儿童专用牙膏

儿童的牙齿和口腔非常娇嫩，家长们在为孩子选购牙膏时，一定要购买专为孩子配制的儿童专用牙膏。根据儿童牙齿生长周期的特点，尤其是在儿童刷牙的过程中，可能会吞食一些牙膏，因此，家长在为孩子选购牙膏时，一定要与成人牙膏区别开来，要特别注意牙膏的成分和生产的专业性、专属性。     

中国牙协二氧化硅应用技术研讨会在湖南召开

中国牙膏协会二氧化硅应用技术研讨会于２００１年８月３１日至９月３日在湖南省张家界市召开。二氧化硅是一种新型牙膏磨料 ,不仅可以防止传统牙膏对牙齿的腐蚀作用 ,还可以增强膏体的稳定性和清洁性 ,提高牙膏的洁齿、护齿和健齿等功能。这种新型牙膏磨料由湖南晨光化工厂首家生产 ,并已形成了年产５０００ｔ的能力。与会专家以极大的兴趣参观了生产现场及其成品。会议对二氧化硅在牙膏生产中的应用进行了技术交流 ,并就一些问题进行了研讨和解决。会议指出 ,二氧化硅作为一种新型牙膏磨料 ,在我国推广应用条件成熟 ,技术可靠 ,前景看好。…     

儿童慎用含“氟”牙膏

含氟牙膏的防龋作用已经得到全世界公认。幼儿正处于牙齿发育的敏感期,尤其是恒切牙牙冠的形成期,含氟牙膏将帮助孩子远离龋齿,并在将来拥有一口健康漂亮的牙齿,其作用不可低估。然而,氟也是一把“双刃剑”低剂量对人体无生理作用,     

牙齿形成的化学机理及生化过程

介绍了牙齿的组成、结构及牙齿形成的化学机理，以及影响牙齿形成的因素；基质效应、细胞效应和基质器，对牙齿形成的生化过程作了介绍。     

牙齿修复材料的研究进展

随着经济发展和医疗水平的提高,全球人口老龄化的趋势日益加重,再加上饮食结构的不合理,牙齿损坏或缺失者逐渐增多,人们对牙齿修复材料的探索研究也就相应增多,本文对金属材料、树脂基复合材料以及陶瓷材料及相关技术进行了分类并进行了详细地阐述,对其应用于牙齿修复的部位进行了概括,并对未来的发展进行了分析。     

漱口舅 漱口防蛀香糖

漱口舅是美国JC公司投入巨资开发的全球首创的漱口防蛀型食品，含磨擦剂ISORUB，咀嚼时通 过磨擦牙齿(能感觉到模拟刷牙的沙沙声)彻底清洁牙齿和口腔：含防蛀成分lsomalt和XYLITOL，抑制牙菌斑和酸性物质生成，有效防止蛀牙：含天然植物提炼胶基，特别耐嚼：无糖低热量，食用者绝无发胖的困扰。 使用特点：孩子不会刷牙，嚼漱口舅吧! 据调查，我国有近95％的儿童患有蛀牙，为了让孩子学会刷牙坚持刷牙，父母伤透了脑筋，仍然无可奈何。只要每天坚持嚼漱口舅，就能帮助孩子漱口洁齿、防止蛀牙，同时还满足了孩子吃零食的嗜好，真是父母和孩子都满意。     

口腔卫生制品的发展

清洗牙齿和口腔的制品是用来除去牙齿表面的食物残屑，以防止形成牙斑和产生不良的气味，而大多数洁齿用品是为了减少牙齿龋蚀的发病数，是为了保持牙龈的健康。在讨论口腔卫生制剂的性能、作用和机理之前，值得提起的是：在1950年以前，所用的口腔卫生制剂的配制仅是作到清净牙齿的表面，增加美观，抑制口臭，保持牙龈健康，设计是相当简单的。五十年代早期以来，发展了治疗用的牙膏，它含有各种不同作用的添加剂，目的是控制牙周病和减少龋齿发病数。简略叙述牙齿以及牙龈的解剖学，对于理解口腔卫生制品的作用是有帮助的。     

火焰原子吸收法测定牙膏中锶

锶是保健牙膏的重要成份之一，含锶的牙膏具有脱敏和镇痛作用，对牙齿酸蚀症、牙齿过敏有良好的效果。能消除牙齿由于冷、热、酸、甜所引起的各种疼痛，经常使用可坚固牙齿，增强牙齿抵抗外界刺激的能力。锶在牙膏中的最高允许浓度为3．5％，但对锶的测定方法一直没有合适的方法作为国标，对含锶牙膏中锶的多少也没有及时检测。本文用原子吸收法对牙膏中锶的测定进行了实验，     

