Dental Plaque PowerPoint Presentation

Dental Plaque Asst. Prof. Dr. Özgü İlkcan KARADAĞLIOĞLU  Dental caries Dental caries is a common chronic infectious resulting from tooth- adherent cariogenic bacteria, primarily Streptococcus Mutans, which metabolize sugars to produce acid, demineralizing the tooth structure over time...

Dental Plaque Asst. Prof. Dr. Özgü İlkcan KARADAĞLIOĞLU  Dental caries Dental caries is a common chronic infectious resulting from tooth- adherent cariogenic bacteria, primarily Streptococcus Mutans, which metabolize sugars to produce acid, demineralizing the tooth structure over time. Dental caries is considered a dietary-microbial disease that requires a cariogenic biofilm and regular exposure to fermentable carbohydrates (glucose, fructose, maltose, and sucrose) from the diet. SUGAR HOST CARIES MICROFLORA TIME BIOFILM Biofilm" is a term used to describe areas where microorganisms settle and reproduce on various surfaces, and it can also be found on surfaces such as water pipes, etc. In fact, it plays a very important role in the formation of hospital infections. One of the most important factors that enable microorganisms in the oral flora to remain in this region is their ability to adhere to the tooth surface although free microorganisms can be removed with saliva, streptococci, etc. Some microorganisms are specialized to adhere directly to  A fully developed biofilm is defined as a heterogeneous arrangement of microbial cells on a hard surface. The basic structural unit is formed by microcolonies or cell clusters of bacterial cells attached to the surface. While 15% of the basic composition consists of cells; 85% contains proteins, polysaccharides, nucleic acids and salts. When the biofilm becomes mature; Its structure and composition are modified according to environmental conditions such as growth conditions, inherent properties of fluid movements, physicochemical properties of substrates, and nutrition.  Oral biofilm In the human oral cavity; There are hundreds of different types of microorganisms, including bacteria, viruses and fungi. They live in complex communities organized into a thin layer—biofilm—that covers oral surfaces, much like dental plaque on the surface of teeth. Immediately after cleaning, proteins from saliva cover the tooth surfaces with a film. Bacterial retention to this film layer occurs with the help of microfilaments in the cell walls. When the number of bacteria increases, they will be able to communicate and create a community with the signal molecules they secrete. Bacteria; In addition to the protein and nutritional contents coming from saliva; secretes proteins, polysaccharides, nucleic acids and other extracellular matrix components. This matrix is ​the glue of the biofilm. Microorganisms within the matrix behave differently than bacteria floating freely in saliva. The biofilm community behaves as a unit with a single bacterial response to environmental changes.  Electron microscope studies show a thin layer of cells without bacteria between the surface of the enamel and bacteria. This thin cell-free plate is called Dental pellicle  Dental pellicle is a protein film that forms on the surface enamel by selective binding of glycoproteins from saliva that prevents continuous deposition of salivary calcium phosphate. It forms in seconds after a tooth is cleaned or after chewing. It protects the tooth from the acids produced by oral microorganisms after consuming carbohydrates  The physical and chemical properties of the surface are also very important for the adsorption of this organic film layer. Hydroxyapatite surface is amphoteric. This means that the acidic and basic structures can be together at the same time. In other words, the surface can act base against to acids or can act as acid against the bases. Acidic proteins are related with phosphates while are basics are related with Ca ions. Due to the phosphate structure, the hydroxyapatite surface is a negatively charged (charged) surface.  Hydration layer: If Any charged solid surface touched to a liquid ; immediately attracts opposite- charged particles. Therefore, when the tooth contacts with the saliva, a hydration layer takes called the Stern layer.  The pH of this layer is dependent on its ionic content. This plate contains 90% Ca and 10% phosphate. The sedimentation priority (affinity) of saliva compounds to the enamel surface  High: Acidic chain compounds (phosphorus and sulphated compounds Simple molecules (arginine lysine and carbohydrates)  Moderate: Polar side chains (histidine, serine, threonine, tyrosine)  Less: Aromatic groups, peptidic groups  Functions:  Protecting, improving and repairing enamel surface  Effective in the binding of oral microorganisms.  