Tooth decay Streptococcus mutans

The most common oral condition and dental emergency is dental caries, which is a destructive disease of the hard tissues of the teeth due to bacterial infection with Streptococcus mutans and other bacteria. It is characterized by destruction of enamel and dentine. Dental decay presents as opaque white areas of enamel with grey undertones and in more advanced cases, brownish discoloured cavitations. Dental caries is initially asymptomatic and pain does not occur until the decay impinges on the pulp, and an inflammation develops. Treatment of caries involves removal of the softened and infected hard tissues, sealing of exposed dentines and restoration of the lost tooth structure with porcelain, silver, amalgam, composite plastic, gold etc. 

A freshly cleaned tooth surface quickly becomes coated with a thin pellicle of salivary proteins. This provides a surface for growth of dental plaque, which contains many bacteria and adhesive polysaccharides such as dextrans.1 The latter are generated from dietary sucrose by such bacteria as Streptococcus mutans. (Chapter 20) and others.131 Many factors affect the probability of tooth decay. 

This chapter describes dental caries (tooth decay) and its causes. Sucrose and other mono- and disaccharides are metabolized to acid (lactate) by bacteria that remain in stagnation areas of the teeth. Rats and hamsters fed a 50% sucrose diet developed a caries-sensitive, predominantly gram-positive microbiota that became caries resistant when the rodents were fed penicillin (Sect. 1). Further studies identified Streptococcus mutans (S. mutans) as the etiological agent. This organism synthesizes an insoluble polysaccharide capsule that is stable and retains lactate at the enamel surface (Sect. 2). The key enzyme, glucosyl transferase, is related to salivary amylase which adheres to oral bacteria and enhances bacterial acid production. The chapter concludes with a discussion of salivary and other factors responsible for the marked variation observed in individual caries experience (Sect. 3). 

H ow many times have you heard the lecture from parents or your dentist about brushing your teeth after a sugary snack Annoying as this lecture might be, it is based on sound scientific data that demonstrate that the cause of tooth decay is plaque and acid formed by the bacterium Streptococcus mutans using sucrose as its substrate. 

Action of the glucosyl transferase of Streptococcus mutans, which is responsible for tooth decay. 

Tooth decay (dental caries) is one of the most common diseases in humans [8]. It has been defined as a chronic, dietomiaobial, site-specific disease caused by a shift from protective factors favouring tooth remineralization to destructive factors leading to demineralization [9]. The specific factors leading to destruction of the mineral phase of the tooth are the presence of oral bacteria, mainly Streptococcus mutans [10], and the availability of fermentable carbohydrates from the diet. This combination leads to the production of organic acids as a result of the metabolic process of the bacteria, of which the main one is lactic acid, though other weak acids, such as ethanoic and propanoic can also occur [11]. These acids dissolve the mineral component of the tooth, leading to loss of structure. 

One of the most important problems of cell adhesion is dental plaque, which is formed when bacteria such as streptococcus mutans and streptococcus sanguis adhere to tooth surfaces, causing decay (caries) and gum disease (gingivitis). Dental plaque can be removed by brushing or prevented by chemical additives, such as chlorhexidine, which kill the bacteria. Study of dental plaque is normally done on hydroxy apatite which is the main component of dental enamel. 

Surface Polysaccharides in Cariogenicity. The production of dental caries (tooth decay) is strongly associated with the presence of Streptococcus mutans. Other oral streptococci, e.g. S. sanguis and 5. salivarius, and lactobacilli are also found in the lesions, but are not considered to be primary pathogens, except in caries initiated in dental fissures and pits where food has become impacted and strong adhesive properties are not essential. 

Methanohc extract markedly inhibited water-insoluble glucan synthesis (an initial step in tooth decay) by the cariogenic bacterium Streptococcus mutans the active principles were found to be oleanolic acid (see also Ugustrum) and ursohc acid. Common jujube has no significant toxic effects on experimental animals. ... 

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