口气清新的秘密

洁白的牙齿,清新的口气,既是健康的标志,又能增添个人的自信！试想如果本已胜券在握的生意只因“口气不佳”而与你失之交臂;或一直令你心仪的女友也为这“恼人之气”而对你“保持距离”,你将作何感想?其实,改变这一状况并不难。9月20日是全国爱牙日,在洁齿、护齿,大讲口腔卫生之时,我们特向大家推介一组使口气清新的实用方法。     

羟基磷灰石与美容牙膏

描述了龋齿产生的原因，通过分析羟基磷灰石的结构特性和作用原理，采用与牙齿有相似结构羟基磷灰石制得的牙膏，进行临床试验证明，羟基磷灰石牙膏具有防龋、杀菌和美白牙齿功能。     

儿童牙膏市场及儿童牙齿的护理

对儿章牙膏的市场现状进行了分析。指出我国有庞大的儿童牙膏消费群体，儿章牙膏市场潜力巨大。对目前我国儿童牙膏市场的主要竞争进行了分析。阐述了儿童牙膏与成人牙膏的区别，对儿童牙病的预防以及儿童牙齿的护理进行了论述。     

过氧化脲牙齿美白剂开发及应用研究进展

过氧化脲可通过持续释放活性氧达到牙齿美白的目的，适用于各种原因引起的着色牙齿的美白。它可同时美白多个牙齿，美白效率高、费用低、使用方便和刺激性小，详细介绍了国内外专利配方及其使用效果；总结了国内外对过氧化脲牙齿美白剂的应用研究和对牙釉质、牙本质的影响；指出了国外研究的发展趋势，结合我国的实际情况对我国开发过氧化脲牙齿美白剂的方向提出了建议。     

In vitro assessment of tooth color changes due to orthodontic treatment using knowledge discovery methods

Esthetic dentistry imposes several demands on the artistic abilities of the dentist, and knowledge of the underlying scientific principles of tooth color is considered to be essential by Sikri. The supervised classification methods, such as the artificial neural networks, the support vector machines, and also the Bayesian classifier, and the feature selection methods, such as decision trees, genetic algorithms and neural networks, as well as independent component analysis combined with least square support vector machines, were applied successfully in the medical field but were less implemented in the dental analysis domain. This study was conducted on extracted premolars from people who required orthodontic treatment. Data gathering was done using spectrophotometric recordings of tooth color parameters before and after accelerated bleaching, staining, and control procedures on extracted teeth on which was simulated orthodontic treatment. Comparison between data mining techniques and classical statistical interpretation of data was done. The results demonstrated the usefulness of these innovating data assessment techniques in the dental field.     

Fracture behaviour of teeth with conventional and mini-invasive access cavity designs

Presented work is targeted toward fracture analysis of endodontically treated human teeth. Three sets of teeth were loaded by compression simulating natural loading conditions. For this purpose, each tooth was mounted into the resin in the axis angle declination of 30° and kept all the time in saline up to the moment of test to simulate the intraoral environment. Two access cavity designs – mini-invasive (conservative) and conventional (traditional), were analysed. Fracture behaviour of treated teeth with mini-invasive access was compared with conventional and with the intact set of teeth. Complex monitoring of the fracture process together with loading traces enables to characterise typical fracture features and crack propagation schemes. The extensive fractographic analysis reveals the effect of adhesive bonding on the crack propagation. Also, fracture initiation and damage accumulation were identified. The quality of newly developed mini-invasive design in comparison with the conventional one was proved.     

带旋流口的椭圆齿平带传热管内自动清洗及其强化传热

针对较低流速下传热管内容易生长污垢和低传热系数问题,本文提出一种具有旋流口椭圆齿的新型平带。在平带的椭圆齿前两侧设计交错排布的旋流口,使传热管内的液体形成类似斜齿螺旋扭带那样的螺旋线液流,从而使旋流口椭圆齿平带同样具有斜齿螺旋扭带能够在较低流速下可靠自转清洗防垢的功能。由于平带上轴向等距离排布的椭圆齿齿后产生大量强烈的涡流,使管内的对流传热得以非常有效的强化,管内侧传热膜系数比空管时提高近一倍,其强化幅度达到光滑扭带的6倍以上。虽然流体阻力远高于光滑扭带,但是设备阻力仍然在一般工程容许的范围内。这种新型结构的旋流口椭圆齿平带可以注塑成型,制造费用低、制品质量好,便于大批量生产和推广应用。     

Comparative clinical wettability of teeth and intraoral mucosa

The observed reduced adhesiveness of human intraoral mucosa, as compared with adjacent teeth, was determined for 14 healthy humans to correlate with differing measured intraoral contact angles for a variety of otherwise non-interacting test liquids on these two equally water-wettable surfaces under clinical conditions. Measurements were made on the front maxillary tooth surfaces and the-inner lower lip mucosal surfaces of the same subjects, either immediately upon first exposure of the oral tissues or after 30-60 s drying in ambient air. Lower critical surface tensions were found for wet mucosal surfaces (25.4 mN/m) than for wet tooth surfaces (31.2 mN/m). Exposure to air for up to 1 min increased the mucosal critical surface tensions by only 2 mN/m, and had even less influence on the measured properties of tooth surfaces. These data suggest that the observed 'bioabhesive' surface quality of oral mucosa, retaining negligible plaque, is associated with its critical surface tension in the zone near 25 mN/m, as found earlier for the natural fouling-resistant surfaces of dolphins and killer whales.     

