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。     

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。     

The permeability of artificial dentine carious lesions

OBJECTIVE: This study aimed to verify whether two demineralisation solutions, with different fluoride concentrations, would produce subsurface lesions in dentine, as assessed by microradiography, with different mineral loss profiles and, subsequently, to determine the dentine permeability of the two altered tissues. METHODS: Forty-five human coronal portions were prepared and randomly divided into two test groups (20 specimens each) with the remaining five as a control group. Each test group was exposed to a demineralisation solution containing either 1 or 5 ppm fluoride for five days. RESULTS: There were highly significant differences between the two test groups for all microradiographic parameters, except for lesion depth. The increase in dentine permeability from baseline to day 5 was statistically significant within each of the two test groups, but not for the control group. CONCLUSION: The differences in the mineral content profile of the two lesions did not influence the magnitude of change in their permeability.     

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.     

A computer-assisted videodensitometric method to visualize mineral distributions in in vitro and in vivo formed root caries lesions

A computer-assisted videodensitometry (CAV) method is presented for the microradiographical mineral determination and mineral visualization of in vitro and in vivo formed dentin lesions. The method employs as essential steps (1) image digitizing by a CCD camera, (2) conversion of gray values to equivalent aluminium thicknesses and (3) conversion of aluminium thickness to vol% of mineral. Procedure and accuracy are described. The CAV method is illustrated for dentin lesions formed in vitro as well as for clinical root caries lesions. The CAV method is especially advantageous for clinical lesions because it can be employed for very complex mineral distributions and irregular lesion outlines. In given areas of interest, the mineral distribution (in vol%) can be plotted in 3D form in pseudo-colors. Conventional micro radio graphical profiles can be obtained directly from the CAV images. For in vitro lesions, the mineral distribution parameters, lesion depth, mineral loss, and mineral acquisition values can be generated from CAV images with a reproducibility of better than 7%. The CAV method is a valuable tool in quantitative mineral studies of clinical lesions in extracted teeth as well as in situ lesion investigations.     

Remineralization effects of gum arabic on caries-like enamel lesions

OBJECTIVE: Gum arabic is a natural polysaccharide exudate from Acacia senegal and other related African species of Acacia. Gum arabic is considered to have an ability to enhance remineralization, because of its high concentration of Ca(2+). However, the caries preventive capacity of gum arabic has been scarcely investigated. We evaluated the cariostatic activities of gum arabic using histopathological methods to determine its effects on remineralization. DESIGN: Following incubation in demineralization solution, human third molars were exposed to 10 mg/ml of gum arabic, sodium fluoride at 1000 ppm (NaF), or double distilled water (DW, negative control), then subjected to demineralization-remineralization cycles. Before and after demineralization-remineralization cycles, contact microradiographs of each sample were taken and mineral distribution quantities were calculated. RESULTS: The remineralization ratio of the molars exposed to gum arabic was similar to that of those exposed to NaF, while the ratios of both were significantly greater than that of those exposed to DW. CONCLUSIONS: Gum arabic enhanced the remineralization of caries-like enamel lesions in vitro, suggesting its inhibitory effects towards dental caries.     

牙颈部非龋性硬化牙本质粘接的超微形态研究

目的观察牙颈部非龋性硬化牙本质经自酸蚀牙本质粘接剂处理后，树脂一牙本质界面的超微结构。方法选择有典型牙颈部非龋性缺损且因牙周病拔除的上颌前磨牙，使用两步法的自酸蚀粘接剂Contax粘接处理。扫描电镜观察硬化牙本质表面超微形态以及树脂一牙本质界面的混合层和树脂突的微观表现。结果硬化牙本质的牙本质小管大部分被柱状的矿化结晶体堵塞。粘接界面也可见到清晰的混合层和树脂突，但树脂突较短。结论硬化牙本质的粘接与正常牙本质存在差异，牙本质小管内的矿化结晶可能影响粘接效果。自酸蚀粘接剂对硬化牙本质具有一定的粘接能力。     