It is served as the main structure and food source for microorganisms that are adherent  It acts as a reservoir for protective ions and especially fluorides.  Supporting selective permeability to enamel  As asummary  Pellicle is defined as the acellular layer of adsorbed salivary proteins and other macromolecules on the dental enamel surface approximately 10 micrometers thick.  The main role of the pellicle is protective in nature. The pellicle protects the enamel against abrasion and attrition, and serves as a diffusion barrier. As the liquid layer in the pellicle is relatively undisturbed, molecule movement due to non- diffusion forces are lower than in most parts of the salivary film, influencing the solubility behavior of the enamel surface. Dental Plaque Its the deposit of bactaries and bacterial products localizated on uncleaned teeth or accumulation on the restorations in the mouth. Bacteria adhesion to the teeth:  The most important part of bacterial adhesion to the teeth may be because of their hydrophobic structures. Studies shows that these are connected with the the carbohydrate receptors of the pellicle.  Bacterial concentration is also one of the factors for adhesion. While the minimum amount of S. Sangius to hold the plaque is 10000 / ml, this figure is 1000000 / ml for s.Mutans, which means that the sangiants are more successful in adhesion. Plaque: formation and development It depends on the position of the teeth, and the roughness of the tooth surfaces, and hygiene of person  There are 3 phases in plaque formation. Young Plaque: refers to the first colony formation in the initial phase. Mature Plaque: Rapid bacterial growth stage. Remodeling phase: Young Plaque: It occurs within the first 8 hours. In the first 4-5 hours, the first bacteria is the cocoid cocobacillus. They are seen only around the pits and they do not disturb the anatomical image of the enamel. After 8 hours, all pits are completely covered. In this initial phase, we can also see the form of precipitated glycoproteins, food residues with residues of lymphocytes, leukocytes and epithelium residues. In 90% of plaque studies Streptococci and actinomycetes have shown to be premature colony-forming predominant microorganisms. S.mitis and S. sangius are the first precipitated microorganisms on the early soft plaque surface.  2- Moderate Plaque (mature plaque):  Rapid bacterial growing phase: a significant increase in the number of bacteria after 8 hours due to the second day. This does not mean that the bacteria have migrated. They are simply multiplying. After 24 hours the tooth surface resembles the construction area  At the end of the day, the coccus and the filaments are dominant.  In the first 12 hours, the number of streptococci is constantly increasing during the first 12 hours, while the number of actinomycoses is decreasing.  Although there is basic information on this subject, there is no detailed information about microorganism colonization. However, it is thought that the plaque is shaped according to bacteria type and saliva composition and organic deposit type Remodelling Phase:  It is the phase until the end of the secound day that the ending is not obvious until the plaque is eventually removed.  Plaque microorganisms, which are initially aerobes, become aerobe at the upper part and become uneorop in deeper parts day by day.  Coccus and flament dominante in old fissures. Lactobacilli and vionella are also found in a few places.  Sterptococci are relatively fewer in number ant the beginning but as plaque ages, the number of streptococcus mutans will increase. Supragingival plaque: The plaque on which the gingiva does not cover Examined in 4 layers Plaque tooth surface Intensive microbial layer Plain body Plain surface Subgingival plaque: Plaque under the gum: the formation is hard as it is narrow and limited. Fissure plaque: plaque in fissures: very narrow in occlusal surface due to chewing function Supraginival plaque  Plaque tooth surface:  The microbial layer:  Body of Plaque:  Plague surface: Subgingival plaque The plaque under gum; responsible from periodontal desease Fissure Plaque: Plaque formed in fissures : ıts thin in occlusal surface because of chewing function. 