牙齿的

When treatment is finished the teeth need to be held in position for a time. This period is called retention, and the appliances that hold the teeth in place are called retainers.

当治疗完成的牙齿需要加以举行的立场，今后一个时期，这个时期是所谓的保留，以及家电举行的牙齿在的地方，是所谓的聘约。

Three years of tram tracks , elastic bands and the removal of eight teeth later , and I am a shining example of the orthodontist's art but every time one of my children loses a milk tooth , I know it could cost far more than www.6cc.cn

经过三年的纠正，绑带以及后来拔掉的8个牙齿，我成为畸牙矫正医生的一件闪光的杰作；但是每次我的小孩掉了一颗奶牙，我知道它绝对不止牙齿童话故事里的1英镑。

Then, in 1979, a well-designed study by pediatrician and psychiatrist Herbert Needleman resolved the dispute by establishing a direct correlation between the lead content of a child's teeth and bad classroom behavior. Twelve years later follow-up studies on these children found that those who had the highest lead levels in their teeth as children continued to have school problems through their last year of high school including more school failures, reading disabilities, and lower class standing.

到1979 年，由儿科医生兼精神病学家赫伯特·内德勒曼设计的一个著名实验证明不良的学习成绩与儿童牙齿中的铅含量直接相关，从而为争议下了定论12 年后对这些人的后续研究表明，当年牙齿中含铅量最高的孩子在中学毕业前一直存在学习上的问题，包括考试不合格、阅读障碍和班级排名靠后。

In 1667 a Danish naturalist, Nicolaus Steno, recognized these findings as ancient shark teeth. In 1835 a Swiss naturalist, Louis Agassiz, gave this mysterious creature the name by which it is known today, Megalodon — which in Greek means 'big tooth'.

在1667年，一位丹麦的自然学家Nicolaus Steno鉴定这些发现为古代鲨鱼的牙齿。1835年，一位瑞士的自然学家Louis Agassiz，给予这个神秘的生物一个我们现在总所周知的名字：Megalodon，这个词在希腊语中意思是"大牙齿"。

There is no doubt that bacteria are the main etiologic agents for periodontal disease. With the progression of periodontal destruction, the following syptoms may occur: moderate to severe gingival inflammation, increased tooth mobility, pathological migration, vertical occlusal dimension loss, improper crown to root ratio, furcation involvement, absence of keratinized gingiva, unaesthetic appearance, as well as difficulties in chewing causing by unstable occlusion.

中文摘要细菌是牙周疾病的主要致病因素已是不争的事实，但随著牙周疾病破坏的进程，临床上表现出来的徵兆除了中度至重度不等的牙龈发炎现象之外，更可发现牙齿摇动度渐增、牙齿位移、咬合高度丧失、不良的牙冠根比、根叉病变、角化牙龈宽度不足、美观不佳、更甚者缺乏稳定的咬合导致咀嚼困难等。

There is a slight prominence of the nasal bone structure causing a slightly Roman appearance, the center line running up over the foreface with little or no stop, falling away in front of the eyes so there is an absolutely clear outlook with no interference; the underjaw showing great strength, the jaws long and punishing; the mouth level, meaning that the teeth from the upper jaw and lower jaw match evenly, neither overshot nor undershot. This is a difficult mouth to breed.

鼻骨轻微突出的结构使它似乎具有罗马人特征，中心线沿着前颜面逐渐加宽，在眼部前方消失，所以无需推知，就可以完全精楚的知道它的外观；它的下颌显得十分有力，口部长而有力，嘴比较平，也就是说上颚的牙齿和下颌的牙齿匹配适当，上颚不突出，下颌也不突出。

In 1667 a Danish naturalist, Nicolaus Steno, recognized these findings as ancient shark teeth. In 1835 a Swiss naturalist, Louis Agassiz, gave this mysterious creature the name by which it is known today, Megalodon — which in Greek means 'big tooth'.

在1667年，一位丹麦的自然学家Nicolaus Steno鉴定这些发现为古代鲨鱼的牙齿。1835年，一位瑞士的自然学家Louis Agassiz，给予这个神秘的生物一个我们现在总所周知的名字：Megalodon，这个词在希腊语中意思是&大牙齿&。

Notch1 is expressed by stem cells resided in the cervical loop epithelium, and Notch signaling pathway play a central role in fate decision of those stem cells. Notch receptors and their ligands are involved in both patterning and cell fate determination during odontogenesis. Moreover, many cell factors, which are closely related with odontogenesis, could regulate expression of Notch receptors or their ligands.

既往研究显示：早在牙齿发育期，Notch1就表达于颈环星网状层的干细胞中，是其保持干细胞性质的重要机制；Notch-Delta信号还与成釉细胞、成牙本质细胞分化有关，被认为是牙齿发育细胞分化多样性的原因之一；另外，目前已明确与牙胚细胞分化有关的生长因子如TGFβ、FGF、BMPs等均可诱导Notch受、配体的表达。

The potential of the dental crown to the middle point of dental root gradually reduced when the pH value of artificial saliva decreased.So adsorption of the cariogenic bacterium on the dental surface increased,incidence of the caries also possibly increasd.

本研究在人工唾液不同pH值时，通过对牙齿表面电位的测定，来观察牙齿表面电位随着人工唾液pH的变化，情况并探讨二者之间的关系，从而揭示酸的致龋机理，为龋病发病机理的研究提供一些实验数据。

What usually happens to these two pieces is that the pinion, which has a small cone-shaped end with teeth that fit on the ring, shaves off the ring's teeth and is thus unable to deliver traction to the wheel.

什么通常发生在这两个部分是，小齿轮，它有一个小的圆锥形的牙齿，环形适合，徒弟们把环的牙齿，因此无法提供的牵引力的车轮状结束。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。