Firstly, the developing principles of the cylindrical internal helical gear are proposed through analyzing the movement and geometry requirements, which provides continuous contact between the mating gear surfaces. The tooth surface of the internal helical gear in the new gearing can be imagined as being generated by the normal section of the conjugated surface of the ball-tooth, moving along the radial projection of helix line of the tooth-root circle. Also, the proposed surface can be approximate tangent to the conjugated surface of the ball-tooth along a spacial curve.

首先欧美性恔图片在线观看，通過分析保證行星輪作螺環(huán)運(yùn)動時與內(nèi)斜齒輪實現(xiàn)連續(xù)嚙合傳動的運(yùn)動和幾何條件五月在线视频，提出了圓柱內(nèi)斜齒輪齒面的兩種形成原理：即由球齒運(yùn)動包絡(luò)曲面的法截面沿其齒根圓螺旋線在徑向的投影進(jìn)行拓展所形成的內(nèi)齒面一级二级黄色视，以及與球齒運(yùn)動包絡(luò)曲面呈近似相切接觸的等螺距齒面構(gòu)成的內(nèi)齒面激情自拍三级文学视频激情。

The gum atrophies to still cause the tooth dew outside the root, the surface of tooth root doesn't have tooth enamel quality, not only be easily worn away while brushing teeth once there being no the protection of guming, in the meantime to cold, hot and sour incitement very sensitive, the mouth cavity medical science is called "tooth essence allergy", people often mistaken for this kind of phenomenon to peep out tooth nerve to cause ache, and this is incorrect.

牙齦萎縮還導(dǎo)致牙根外露性欧美一区二区，牙根的表面沒有牙釉質(zhì)性小说视频，一旦沒有了牙齦的保護(hù)在线看黄免费不卡，不僅容易在刷牙時受到磨損，同時對冷日韩a级毛片AV一区免费在线观看、熱人人摸人人操人人爰、酸的刺激非常敏感，口腔醫(yī)學(xué)稱為&牙本質(zhì)過敏&十大免费黄的色网站，人們常把這種現(xiàn)象誤認(rèn)為是露出牙神經(jīng)導(dǎo)致疼痛精品三级国产三级国产，這是不對的。

The tooth root development is an important part of tooth development. Hertwig's epithelial root sheath takes part in and plays important role in tooth root development.

牙根發(fā)育是牙齒發(fā)育的重要部分无遮挡一级A片高清视频在线观看，Hertwig上皮根鞘(Hertwig's epithelial root sheath人人色人人干人人弄， HERS)參與牙根發(fā)育，并起重要作用国产人成。

root cur：表示 "關(guān)心

379 root cult 表示 "耕種,培養(yǎng)" till | 380 root cur 表示 "關(guān)心" care | 383 root dent 表示 "牙齒" tooth

root dent：表示 "牙齒

380 root cur 表示 "關(guān)心" care | 383 root dent 表示 "牙齒" tooth | 384 root derm, dermat 表示 "皮膚" skin

root canal, pulp canal：牙根管

牙根||root of tooth | 牙根管||root canal, pulp canal | 牙根尖||apex of root of tooth