7 days later with the help of this funciton this plaque is imlantated to deep fissures with food deposits. Gram positive cocci, sticks and partial gram negative cocci and rods are seen on the plate dominantly but Over time, however, the number of mutants increases with sucrose When the fissures are examined, calculi formation starts from the 7th day. In only one tooth ; Every fissure is a separate ecological environment. If a colonization occurs here, it is difficult for a bacterium to participate in it. For this reason, this information is very important in planning protective procedures. Plaque microorganisms There are various Gr + and Gr- bacteria on the plaque. Bacteria can be found in different places and types depending on the age of the place, the diet, the age of the plaque. The supra gingival plaque has mostly gr + facultative aeorobs. S. sangius, A. viscosus are the most common, followed by S.Mitis, S.Mutans, A.Naeslundi, A. İsraili, Peptostreptococci, S. Epidermis In Gr- site; there are Veillonella Alcalescens, V. Parvula, Fusobacteria and Bacteroides Oralis. At the beginning streptococus are dominant but by time Actinomycetes become dominant Caries Microorganisms ASIDOGENIC BACTERIA: Many dominant organisms on the plaque are able to convert sugar into acids These: Streptococci Actinomycetes Akteriodes, Füzobakteiler Neisseria Veinonella  Gram-positive cocci are seen in the first 2-4 hours of pellicle formation. Gram positive bacilli and filaments are detected within 1-2 days. The number of Actinomyces in the plaque increases over time.  Towards the end of the 19th century, the "chymico- parasitic theory" was put forward by Miller, who claimed that oral microorganisms break down dietary carbohydrates into acids that demineralize enamel. However, since developments in microbiology are still very new, it has not been determined which bacteria(s) are responsible. In 1924, Clarke isolated streptococcus from a human carious lesion and named it S. mutans.  Since the days when microbiology became a discipline, it has been known that dental plaque biofilm has a distinct microflora. Therefore, great progress has been made with the introduction of the "specific plaque hypothesis". According to this hypothesis, among the many types of bacteria found in the dental plaque biofilm, only a few types of bacteria actively cause disease. For this reason, it is thought that caries can be combated if precautions are taken against these specific bacteria that cause the disease.  Streptococcus mutans is a facultatively anaerobic, gram-positive coccus (round bacterium) commonly found in the human oral cavity and is a significant contributor to tooth decay. It is part of the " streptococci", an informal general name for all species in the genus Streptococus. S. mutans is naturally present in the human oral microbiota, along with at least 25 other species of oral streptococci. The taxonomy of these bacteria remains tentative.  Streptococcus mutans and Streptococcus sobrinus play a primary role in the etiology of dental caries due to their adhesion ability to enamel pellicles and other plaque bacteria. Streptococcus mutans are strong acid-producing bacteria and create a risk factor for cavity formation due to the acidic The most environment they create. cariogenic species: According to a study conducted by S.mutans Mayooran et al. in 2000, caries S.sobrinus formation is generally observed within 6-24 months following the appearance of S. mutans in the oral environment.  S.mutans and S. sobrinus, which are acidogenic bacteria, can form extracellular polysaccharides in the presence of sucrose. In addition, they can also use fructose and glucose. Extracellular polysaccharides are polymers with long chains and high molecular masses. The energy-rich glycosidic bond between glucose and fructose moieties provides the free energy required for extracellular polysaccharide (EPS) synthesis.  While glucose homopolysaccharides are called "glucans", fructose homopolysaccharides are called "fructans". Glucans are glycosyltransferase products, while fructans are frucosyltransferase products. Extracellular polysaccharides, produced in large quantities from sucrose, are an important factor for the cariogenicity of S.mutans.  The chemıstry of carıes Dental caries is the irreversible loss of material that occurs as a result of organic acids produced in bacterial plaques. In addition to disturbing the patient for pain and/or aesthetic reasons, their treatments cause an economic burden both individually and socially. Therefore, early diagnosis and treatment of caries is extremely important. Caries should not be seen as a simple mineral loss, but should be considered as a complex event. In order to explain this phenomenon, it is necessary to examine the chemical structures that play a role in tooth decay (Acid formation - Reaction environment - Tooth structure).  