Effect of methyl methacrylate monomer on bond strength of denture base resin to acrylic teeth

Bond failures at the acrylic teeth and denture base resin interface are still a common clinical problem in prosthodontics. The effect of methyl methacrylate (MMA) monomer on the bond strength of three types of denture base resins (Acron MC, Lucitone 550 and QC-20) to two types of acrylic teeth (Biotone and Trilux) was evaluated. Twenty specimens were produced for each denture base resin/acrylic tooth combination and were randomly divided into control (acrylic teeth received no surface treatment) and experimental groups (MMA was applied to the surface of the acrylic teeth for 180 s) and were submitted to shear tests (1 mm/min). Data (MPa) were analyzed using three-way ANOVA/Student's test (α=0.05). MMA increased the bond strength of Lucitone denture base resins and decreased the bond strength of QC-20. No difference was detected for the bond strength of Acron MC base resin after treatment with MMA.     

Evaluation of different restoration techniques on fracture resistance of teeth with palatinal cusp fracture

We evaluated reattached tooth fragments in terms of fracture resistance in endodontically treated maxillary premolars with one remaining wall. In total, 60 double-rooted, mature, human maxillary premolars with double canals were used. Ten intact teeth were served as a control group without any application. After endodontic treatment, the palatal wall of the teeth was cut parallel to the horizontal axis on the cementoenamel junction using a diamond disc. The teeth were randomly divided into five groups (n = 10) and were restored as follows. Group 1: restored with composite resin; Group 2: palatal wall bonded to the teeth using adhesive resin, then restored with composite resin; Group 3: teeth restored as in Group 2, plus a post space prepared below 2 mm from the palatinal cusp horizontally, then fibre post bonded using adhesive resin cement; Group 4: cavity enlarged to a depth of 2 mm in the cusp of the palatal wall, then restoration performed as in Group 2; and Group 5: fibre post placed in the root canal and then restoration performed as in Group 1. Failure load testing was performed with a universal testing machine. Kruskal–Wallis and Conover’s multiple comparison tests were used to analyse the data. In the restoration groups the highest median load at failure was observed in Group 4, in which cusp capping was used; the lowest was found in Group 3, in which a horizontal fibre post was applied with the reattached tooth fragments.     

Cleaning Teeth Reduces the Inflammatory Response of Macrophages to Acid Dentine Lysate

Particulate autogenous tooth roots are used for alveolar bone augmentation surgery; however, dental plaque may provoke an inflammatory response that may counteract the desired graft consolidation process. Traditional mechanical cleaning of extracted teeth may be of support to lower a possible inflammatory response of the autograft. To test this assumption, extracted porcine teeth were left either uncleaned or underwent mechanical cleaning with a toothbrush and toothpaste before being fragmented and subjected to acid lysis, termed as unclean acid dentine lysate (ucADL) and clean acid dentine lysate (cADL), respectively. The inflammatory responses of murine macrophage RAW 264.7 cells being exposed to the respective acid dentine lysates were evaluated at the level of inflammatory gene expression and IL6 immunoassays. We report here that acid lysates obtained from uncleaned teeth provoked a robust increase in IL1β, IL6, and COX2 in RAW 264.7 cells. The mechanical removal of dental plaque significantly reduced the inflammatory response. Consistently, Limulus tests revealed that tooth cleaning lowers the presence of endotoxins in dentine lysates. To further prove the involvement of endotoxins, a toll-like receptor 4 (TLR4) inhibitor TAK242 was introduced. TAK242 abolished the inflammatory response provoked by acid lysates obtained from uncleaned teeth in RAW 264.7 cells. Moreover, nuclear translocation and phosphorylation of the TLR4 downstream NFκB-p65 were attenuated at the presence of cleaned versus uncleaned dentine lysates. Taken together, our data support the importance of dental plaque removal of teeth being extracted for alveolar bone augmentation surgery.     

同步带在汽车发动机上的应用现状及发展趋势

汽车发动机同步带在日本、欧洲、美国已在多种车型上广泛使用；我国正处于开发试验阶段，但已有一定数量的国产汽车使用。目前汽车发动机同步带的齿型主要为梯形齿，主体橡胶为氯丁橡胶．骨架线绳为玻璃纤维绳，齿包布为尼龙帆布；今后的发展方向是：齿型为圆弧齿，主体橡胶为氢化丁腈橡胶或氯磺化聚乙烯橡胶，骨架材料为芳给１４１４纤维、Ｐ８４纤维和ＰＢＩ（聚苯并咪唑）纤维，齿包布为耐磨且抗剪切的新型织物。