牙体与充填体间微隙对微生物致龋影响的实验研究

目的 体外建立经变形链球菌致龋的人工龋模型,评价牙与充填体间微隙大小对微生物致龋的影响.方法 用无龋磨牙制备的牙块和形态大小相同的复合树脂块制作二者间隙分别为0、25、50、100、190及250 μm的6个实验组样本,对照组样本使用粘接剂粘接牙面和复合树脂,6个实验组及对照组每组各8个样本,共56个样本经14 d变形链球菌连续培养后切片,采用激光共聚焦扫描显微镜( confocal laser scanning microscope,GLSM)检测牙体洞外表面龋损及洞壁龋损的脱矿程度,分别测定龋损最大深度、最大长度、荧光面积及平均荧光量等参数并进行统计学分析;扫描电镜观察界面微隙内沉积物与龋损形成情况.结果 CLSM和扫描电镜观察显示,除2个对照组样本未形成洞壁龋损外其余样本均形成了不同程度的洞外表面龋损和洞壁龋损;各组表面龋损脱矿程度差异均无统计学意义(P＞0.05).190 μm组及250 μm组洞壁龋损最大深度[分别为(1145.37±198.98)、(1190.12±290.80)μm]、最大长度、荧光面积及平均荧光度均显著高于0、25、50及100 μm组[龋损最大深度分别为( 205.25±122.61)、(303.87±118.80)、(437.75±154.88)、(602.87±269.13)μm],差异均有统计学意义(P＜0.01),脱矿程度随微隙增加而加重;而0、25、50μn组洞壁龋损最大深度、最大长度及荧光面积差异均无统计学意义.结论 体外牙与充填体间的微隙大于100 μm时提示洞壁龋损有明显进展;微隙的存在是影响牙与充填体间微生物致龋的重要因素.     

Micromorphological and micronanalytical characterization of stagnating and progressing root caries lesions

Root caries is the predominant disease of the tooth tissues in the elderly population and differs in progression and micromorphology from coronal dentin caries. Therefore, different clinical concepts are needed for the treatment of these progressing and arrested lesions. It was the aim of this study to investigate the three-dimensional structure and volume of stagnating and progressing root caries lesions and to determine the mineral composition of the different lesion zones to achieve a better understanding of the natural history of root caries lesion formation. Of 21 extracted human teeth of patients between 42 and 77 years of age with stagnating and progressing root caries lesions serial sections were cut and investigated with polarized light and scanning electron microscopy. From the polarized light micrographs 3D reconstructions were made to determine the volumes of the lesion zones and their relations expressed in a demineralization index (DI). With increasing size of the demineralizing zone the DI increased indicating an increase in the size of the translucent zone. The 3D reconstructions showed distinct differences between stagnating and progressing root caries lesions. In the hypermineralized translucent dentin not all dentin tubules were obliterated by intratubular dentin and within the translucent dentin scattered dead tracts were found. Electron dispersive X-ray (EDX) analysis showed that the intertubular dentin of the translucent dentin was also demineralized to a certain extent. The results indicate distinct morphological differences between progressing and stagnating root caries lesions which may have consequences for treatment strategies.     

SEM and microradiographic investigation of initial enamel caries

Abstract – In this paper a combined microradiography and SEM study is presented on human enamel after a caries attack in vivo for a 4-wk period. The initial enamel caries is induced under a specially designed orthodontic band; plaque accumulation takes place under a niche in the band. The microradiography and SEM were done on the same sections. A special manipulation and breaking technique of the thin sections makes it possible to observe with the SEM, demineralized enamel areas with a mineral content known from microradiography. The results show that with a mineral content of about 50 vol. %, the observable porosity is noticeable at the prism level (interprismatically) but barely noticeable at the crystallite level. The surface morphology of the demineralized enamel is at low magnifications not very different from sound enamel. At high magnifications, however, the surface porosity becomes visible. The results indicate that the mineral in vivo losses in enamel after an initial caries attack can be explained mainly by mineral losses from interprismatic areas and from the prism peripheries.     

化学机械去龋对牙本质粘结效果的电镜观察

目的扫描电镜观察化学机械去龋对牙本质粘结效果的影响。方法观察比较化学机械去龋和慢速球钻去龋后牙本质表面以及牙本质和4种粘结系统粘结界面的超微结构。结果与球钻去龋相比，化学机械去龋后的牙本质表面玷污层少，牙本质和Prime＆Bond　NT（PB）＋复合体的粘结界面出现树脂突结构，和Adper　Prompt-L-Pop（AP）＋树脂的粘结界面中树脂突更密集，混合层更致密、均一。结论从超微结构上看，化学机械去龋技术有利于牙本质的粘结。     

Predicting development of approximal dentin lesions by means of past caries experience

The aim of this study was to assess the accuracy in predicting future development of approximal dentin lesions using radiographically observed numbers of restored and carious surfaces at age 13 as diagnostic criteria. ROC curve technique was applied employing the development of at least one new dentin lesion from age 13 to age 15 and 18 respectively, as validating criterion. Two groups of patients were considered, residing in communities with water fluoride content of 0.2 ppm and 1.2 ppm, respectively. Results showed that the development of dentin lesions could be predicted with an accuracy similar to that of many other dental radiographic procedures. This implies that it ought to be possible to use previous caries experience as a means of individualizing the scheduling of future radiographic procedures.     

