酪蛋白磷酸肽钙磷复合体对邻面去釉牙釉质再矿化的研究

目的:评价酪蛋白磷酸肽钙磷复合体对邻面去釉牙釉质再矿化的临床效果。方法:以正畸减数的双尖牙为实验样本30个,采用去釉砂条去釉和35%的磷酸抛光,随机分成A、B、C3组,A组应用酪蛋白磷酸肽钙磷复合体,B组应用氟保护漆,C组未处理为对照组,经体外PH循环20d后采用定量的显微硬度检测。结果:每2组的显微硬度值差异均有统计学意义。(P值分别小于0.05)其中A组最高;C组最低。结论:酪蛋白磷酸肽钙磷复合体对邻面去釉牙釉质具有很好的再矿化作用。     

氟化泡沫预防青少年固定正畸过程中釉质脱矿的临床研究

目的观察固定正畸过程中应用氟化泡沫对年轻恒牙形成釉质脱矿的影响。方法选取60例固定正畸患者（年龄11～14岁）,分为3组,分别采取3个月应用一次氟化泡沫,6个月应用一次氟化泡沫,及未使用氟化泡沫。记录治疗12个月后牙面的釉质脱矿指数（EDI）,计算平均EDI,进行统计学分析。结果 3个月应用一次氟化泡沫组平均EDI为0.144,明显低于其他两组,存在统计学差异;6个月应用一次氟化泡沫组平均EDI为0.256,与未使用氟化泡沫组平均EDI为0.350相比无明显统计学差异。结论 3个月应用一次氟化泡沫能有效预防固定正畸过程中年轻恒牙的釉质脱矿。     

牙釉质和牙本质核DNA在法医个人识别中的应用研究

目的评价牙釉质和牙本质核DNA在法医个人识别中的应用价值．方法从受外界理化因素和生物因素影响小的牙釉质、牙本质中提取核DNA,采集了20颗无关个体磨牙的牙釉质、牙本质用有机法提取核DNA．结果牙釉质、牙本质中能提取到理想的核DNA．结论牙釉质、牙本质中的细胞核DNA能用于法医个人识别,为实际案件的侦破提供重要证据．     

Influence of the irradiation distance and the use of cooling to increase enamel-acid resistance with Er:YAG laser

Objectives

The aim of this study was to assess the influence of irradiation distance and the use of cooling in the Er:YAG laser efficacy in preventing enamel demineralization.

Methods

84 enamel blocks were randomly assigned to seven groups (n = 12): G1: control group – no treatment, G2–G7: experimental groups treated with Er:YAG laser (80 mJ/2 Hz) at different irradiation distances with or without cooling: G2: 4 mm/2 mL; G3: 4 mm/no cooling; G4: 8 mm/2 mL; G5: 8 mm/no cooling; G6: 16 mm/2 mL; G7: 16 mm/no cooling. The samples were submitted to an in vitro pH cycles for 14 days. Next, the specimens were sectioned in sections of 80–100 μm in thickness and the demineralization patterns of prepared slices were assessed using a polarized light microscope. Three samples from each group were analyzed with scanning electronic microscopy. Analysis of variance and the Fisher test were performed for the statistical analysis of the data obtained from the caries-lesion-depth measurements (CLDM) (alpha = 5%).

Results

The control group (CLDM = 0.67 mm) was statistically different from group 2 (CLDM = 0.42 mm), which presented a smaller lesion depth, and group 6 (0.91 mm), which presented a greater lesion depth. The results of groups 3 (CLDM = 0.74 mm), 4 (CLDM = 0.70 mm), 5 (CLDM = 0.67 mm) and 7 (CLDM = 0.89 mm) presented statistical similarity. The scanning electronic microscopy analysis showed ablation areas in the samples from groups 4, 5, 6 and 7, and a slightly demineralized area in group 2.

Conclusions

It was possible to conclude that Er:YAG laser was efficient in preventing enamel demineralization at a 4-mm irradiation distance using cooling.     

The clinical application of surface pH measurements to longitudinally assess white spot enamel lesions

Objectives

Means of objectively assessing white spot enamel lesions (WSEL) are critical for determining their potential activity and monitoring the success of preventive treatments. The aim of this study was to determine whether surface pH measurements of WSEL changed during a preventive course of care designed to remineralize the lesions.

