学号：201209072108 班级：口腔二班姓名：陆小凯
Oral cavity Dentists use special terms to describe the surfaces of teeth. The labial surface(labi/o means “lip”), for incisor and canine teeth, is nearest the lips. The buccal surface(bucc/o means cheek), for premolar and molar teeth, lies adjacent to cheek, as illustrated in Figure 5-2. Dentists refer to both the labial and the buccal surfaces as the facial surface(faci/o means face). Opposite to the facial surface, all teeth have a lingual surface(lingu/o means tongue). The mesial surface of a tooth lies nearest to the median line and the distal surface, farthest from the medialline. Premolars and molars have an additional occlusal surface that comes in contact with a corresponding tooth in the oppsing arch. The incisors and canines have a sharp incisal edge.
Figure 5-3 shows the inner anatomy of a tooth. label it as you read the following description: A tooth consists of a crown, which shows above the gumline, and a root, which lies within the bony tooth socket. The outermost protective layer of the crown, the enamel, protects the tooth. Enamel is a dense, hard, white substance-the hardest substance in the body. Dentin, the main substance of the tooth, lies beneath the enamel and extends throughout the crown. Yellow in color, dentin is composed of bony tissue that is softer than enamel. The cementum covers, protects, and supports the dentin in the root. A periodontal membrane surrounds the cementum and holds the tooth in place in the tooth socket. The pulp lies underneath the dentin. This soft and delicate tissue fills the center of the tooth. Blood vessels, nerve endings, connective tissue, and lymphatic vessels are within the pulp canal. Root canal therapy is often necessary when disease or abscess occurs in the pulp canal. A dentist opens the tooth fromabove and cleans the canal of infection, nerves, and blood vessels. The canal is then disinfected and filled with material to prevent the entrance of microorganisms and decay. Three pairs of salivary glands surround the oral cavity. These exocrine glands produce saliva that contains important digestive enzymes. Saaliva is released from the parotid gland, submandibular gland, and sublingual gland on each side of the mouth. Narrow ducts carry saliva into the oral cavity.
口腔牙医使用特殊的术语来描述牙齿表面。
唇面（labi的意思是嘴唇）是指前牙最接近嘴唇的一面。
颊面（bucc/ O是指面颊）对于前磨牙和磨牙是位于毗陵的面颊，如图5 - 2所示。
牙医把唇和颊面称为面部表面(faci / o意思是脸)。
牙医把唇和颊面称为面部表面(faci / o意味着脸)。
和面部表面相反一面,所有的牙齿都有舌表面(lingu / o意味着舌头)。
牙齿的近中面位于最靠近中线和远侧面，离medialline最远。
前磨牙和磨牙咬合额外的表面与反向拱相应的颌面接触。
切牙和尖牙有锋利的切缘。
图5 - 3显示了牙齿的内部解剖。
下面是你要阅读的标签描述:牙齿是由牙龈表面的牙冠和埋在牙槽骨中的牙根组成。
最外层是保护牙冠
表面的牙釉质。
牙釉质是白色的人体中最坚硬的物质。
牙本质构成牙齿的主体，位于牙釉质的下方充满整个牙冠。
牙本质属于骨组织硬度没有牙釉质大颜色为黄色。
牙骨质具有覆盖、保护和支持牙根的作用。
牙周膜包围着牙骨质和保持牙根在牙槽窝内。
牙髓位于牙本质的下方，柔软且微妙的组织充满了整个牙体中心。
牙髓中包含了血管、神经末梢、结缔组织和淋巴管。
疾病和脓肿发生时，根管治疗往往是很有必要的。
牙医从牙齿的表面打开牙齿，清理牙髓感染的血管和神经。
然后在已经清理的牙髓腔中消毒填充好物质防止微生物进入引起腐烂。
口腔的周围有三对唾液腺。
这些外分泌腺体产生唾液，唾液中包含重要的消化酶。
唾液从腮腺，颌下腺，并在口的每一侧舌下腺释放。
唾液从狭窄的管道进入口腔。