Column-like structures of human dentin in carious and artificial lesions

Abstract— Serial sections of 36 human teeth with minor to medium-sized carious lesions, adequate sections from previous studies of artificial lesions adjacent to fillings of amalgam (AM), silicate cement (SI) and glass ionomer cement (GI) were studied by ordinary light microscopy and microradiography. Six artificial primary root lesions were included. In carious lesions, dentin columns were visible in the demineralization zone and partly also in the translucent/radiopaque zone. A typical feature of the artificial lesions adjacent to SI fillings was highly radiopaque columns alternating with radiolucent ones. In the GI group such columns were seen at the cavity wall and the advancing front of the outer lesion. In the AM group dark columns were unveiled as pegs in the latter localization. The findings led to the assumption that the dark columns of intact dentin are preferred pathways of acid diffusion in artificial and, possibly, carious lesions. Increased radiopacity of columns in the SI and GI groups is explained by continued exposure of the tooth surface to fluoride dissolved from these fluoride-rich filling materials.     

A structural analysis of approximal enamel caries lesions and subjacent dentin reactions

The present study examines the correlation between caries lesions in enamel and the corresponding dentin reactions in proximal tooth surfaces with lesions ranging from enamel lesions to cavitations without dentin exposure. Using quantitative imbibition technique, the highest degree of tissue porosity, irrespective of lesion activity, was always noted along a Central-Traverse (CT), which followed the direction of the rods from the deepest point of penetration to the surface. The conical shape of approximal enamel lesions can thus be seen as the result of systematic variations in porosity along the rods determined by the specific interproximal environment. The initial dentin reaction, related to the enamel lesion approaching the enamel–dentin junction (EDJ), was seen as a local dentin translucency where the CT crossed the EDJ. Results from histomorpho-metric analyses revealed that, when the enamel lesions reached the EDJ, brownish discoloration in the dentin never exceeded the histologic contact area between the enamel lesion and the EDJ. In relation to the less advanced parts of the individual enamel lesion, the dentin responded with formation of translucent dentin. These reactions did not occur beyond an area determined by lines in the direction of the rods from the peripheral part of the enamel lesion towards the EDJ. The results did not support the view that dentin caries spreads along the enamel-dentin junction. The peripheral dentin translucency is therefore generated by stimuli transmitted along the rods of the less advanced parts of the enamel lesions.     

Recovery after PILP remineralization of dentin lesions created with two cariogenic acids

ObjectivesAcetate and lactate are important cariogenic acids produced by oral bacteria. They produced different residual dentin structures in artificial lesions of similar depth. We evaluated if such lesions responded in the same way to a polymer-induced-liquid-precursor (PILP) remineralization.DesignDentin blocks obtained from human third molars, divided into 6 groups (n = 3). Blocks were demineralized with acetate (66 h) or lactate (168 h) buffer at pH 5.0 to create 140 μm target lesion depths. A-DEM and L-DEM groups received no remineralization. Other groups were remineralized for 14 days. 100 μg/mL polyaspartate was added into the remineralizing buffer for A-PIL and L-PIL, whereas A-CAP and L-CAP were treated with the same solution but without polyaspartate. Cross-sectioned blocks were examined for shrinkage and AFM-topography. Line profiles of reduced elastic modulus (E_r) were obtained by AFM-based nanoindentation across the lesion. Ultrastructures were examined with TEM.ResultsA-PIL and L-PIL recovered in shrinkage to the original height of the dentin and it appeared normal with tubules, with increases in E_r at both outer flat and inner sloped zones. At the sloped zone, acetate lesions lost more E_r but recovery rate after PILP was not statistically different from lactate lesions. A-CAP and L-CAP showed surface precipitates, significantly less recovery in shrinkage or E_r as compared to PILP groups. TEM-ultrastructure of PILP groups showed similar structural and mineral components in the sloped zone for lesions produced by either acid.ConclusionsThe PILP process provided significant recovery of both structure and mechanical properties for artificial lesions produced with acetate or lactate.     