Methods

Eight healthy subjects (1 male and 7 females) with at least one WSEL were recruited (19–64 years). Each subject was placed on a preventive treatment program including the daily application of a CPP-ACP paste (MI paste, GC Corp., Japan) with custom fitted trays for more than 6 months. The surface pH values of sound enamel and WSEL were monitored for up to 2 years using a micro-pH sensor. The visual appearance of the WSEL was monitored via digital photography, and images were analyzed qualitatively on a 5-point scale to assess the success of the remineralization preventive program. The relationship between the qualitative assessment of WSEL appearance and the WSEL pH was investigated using a Spearman's rho non-parametric correlation.

Results

The surface pH of the WSEL was different to that of the sound enamel surrounding it in all patients at all times. All lesions showed visual improvement as the treatment period progressed. The pH of the WSEL increased towards that of sound enamel over the course of treatment significantly correlating with the visual improvement of the lesion (rho = 0.63, p < 0.0001).

Conclusions

The clinical assessment of WSEL surface pH changes with time may have utility as an additional objective measure for the assessment of WSEL activity.     

四种陶瓷材料与牙釉质磨耗性能的研究

【目的】研究临床常用的四种陶瓷材料（松风陶瓷、义获嘉陶瓷、低温水热陶瓷、纳米陶瓷）与天然牙釉质的磨耗性能,比较不同修复材料对天然牙釉质的磨耗,探讨其磨耗机制。【方法】采用针一盘式二体磨耗机,以滑石瓷为对磨物,计算天然牙釉质、陶瓷试件及其对磨滑石瓷的体积损失并电镜观察修复材料磨耗面的微观结构。【结果】被测试件磨耗后体积损失量均小于天然牙（P〈0．01）,天然牙体积损失量与其对磨滑石瓷体积损失量无显著性差异（P〉0．05）,松风陶瓷的滑石瓷损失量大于其它各组陶瓷（P〈O．01）,义获嘉陶瓷的滑石瓷损失量大于纳米陶瓷及低温水热陶瓷（P〈0．01）,纳米陶瓷与低温水热陶瓷的滑石瓷损失量无显著性差异（P〉0．05）。电镜观察不同修复材料磨耗后其磨痕及微观结构明显不同。【结论】修复材料的微观结构是影响其磨耗性能的重要因素,改善材料的微观结构可减少对天然牙的过度磨耗,保护牙齿硬组织。     

Enhancing attachment of human gingival fibroblasts to periodontally compromised teeth: A comparative analysis of hyaluronic acid,EDTA, enamel matrix derivatives

BackgroundGingival recession is a characteristic indicator of periodontitis and one of the factors that contributes to increased tooth clinical crown length. Patients with root exposure frequently undergo periodontal surgical procedures in addition to adjunctive therapy to increase root coverage area and soft tissue stability.PurposeThis study aimed to evaluate fibroblast-root surface adhesion and determine whether periodontitis-damaged root surface microstructure can be restored using ethylenediaminetetraacetic acid (EDTA) and an enamel matrix derivative (EMD), individually or in combination.Material and methodsTeeth extracted from patients with periodontal disease were used to create 60 samples, with each group containing six specimens. The test groups were provided root planing or root condition-specific materials (hyaluronic acid [HA], 24% EDTA, EMD, or EDTA/EMD) for varying treatment time periods. In contrast, the control group did not undergo any surface modifications. The samples and fibroblast cells were incubated for 72 h. The number of living cells on the root surface in each group was calculated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay (cell viability assessment).ResultsThe control, root planing, and EMD groups showed that the root surfaces treated with EDTA for 4 min had significantly better cell adhesion. Surface EDTA treatment for 2 min significantly promoted cell attachment compared to root planing treatment. The root surfaces modified with EDTA/EMD for 2 and 4 min showed significantly improved cellular migration and adhesion compared to the root surface treated with root planing.ConclusionEDTA and EDTA/EMD substantially affected the root surface, which was related to the length of the treatment process. This effect shifts the surface properties, alters fibroblast interactions with the root surface, and recruits more cells to cover a larger area.     

