Oral Microorganism
Abstract
Oral microorganisms are the organisms that are found in the buccal cavity. They are classified based on the various features they possess, and this includes morphology, colonial appearance, fermentation products, among others. Microflora existences in the buccal cavity have a symbiotic relationship with the host. They colonize the buccal cavity through the opening, which is the entry to the body. The environment must be conducive for microbiota to survive. Their survival influenced by the state of the host either in healthy or disease states. The plaque biofilm is formed through five steps that include association, adhesion, proliferation, microcolonies formation, biofilm and plaque growth, and maturation. Calculus refers to the dental plaques that have been calcified. Factors that affect the growth of oral microorganisms include temperature, redox potential, the saliva PH, nutrients, host defenses, genetics, and lifestyles. The formation of biofilms then dental plaques and the constant addition of the plaque and having an acidic environment leads to the formation of dental caries. Gingivitis refers to the inflammation of the gingiva due to invasion by bacteria, which the immune system tries to fight, and in the process, inflammation ensues.
Oral Microorganism
The body has various organ systems and, as such, has a different organism that resides in such a unique niche. In the same way, the mouth is a unique part of the digestive system that acts as the gateway into the body. It has its unique environment that favors various microorganisms while at the same time being hostile to others. Such microorganisms have adapted to the physiology of the oral cavity hence playing a crucial role in the digestive function of the mouth with its various components. The mouth has the digestive enabling environment for the food that is taken by the humans, and this includes the environment and the digestive enzymes that are contained in the saliva which is the fluid that is secreted by the various salivary glands found around the mouth for the purpose (Marsh et al., 2016). The host, which is the human being and the resident microorganisms, has a symbiotic relationship where each has a benefit for coexistence. This delicate balance has to be maintained; otherwise, it becomes dysbiotic, leading to one of the parties benefitting negatively, and this especially to the host. In addition to aiding digestion, and oral microorganism help in preventing access and colonization of the mouth by the exogenous microbiota, synthesis of crucial compounds like vitamins, for example, vitamin B, and also promotes an individual’s immune system. This essay provides an analysis of oral microbiota classification, oral microflora in health and disease, acquisition of oral microflora, plaque biofilm formation, calculus formation, factors that affect the growth of microorganisms in the oral cavity and etiology of dental caries and gingivitis.
Oral Microbiota Classification
The oral cavity has many different microorganisms that can be found hence the need to know how they are classified for a better understanding of the organisms. It is through understanding the various groups of the microorganism that one can recognize their characteristics and differences. Taxonomy is the name given to the process of classifying organisms based on their similarities and differences in their features. The characteristics that are used in the classification include cellular morphology, colonial appearance, and carbohydrate fermentation, and amino acid hydrolysis, the pattern of fermentation products, preformed enzymes, antigens, lipids, DNA, enzyme profile and peptidoglycan (Marsh et al., 2016). For example, on the part of cellular morphology, the organisms can have gram stain reaction, those with flagella and spore-producing, or also the size difference. The colonial appearance grouping and classification can be based on color, shape, size, and whether they cause hemolysis or not. Classification based on amino acid hydrolysis is whether the microorganism produces ammonia or not. The enzyme profile is based on either presence or absence of electrophoretic mobility. An organism can have more than one characteristic making it to have some features similar to another. For example, there are gram-positive microorganisms that have the same shape as being rod-shaped, while others are maybe gram-positive but are cocci in shape. Some of the organisms found in the oral cavity include streptococcus, Enterococcus, Corynebacterium, campylobacter spp, lactobacillus, among others.
Oral Microflora in Health and Disease
Oral microflora coexists with the host in a symbiotic relationship where both the host and the organisms stand to benefit. In other words, they help one another to survive. When an individual is healthy, the environment for the existence of the microorganisms is enhanced; hence they can multiply and, at the same time, help the individual in the many ways such as in the digestion of food at the buccal cavity. The environment, for example, the Ph is usually conducive for the endogenous organism to extract their nutrients while at the same time benefitting the host, which is the human being (Marsh et al., 2016). There are times when the person may be ill, and hence this affects even the oral microflora existence and their functions. For example, a person who has human immunodeficiency syndrome (HIV) has their immunity working at the minimum. This will also affect the microflora existence and ability to prevent exogenous microbiota from invading the oral cavity. In the disease state, the oral microflora number is reduced. Hence, they do not offer the competition against the invasion by other microorganisms, especially the opportunist infection-causing organism like Candida Albicans that causes candidiasis.
