口腔生物学精品教学（中山大学）【口生】Review of the oral biology.docVIP

Review of《THE ORAL BIOLOGY》 1st Version ATTENTION: All the contents in this review are reference to the SLIDE from the teachers in the Guanghua Stomotology School in SYSU and the ORAL BIOLOGY (the 4th version ) , which are summarize by Le. All rights reserved. Le 19/11/2012 CHAPTER 1 Oral Microbiology SECTION 1 The Oral Ecosystem and the Affecting Factors ONE——The Ecosystem and the Ecology ■Ecological Succession TWO——The Oral Ecosystem ■Oral Ecosystem ·Ecology is the science that studies interrelationships between organisms and their living (biotic) and nonliving (abiotic) environment. An ecosystem consists of the microbial community living in a defined habitat and the abiotic surroundings composed of physical and chemical elements. ?In its simplest expression, the oral ecosystem is thus composed of the oral microorganisms and their surroundings, the oral cavity. ■Habitats （栖息地） ·The oral cavity is a moist environment which is kept at a relatively constant temperature (34 to 36°C) and a pH close to neutrality in most areas and thus supports the growth of a wide variety of microorganisms. However, the mouth must not be considered a uniform environment as the oral cavity possesses both hard (teeth) and soft (mucosa) tissues. Hard surfaces ?The tooth can be described as a nonshedding hard surface that offers many different sites for colonization by bacteria below (subgingival) and above (supragingival) the gingival margin. Soft surfaces ?The oral mucosa is characterized by a continuous desquamation of its surface epithelial cells, which allows rapid elimination of adhering bacteria. The mucosa that covers the cheek, tongue, gingiva, palate, and floor of the mouth varies according to the anatomical site. Water bath ·The oral surfaces are also constantly bathed by two important physiological fluids, the saliva (唾液) and the gingival crevicular fluid （龈沟液）. These fluids are essential for the maintenance of the oral ecosystems by providing water, nutrients, adh