Fluoride uptake and acid resistance of enamel irradiated with Er:YAG laser

This study evaluated the resistance to demineralization and fluoride incorporation of enamel irradiated with Er:YAG. A total of 110 bovine teeth were selected and divided into eight groups: unlased, 37% phosphoric acid, and samples irradiated with the Er:YAG laser at several fluences (31.84 J/cm², 25.47 J/cm², 19.10 J/cm², 2.08 J/cm², 1.8 J/cm², and 0.9 J/cm²). The application of acidulated phosphate fluoride was performed after treatments. All samples were immersed in 2 ml of 2.0 M acetic–acetate acid solution at pH 4.5 for 8 h, and fluoride, calcium, and phosphorus ions dissolved were analyzed by atomic absorption spectrometry and spectrophotometry. The phosphoric acid and 31.84 J/cm² groups presented the lowest dissolution of calcium and phosphorus ions. Higher fluoride incorporation was observed on 1.8 J/cm² and 0.9 J/cm² groups. Based on these results, Er:YAG laser was able to decrease acid dissolution and increase fluoride uptake and can be a promissory alternative for preventive dentistry.     

Immunological reactions of the organic matrix of developing bovine enamel

Bovine amelogenin, the organic matrix secreted by the dental-enamel-forming cells, is antigenic in the rabbit. The purified gamma globulin fraction of the rabbit antisera when reacted with amelogenin in a double diffusion agar plate forms a single precipitin line. Subfractions isolated from amelogenin by acrylamide gel electrophoresis and by Sephadex gel filtration were found to be antigenically identical. The antigenic fraction of amelogenin was separated from the bulk of the enamel protein by a Sephadex G-100 column. On the basis of its electrophoretic and gel filtration properties, amelogenin is a multi-component system; however, immunologically, amelogenin acts as a single antigen.

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Zusammenfassung Rinder Amelogenin, die organische Matrix, welche durch die Zahnschmelz-bildenden Zellen sezerniert wird, wirkt als Antigen auf das Kaninchen. Die gereinigte Gammaglobulinfraktion des Kaninchen-Antiserums ergibt auf einer Doppel-Diffusions-Agarplatte eine einzelne Koagulinlinie, wenn sie mit Amelogenin reagiert.Unterfraktionen aus Amelogenin isoliert durch Acrylamid-Gel-Elektrophorese und durch Sephadex-Gel-Filtration wurden in ihrer Antigen-Wirksamkeit identisch gefunden. Die Antigen-Fraktion von Amelogenin wurde durch eine Sephadex G-100-Säule von der Gesamtmenge des Zahnschmelz-Proteins getrennt.Auf Grund seiner bei der Elektrophorese und der Gel-Filtration beobachtetem Eigenschaften ist Amelogenin ein aus verschiedenen Komponenten zusammengesetztes System; Amelogenin wirkt jedoch immunologisch als ein einzelnes Antigen.

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Résumé De l'amélogénine bovine, matrice organique secrétée par les cellules formant l'émail dentaire, est antigénique chez le lapin. La fraction purifiée de gamma-globuline de l'antisérum de lapin, en présence d'amélogénine, dans une boite d'agar à double diffusion, provoque une ligne simple de précipitine. Des fractions isolées de l'amélogénine, par électrophorèse sur gel d'acrylamide et par filtration sur gel de Sephadex, semblent identiques au point de vue antigénique. La fraction antigénique d'amélogénine est séparée de la protéine de l'émail à l'aide d'une colonne Sephadex G-100. L'amélogénine est un système complexe, si l'on se réfère aux résultats d'électrophorèse et de filtration sur gel: ai point de vue immunologique, l'amélogénine se comporte comme un antigène simple.

     

骨缺损自修复过程中骨质体积变化规律分析

骨骼自修复理论认为外荷载是骨骼重建的直接刺激源。本文介绍了骨缺损自修复过程的实验观测方法及相关观测结果。首先对兔子股骨开孔以破坏骨的连续性,建立骨缺损模型,然后利用CT扫描提取股骨数据,并用MIMICS软件来观测分析骨缺损后由生长因子引起的自修复过程,最后建立骨质体积变化关系,为仿生拓扑优化方法引入自修复机制提供科学依据。实验结果表明,在同样的条件下青年兔骨缺损部位各层骨质的修复比成年兔快得多,并且修复过程中软质骨与硬质骨体积变化之间存在着按一增一减的比例交叉变化的特性。