fibrillar surface texture. The pulpal surface had a more coarse appearance than the root surface. Quantitation of the number and diameter of tubule orifices showed larger values for the pulpal surface. The percentage of die surface area occupied by tubule orifices was significantly greater on the pulpal aspect. It was concluded that surface demineralization of dentin from the pulpal region results in exposure of a greater amount of collagen substrate, and the latter may predestine an enhanced interaction with connective tissue components.     

Influence of glutardialdehyde on dentin demineralization in vitro and in vivo

Abstract – In this paper the results are presented on the action of glutardialdehyde (GDA) on the in vitro demineralization of human dentin and on the in vivo demineralization of dentin using the Ögaard orthodontic banding system. The results show that a 2 min application of a 2% GDA solution at pH = 3.6 reduces dentin demineralization in vitro and in vivo substantially. Microradiography shows a percentage reduction of lesion depth and mineral loss in vitro of 20 and 36%, respectively. After 2 wk in vivo demineralization the same percentage reductions are 60 and 44%, respectively. The mechanism of action of GDA on dentin is not certain yet. Presumably the in vitro action is due to surface cross-linking of the dentin matrix causing reduced Ca and phosphate transport out of the dentin. In vivo an additional effect may be a rather short term influence of GDA on plaque or on plaque accumulation. The results of this paper indicate that glutardialdehyde is an interesting agent to consider in the reduction of root caries.     

Molecular pathogenesis of root dentin caries

Human dentin has a higher content of organic matrix and more non-ideal hydroxyapatite than human enamel. Ultrastructural studies indicate that root caries involves both mineral dissolution and breakdown of the organic matrix. Factors involved in the root caries process seem more complicated than those in enamel caries. Moreover, the distinct roles of acids and enzymes and the sequence of events in the root caries process are not well-understood. Although Streptococcus mutans and Actinomyces viscosus are considered to be major pathogenic micro-organisms of root caries, their roles in degradation of the organic matrix components of root dentin need clarification. The purpose of this paper is to review the basic composition of root dentin and the roles of acids and both endogenous and bacterial enzymes in the root caries process.     

Effect of periodontal root planing on dentin permeability

Abstract The purpose of this study was to quantitate the effects of root planing on the permeability of human root dentin in vitro. Unerupted 3rd molars were used. The crowns were removed and longitudinal slices made of the root. The hydraulic conductance of the root dentin was measured before and after root planing, acid etching and potassium oxalate application using a fluid filtration method. The results showed that root planing creates a smear layer that reduces the permeability of the underlying dentin, However, this smear layer is acid labile, Thus, root planing may ultimately cause increased dentin permeability and the associated sequelae of sensitive dentin, bacterial invasion of tubules, reduced periodontal reattachment and pulpal irritation.