Number of teeth, prevalence of caries and periapical lesions in insulin-dependent diabetics

Abstract – Ninety-four long and 86 short duration diabetics and 86 non-diabetics, aged 20–70 yr, participated in the study. The clinical and radiographic examination comprised recordings of the number of teeth, carious lesions, restorations, endodontically treated teeth and periapical lesions. There were no significant differences between long and short duration diabetics and non-diabetics in the number of teeth and the total number of decayed and filled tooth surfaces (DFS %). However, long duration diabetics exhibited more decayed proximal tooth surfaces (D %) than non-diabetics. There were no significant differences between long and short duration diabetics and non-diabetics in the mean number of endodontically treated teeth and periapical lesions. Women with long diabetes duration, however, exhibited more endodontically treated teeth with periapical lesions than women with short diabetes duration and women without diabetes. Long duration diabetics exhibited teeth with periapical lesions to a greater extent than the other groups. On the whole, diabetics and non-diabetics exhibited a similar caries frequency but among the diabetics there was a group of individuals who had more periapical lesions than the non-diabetics.     

乳牙釉质、牙本质磷含量之分析研究

目的:探讨乳牙釉质、牙本质磷元素和儿童龋病的关系。方法:对象为5～7岁38名(男17名,女21名)幼儿,取其因乳恒牙替换所拔除的正常下颌乳中切牙38颗(Ⅰ19颗,Ⅰ19颗)。用电子探针X线显微分析仪检测其釉质、牙本质在近中、远中、唇和舌侧之不同深度的磷含量。38名幼儿按其临床检查分为无龋组14名,有龋组24名。结果:①釉质舌侧、近中侧和牙本质各侧之不同深度间,磷含量均有非常显著性差异(P均<0.001),且牙本质深层磷含量高于浅层。②釉质、牙本质之磷含量在男女性别间无差异(P>0.05);在左右同名牙间亦无显著性差异(P>0.05)。③牙釉质和牙本质之磷含量在无龋组和有龋组间无明显差异(P>0.05)。有龋组之磷含量与dfs仅在牙本质浅层存在低度负相关关系(r=-0.41596,P=0.0432),其余均无相关性。结论:乳牙牙釉质和牙本质磷含量是有高度差异,但磷含量与患龋状况无相关性。     

The attitudes of parents toward the oral health of children and their reflection on the non-cavitated caries lesions

ObjectiveTo determine the extent of non-cavitated caries lesions in preschool children, and compare its relationship with socioeconomic status, oral and dental health practices, knowledge of caries prevention, and nutrition.Materials and methodsNinety-seven parents of 36–72 month-old children completed a questionnaire on the socioeconomic status of the family, parent's knowledge of caries prevention, the children's oral health practices, and nutrition. In the children, the cavitated dental caries were assessed according to World Health Organization (WHO) criteria and non-cavitated caries lesions on occlusal and smooth surfaces were evaluated by Universal Visual Scoring System (UniViSS). Statistical analysis was conducted using the SPSS software program. The relationships between variables were assessed using the chi-square test and logistic (ordinal) regression analysis.ResultsStatistically significant results were obtained relating to the parents' age, number of children, the time of first oral hygiene, frequency of tooth brushing, knowledge of caries prevention, drinks most often consumed by the children, and number of non-cavitated lesions. According to the regression model, the significant variables were caries activity (yes), drinks most often consumed by the children (milk–juice; juice–buttermilk), the frequency of tooth brushing (once a day, twice a day), observed changes in a child's teeth (change in color and breaks in teeth), the number of cavitated caries lesions and decayed, missing and filled teeth (dmft).ConclusionsThe primary factors contributing to non-cavitated caries lesions include the time of first oral hygiene and frequency of tooth brushing. The early diagnosis of non-cavitated caries is essential for preventive measures.     

3D激光扫描显微镜下牙本质龋微结构的观察和分析

目的 通过3D激光扫描显微镜观察牙本质龋的微结构,为临床上龋病的防治及相关研究提供形态学理论依据。方法 收集6颗新鲜拔除的有龋坏的第三磨牙,均制备成横剖面标本,在3D激光扫描显微镜下进行光学、激光彩色及3D形貌图的观察。结果 在样本整体结构中,光镜下可见病变组织的轮廓,激光彩色镜下较清晰分辨两层牙本质病变;在微结构中,激光彩色图下可以观察到透明层牙本质小管部分闭合,脱矿层管周和管间牙本质数目较少,细菌侵入层管周和管间牙本质均破坏,相邻小管融合,呈串珠样和椭圆形病灶,坏死崩解层无正常牙本质结构。3D形貌图下可根据颜色的不同观察到四层结构。结论 3D激光扫描显微镜能够分辨牙本质龋的两层病变组织结构,观察到牙本质四层结构中牙本质小管、管周、管间牙本质的不同改变,是观察牙本质微结构的有力工具。同时牙本质龋微结构的形态对临床上龋病的防治及相关研究具有理论指导意义。