Components of a chemical reaction; It can be classified as the reactant (acid), reaction medium and conditions (plaque liquid-tooth), and the reaction product. If reversibility occurs in a chemical reaction, the reaction is reversible; if reversibility does not occur, it is irreversible. In dental caries, the acid in the oral environment and the hard tissues of the teeth react over a period of time, and as a result, caries occur as an initially reversible reaction and later as an irreversible reaction. While the inorganic structure in enamel and dentin is destroyed by acids, the organic structure is destroyed by ferments.  Acids occur in mouth; As a result of the activity of oral bacteria, carbohydrates are broken down, People who have constant contact with acids due to their profession (battery factory workers, laboratory workers, chemists, etc.), breathing acidic air due to air pollution, Some acidic drinks (Cola, some fruit juices, some herbal teas, alcoholic beverages, etc.) due to frequent vomiting in pregnancy and chronic alcoholism, gastric juice coming to the mouth in reflux disease, and some acidic drugs taken by chewing (Aspirin, some effervescent vitamin tablets, etc.). The role of carbonhydrates on caries The compounds that form the first part of the chemical reaction in caries are organic acids. There are three main types of nutrients in our diet. These are proteins, carbohydrates and fats. Apart from these, mineral salts, vitamins and trace elements are present in lesser amounts.  The source of acid in the oral environment is carbohydrates. Increased urbanization has led to the replacement of unprocessed sugars with refined sugars from natural sources, which has led to an increase in caries. The linear relationship between sugar consumption and caries formation in societies has been shown in many studies. Less cariogenic effects of starchy foods and fresh fruits have been reported than other carbohydrate- containing foods. Foods that require extensive chewing stimulate salivation and therefore have low cariogenic potential. Fibrous and firm fruits such as apples and carrots clean the tooth surface like natural toothbrushes.  Replacing fermentable carbohydrates with artificial sweeteners such as xylitol, saccharin, sorbitol, and aspartame has been used effectively to reduce caries. Microorganisms cannot ferment these types of sweeteners and acid formation is either very low or no acid is formed. However, due to the possible carcinogenic effects of artificial sweeteners, their long-term use is not recommended. Beverages such as fruit juices and milk (with sugar) are considered less cariogenic because they do not remain in the oral cavity as long. Consumption of acidic drinks, especially by children, is the most important cause of caries and should be strictly prevented. Monosaccharıdes Glucose (Dextrose), Fructose (Levulose), Galactose etc. molecules are monosaccharides. Monosaccharides, i.e. simple sugars, such as glucose, also known as "grape sugar", and fructose, also known as "fruit sugar", can enter the bacterial plaque because their molecular structures are small, and can be broken down into organic acids by acidogenic microorganisms and initiate caries. dısaccharıdes Maltose, Sucrose, Lactose etc. molecules. Disaccharides are not used directly by bacteria. Disaccharides such as sucrose, known as "tea sugar", lactose, known as milk sugar, and maltose, known as malt sugar, can first be converted into monosaccharides and then into organic acids. If this acid environment is neutralized by the buffering effect of bicarbonate and phosphates in the structure of saliva, plaque does not form on the tooth surface and prevent of caries occurs. polısaccharıdes Starch is one of the main ingredients of floury foods. These larger, macromolecular polysaccharides cannot enter the bacterial plaque due to their structure, and the enzymes that can break them down are not always available in the mouth. Microorganisms can only produce enzymes that can break down mono and disaccharides. In the mouth, only amylase secreted by the parotid salivary gland can break down starch. With the help of amylase, starch can be converted into dextrin, dextrin into maltose, and maltose into monosaccharides. Practically, this takes a very long time. However, polysaccharides are generally swallowed without being broken down much during eating. Anyway, amylase is secreted very little and cannot completely break down the starch. However, if the nutrients are too sticky and remain in the mouth for a long time, caries may occur in areas that cannot be cleaned, such as interdental spaces, fissure bottoms, gingival pockets, etc., where they can easily accumulate. Factors affecting the caries- promoting properties of carbohydrates 1. The type of carbohydrate taken can change the cariogenic effect. For example, the sugars sucrose are more cariogenic than fructose and glucose. Again, if fructose, glucose or sucrose are present in the same food substance, they may have more cariogenic effects than if they were found alone. 