When the person is in a disease state, the oral microflora will not be able to prevent the exogenous microorganisms from attacking the host adequately. The adhesion receptors will be idle and ready to be attached by the pathogen, which is typically occupied in a healthy state individual. Besides, there will be competition for the endogenous nutrients that are provided by the host system. In this way, the exogenous organisms thrive better and multiply further to weaken both the host and the endogenous microorganisms. In healthy individuals, the endogenous microflora typically creates an environment that is hostile for the exogenous to survive even if they can be attached and invade the oral cavity. When the host is in the disease state, they are not able to provide that conducive environment help work at a minimum, and this makes them not provide the much-needed protection by provision pf a hostile environment for the pathogens to multiply and further cause disease. In a healthy individual, the oral microflora can produce substances that are inhibitory to the existence of the exogenous pathogens. Such elements include hydrogen peroxide, bacteriocins, and bacteriophage, among others (Marsh et al., 2016). Also, the endogenous microbiota boosts the immune system by initiation and promotion in the production of antibodies that further help the body fight against pathogens that invade the oral cavity. All these factors provide colonization resistance by the oral cavity for the healthy individual, and this is compromised in case the individual is in a disease state, moreso a condition that compromises the immune system.
Acquisition of Oral Microflora
The oral cavity being the gateway into the human being, has many characteristics that make it hostile or friendly in microflora colonization and existence. The ecological environment of the buccal cavity dictates whether an invading microflora will survive or not. All this is dependent on what the individual is taking as food, the saliva, and the overall hygiene of the individual. The surfaces that provide for the colonization of the buccal cavity include the mucosal surfaces of the lips, cheek, palate, and the tongue and the teeth. Later in life, one may have the orthodontic appliances. Early in life, it is only the mucosal surfaces that provide an environment for oral microflora to flourish. The tongue is an excellent breeding and colonization environment for the anaerobic oral microflora; hence they are generally found in such ecology (Marsh et al., 2016). The presence of teeth that have different parts provides unique niches for the various oral microflora to invade and multiply hence get acquired. For example, the gingivae crevice and fissures have a conducive environment where microflora with fermentation properties thrive very well. Acquisition of microflora, therefore, depends on the buccal cavity environment and also the age of the individual since it influences the content and also what one takes as food, which to a larger extent dictates the type of environment.
Plaque Biofilm Formation
Dental plaque is a microbial community that develops on the surface of a tooth to be called the biofilm. The plaque is embedded and enclosed in a matrix of polymers whose composition is both the bacteria and the saliva. Plaque is found naturally on the tooth surface and forms part of the host defense system in fighting colonization by exogenous microbiota (Marsh et al., 2016). The problem comes in when the plaque becomes too much in accumulation to the point of predisposing such sites to diseases. The process of dental biofilm formation undergoes five steps which are: association, adhesion, proliferation, microcolonies formation, biofilm and plaque growth, and maturation. The first step usually is the association. The association is through physical forces associated with bacteria and the pellicle. The next step is adhesion, which is done through their use of adhesins binding the bacteria to the pellicles. The primary colonizers provide a surface for the subsequent bacteria to also join and form the biofilm. The third step involves the growth of the bacteria, which is rapid proliferation as long as the conditions remain favorable. The fourth step is now the formation of the microcolonies. Bacteria like streptococcus provides polysaccharides that have extracellular protective properties. The final stage involves the microcolonies forming complex groups that make up the biofilm, which means the attached plaque. Beyond the biofilm are the plaque growth and subsequent maturation.
Calculus Formation
Calculus refers to the dental plaques that have been calcified. Calcification is achieved through the mineralization process that involves the deposition of minerals in the already formed dental plaques. The minerals that form the calcification include apatite, whitlockite, brushite (Marsh et al., 2016). Besides, proteins and carbohydrates also form the calcification process to achieve calculus. The mineralization is both intracellular and extracellular. Calculus occurs both supragingival and subgingivally. At this location, they add to the biofilm formation, and this can be the root cause of gingivitis for many individuals. Porous calculus causes retention of bacteria antigens leading to a cascade of bone resorption by periodontal bacteria. The formation of calculus risk increases with individual age.
