Study On Plaque Ultrastructure By TEM And GbpB Of Streptococcus Mutans By Immunoelectron Microscope

Dental caries is a disease that depends on many factors, the most important of which is the plaque. The plaque has many microorganisms, and these microorganisms have much relation with the caries development. It is important for us to know the structure and formation of the plaque for the treatment and prevention of caries.Mutans streptococci (MS) are the primary cariogenic agents, and Streptococcus mutans (S.mutans) is believed to have the closest relationship with human caries. It includes three serotypes: c, e, and f. Its abilities to adhere to tooth surfaces and aggregating with each other help to form the dental plaqueand initiate the process of tooth decaying. There are many factors influencing adherence and aggregation. Recently, a kind of surface proteinæ¡®lucan-binding proteins(Gbps), were paid more and more attention because they act as "bridge" between bacteria and matrix of dental plaque. In this study, we established a dental plaque model to observe the structure and formation of plaque and want to study the role of GbpB in plaque formation by immunoelectron microscope.The study consist of three parts:1. TEM study of the plaque ultrastructure m v/voThe specimens of Iday, 5 days and 9 days were serially sectioned. The sections were imaged by TEM. Those specimens were also observed by microscope after they were stained by Gram's and Methylene blue. The TEM results showed that there were few microorganisms in early plaques, mainly of which were coccus. With the time went on the kind and quantity of the microorganisms became more, also bacilli and campilobacter appeared. There were bacilli in both sides and the fence-like structure of coccus in mature plaques, in which some bacteria went to necrosis. The plaque include many bacteria, such as coccus,bacilli,campilobacter and so on. The distributed state of bacteria in the plaques observed by Methylene blue stain was similar to that of TEM. The results of plaques stained Gram's showed that positive bacteria were distributed coccus and negative ones were plexiformly distributed campilobacter .2. Immunoelectron microscope study of the GbpB in plaqueThe sections were stained by colloidal method. The results showed that the granules are mono-layer and bad-distributed, mainly on the surface of the Streptococcus mutans. Intensive granules in blocks of Streptococcus mutans-5-shows that GbpB may be important in the gathering of Streptococcus mutans.3. CLSM study of the plaque structureThe specimens were imaged by CLSM with the flurorescein staining and thethree-dimension structure was rebuilded by computer. The results showed that the plaque is a complex structure with heterogeneous distribution of cells matrixes and voids.