2. The physical properties of the carbohydrate taken may change the cariogenic effect. The cariogenicity of the sugar changes whether it remains in the mouth for a short or long time, whether it is hard, sticky, easily or difficult to dissolve, and whether it is in liquid form. 3. Carbohydrates taken outside of normal meals have a more caries- causing effect. Because salivation is higher in normal meals and the number of chewing is higher, it contributes to mechanical cleaning. 4. Apart from carbohydrates, individual factors also affect the rate and severity of caries formation. The amount of saliva, flow rate, anatomical form of the tooth, etc. (Reduction of saliva is important in some diseases)  THE MOST CARIOGENIC CARBONHYDRATE: SUCROSE!!! The most important reason is that it is the most used carbohydrate. In addition, some enzymes produced in plaque, especially by S. Sangius and S. Mutans, are very effective only on sucrose, but cannot affect fructose, glucose, lactose, and maltose. Thus, sucrose; It breaks down into glucan and fructose. Other microorganisms also create organic acid from fructose. Another important feature of sucrose is that it is the source of glucan, a glucose derivative. Glucan can be adsorbed to hydroxyapatite. Most glucans are sticky and insoluble. This feature makes them more resistant to bacteria. Glucans cause the accumulation of specific species of oral bacteria and can be adsorbed to hydroxyapatite, especially S. Mutans, which is agglutinated and aggregated by extracellular glucans. It also facilitates the accumulation of Actinomyces viscosus and S. Sangius. STEPHAN CURVE Stephan’s, experiment was done to study the changes occurring in the pH of the plaque after glucose intake (carbohydrate intake). Stephan performed his experiment on groups of patients with different caries activities ranging from caries resistant patients to caries susceptible patients. An electrode was placed in contact with the plaque and another electrode was placed in the floor of the mouth to measure the resting pH i.e. one hour after meal when there are no fermentable carbohydrates in the oral cavity. Patients were asked to rinse their mouth with 25ml 10% glucose solution for 10 seconds. The pH changes in the dental plaque were recorded frequently and the pH values were plotted against the time and Stephan’s curves were drawn.  The curves show that after the glucose rinse, the pH drops rapidly reaching the critical pH (5.5) within 2-5 minutes (depending on the caries activity of the patients). The pH remains under the critical level for 10-30 minutes (depending on caries activity). Then the pH returns slowly to the resting pH level after one hour THE EFFECT OF SUCROSE ON BIOFILM Sucrose is the most cariogenic carbohydrate in terms of being fermentable as well as serving the formation of extracellular (EPS) and intracellular polysaccharides (IPS). EPS is mainly insoluble glucans, causing bacteria to attach to the tooth surface and contributing to the structural structure of the biofilm layer. It allows the porosity of the biofilm and the diffusion of sugar into deeper layers, and the plaque pH decreases with microbial catabolism. This indicates the critical virulence of sucrose-generated EPS in biofilm formation.  It has been demonstrated in various studies that sucrose reduces the concentration of calcium, fluoride, and inorganic phosphorus in dental biofilm. These ions are very important in maintaining mineral balance between enamel and the oral environment. Low pH and concentration of these ions are important in demineralization and remineralization. The decrease in ions increases the caries potential of the biofilm.  CARIOGENITY Foods that do not lower the oral pH below 5.7 within 30 minutes after being taken into the mouth are considered non- cariogenic (non-cavity- causing).  LIPIDS Lipids in the main food group are esters of fatty acids. Fatty acids are released by the esterase ferment in the plaque and form salts with Ca and Mg in the plaque. They do not affect decay, but the slipperiness they provide to nutrients reduces the adhesion rate.  proteıns It is converted into amino acid and urea, producing ammonia as the final product. Ammonia dissolves easily in water and is converted into ammonium hydroxide, providing an advantage against caries.