Factors That Affect the Growth of Microorganisms in the Oral Cavity
For the microorganisms to survive and grow in the oral cavity, there are a serious of factors that determine such survival. These factors include temperature, redox potential, the saliva PH, nutrients, host defenses, genetics, and lifestyles. Temperature determines the extent to which organisms can operate and maximize physiology for their body. The constant temperatures of 35-36 degrees centigrade provide a stable environment for gene expression and multiplication of the microflora; hence the organisms can survive. According to Marsh et al. (2016), despite the access of the buccal cavity by air, very few microflorae require oxygen to carry out their functions and survive optimally. Most of the buccal microflora are anaerobic and need little or no oxygen for them to survive and multiply in the environment. The obligately anaerobic microorganism would not require oxygen to survive actively, and in the presence of such conditions, it becomes toxic and can even destroy the microbiota. Aerobic microorganisms in the buccal cavity would operate and have maximum metabolism since they can get the much-needed oxygen. However, for the strict anaerobic lot, oxygen presence is the only limiting factor for their survival and metabolism. This means that it is the redox potential at any particular environment within the buccal cavity that would influence the survival of such microorganisms.
The PH of unstimulated saliva is between 6.75 and 7.25 and is therefore near neutrality (Marsh et al., 2016). Most of the microorganisms survive and work better in PH near neutrality; hence the buccal cavity provides such a conducive environment for their metabolism. The highest PH is found at the palate while the lowest is at the buccal cavity. Such will, therefore, determine the distribution of the bacteria in the buccal cavity.
The oral microflora depends solely on the host to provide nutrients for their metabolic demands. These can either be exogenous or endogenous nutrients. The main source of endogenous nutrients is saliva. This contains amino acids, proteins, glycoproteins, and vitamins for the consumption of the microflora. The GCF found in the gingival crevice also provides nutrients like albumin and heme-containing molecules for the microorganism to consume. The oral microorganism that cannot break the nutrients depends on their counterparts who are able to do so and become available for consumption. Others may have to provide various components of enzymatic steps in the breakdown process hence synergistically helping one another to obtain the much-needed nutrients (Marsh et al., 2016). The exogenous nutrients are found in the foods that the host eats. The fermentable carbohydrates are the main component of the exogenous nutrients that provides food for the bacteria since they can easily be broken down in the mouth. Nitrate in the vegetables also influences the dietary needs of the microflora in the oral cavity since they can be reduced to nitrites by the oral facultative anaerobes in the mouth.
The host defenses also influence the activity of oral microflora by providing protection. The integrity of the buccal mucosa and enamel are the physical protection barriers for the bacteria in the mouth. Besides, immunity, which includes innate and adaptive, ensures that pathogens do not replace the endogenous microflora in the surfaces; hence they can survive and multiply. Desquamation, for example, ensures that the right amount of microorganisms is achieved so that it can balance available resources and the requirements for survival (Marsh et al., 2016). Mucins also help in destroying invading microorganisms by agglutination. Epithelial lymphocytes protect exogenous a microorganism which ensures the survival of the microorganisms in the buccal cavity.
The genetics of the host influences the presence and survival of some microorganisms. For example, periodontal disease was found to be common in a certain gender, and genetic makeup hence influences the microbiota that causes such a condition. The lifestyle of an individual is basically what such people consume as diet. Those who take a lot of sugars are susceptible to microbiota that survives in low PH. Biofilms form such individuals will be made of bacteria that survive in an acidic environment hence survive better than those that require alkaline.
Etiology of Dental Caries and Gingivitis
Etiology refers to the cause of something and, in this case, the cause of dental caries and gingivitis. Dental caries refers to the cavities found on the surface of teeth due to a combination of factors that include bacteria invasion, acidic media, and dental plaques (Marsh et al., 2016). The formation of biofilms then dental plaques and the constant addition of the plaque and having an acidic environment leads to the formation of dental caries. Gingivitis refers to the inflammation of the gingiva due to invasion by bacteria, which the immune system tries to fight, and in the process, inflammation ensues. Gingivitis follows the formation and accumulation of dental plaques that remain on the teeth without being removed and cleaned. Their presence leads to their invasion of the gingiva, and the host immune system responds to the antigens formed by the bacteria in dental plaques by mounting an immune response hence inflammation of the gingiva.
References
Marsh, P. D., Lewis, M. A., Rogers, H., Williams, D., & Wilson, M. (2016). Marsh and Martin’s Oral Microbiology-E-Book. Churchill Livingstone.