Dental caries and dental plaque are among the most common diseases worldwide and are caused by a mixture of microorganisms and food debris. Dental caries is most common chronic disease of childhood and leading cause to the tooth loss to in adult. Dental caries result in the specific bacteria that impact the entire mouth. It is one of the most frequent oral diseases, affecting more than 90% of the population, regardless of age, sex or race. Dental plaque is a soft gelatinous mass adhering to the tooth surface and other hard surfaces and comprising of bacteria embedded in an organic matrix. About 80% of the people in developing countries use traditional medicines for their health care. The natural products derived from medicinal plants have proven to be an abundant source of biologically active compounds, many of which have been the basis for the development of new lead chemicals for pharmaceuticals.
Oral diseases continue to be a major health problem worldwide (Petersen, 2003). Dental plaque is a complex microbial community growing as a biofilm on enamel surfaces. The aetiology of both dental caries (tooth decay) and various forms of periodontal disease has long been recognized to be related to bacterial accumulations and plaque composition (Zaremba, 2001). Dental plaque is a microbial biofilm with high species diversity, embedded in polymers of salivary and bacterial origin, found on the tooth surface (Mombelli, 1995). After isolation of helicobacter pylori form dental plaque, controversies regarding the existence of this bacterium in the dental plaque as a probable secondary reservoir for it have been never ceased (Checchi, 2000). The diverse community of microorganisms found on a tooth surface is known as dental plaque. It is defined clinically as the soft, tenacious deposit that forms on tooth surfaces that is not readily removed by rinsing with water (WHO, 1976).
Dental caries is still one of the most common diseases in the world today. Until recently almost everyone had experienced tooth decay in their lifetime (Birkhed, 1989). Dental caries and periodontal diseases are among the most important global oral health problems, although conditions such as oral and pharyngeal cancers and oral tissue lesions are also significant health concern (Petersen, 2003). The development of dental caries depends on oral bacteria metabolising dietary carbohydrates to produce acid. Although a wide spectrum of acidogenic flora may be involved, Streptcoccus mutans has been most consistently identified as the most significant (Harris, 2004). The notion that dental caries in animals is an infectious, transmissible disease was first demonstrated by Keyes (1960). Since then, a group of phenotypically similar bacteria, collectively known as mutans streptococci, has been implicated as the principal bacterial component responsible for the initiation and the development of dental caries (Loesche, 1986). The tooth surface is unique among all body surfaces in two ways. First, it is a non-shedding hard surface, and, second, this surface is introduced into the human mouth during the first years of life. The earliest point at which the cariogenic mutans streptococci may become established is when the first teeth erupt. Solid surfaces are required for both streptococcal colonization and multiplication (Loesche, 1986).
Dental plaque comprised of diverse microbial community that is embedded in a matrix of host and bacterial polymers and grows as biofilm (Marsh, 2003). Mature dental plaque which comprised of a high microbial density community with a variety of micro-organism (Socransky and Haffajee, 2002) is consider to contribute as a major etiologic factor in the formation, development and progression of gingivitis and peridontits (Kornmann, 1986). Dental caries is tooth of decay by the acid production of bacteria residing inside the dental plaque caries extension enough to expose the pulp sensitivity and cause the pain. Advance caries cause the infection. Some of the dental caries include inadequate oral hygiene, infrequent dental examination and cleansing, salivary gland dysfunction frequent snacking and removal frequent dentures which can trap plaque around teeth and create environment conducive to caries formation (PATRO 2008). Many attempts have been made to isolate a specific organism responsible for decay but reports have only been conflicting.
The development of dental caries involves acidogenic and aciduric Gram-positive bacteria, primarily the mutans streptococci (Streptococcus mutans and S. sobrinus), lactobacilli and actinomycetes, which metabolize sucrose to organic acids (mainly lactic acid) that dissolve the calcium phosphate in teeth, causing decalcification and eventual decay. Dental caries is thus a supragingival condition (Loesche, 1986). Dental caries is a multifactorial, bacterial disease, which is characterized by the demineralization of the inorganic portion and the destruction of the organic substance of the tooth (Tanzer, 1992). Lactobacilli and yeasts are commonly associated with caries and their presence has been associated worldwide sugary diet (Beighton, 1996).
Several Gram-positive and Gram-negative bacterial genera are found in the oral cavity. Among the Gram-positive ones are Enterococcus, Peptostreptococcus, Streptococcus, Staphylococcus, Actinomyces, Corynebacterium, Eubacterium, and Lactobacillus species, whereas Aggregatibacter (formerly Actinobacillus), Haemophilus, Bacteroides, Campylobacter, Leptotrichia, Prophyromonas, Capnocytophaga, Prevotella, Tannerella, Eikenella, Treponema, Fusobacterium, and Wolinella species are among the Gram-negative ones (Marsh, 2000). In order to decrease the prevalence of caries, an improved understanding of the role of the microorganisms in dental diseases is needed development of dental caries and periodontal disease. The surface of Gram-positive streptococci is a complex mosaic of many different molecules,including peptidoglycan, lipoteichoic acid, polysaccharides and proteins. It is this surface that comes into contact with oral surfaces including the teeth or more correctly the acquired pellicle composed of salivary deposits on the tooth enamel. As bacteria in any ecosystem need to adhere to survive, attachment is the primary function for streptococcal colonization of the tooth surface (Bowen, 1991).
Streptococcus sanguinis, a normal inhabitant of the human oral cavity, has low cariogenicity, though colonization on tooth surfaces by this bacterium initiates aggregation by other oral bacteria and maturation of dental plaque. Streptococcus sanguinis (formerly S. sanguis) is a member of the viridans group of streptococci (Swenson, 1982). It is the first bacterium to colonize tooth surfaces, where it functions as a pioneer by forming dental plaque, which leads to dental caries, periodontal diseases, and alterations of dental restorations (Kolenbrander, 1993). Streptococcus mutans is regarded as the primary etiologic agent of human dental caries and resides in the oral biofilm dental plaque. To adhere to tooth surfaces in dental plaque and to survive, S. mutans produces several extracellular proteins or enzymes (Ferretti and Okahashi, 1989). Mutans streptococci and lactobacilli are strong acid producers and hence cause an acidic environment creating the risk for cavities (Tanzer, 2001).
Gingivitis is a chronic inflammatory process limited to the gingival and without either attachment or alveolar bone loss (Villalobos, 2001). Mutans streptococci colonize the host only after the first teeth erupt, and their preferential colonization site is the teeth they are highly localized on the surfaces of the teeth, and their abundance in the plaque is highest over initial lesions their level of colonization within the plaque is increased by sucrose consumption; they synthesize certain macro-molecules from sucrose that foster their attachment to the teeth they are rapid producers of acid from simple carbohydrates, including sucrose, and are tolerant to low pH and they are essentially always recovered on cultivation of initial and established carious lesion sites.
Dental caries, as it is well known, involves essentially the dissolution and disintegration of the enamel and dentin. This is generally believed to be caused by the action of acid producing bacteria and their products. MS can ferment various sugars to produce lactic acid. Lactate dehydrogenase (LDH) enzymes convert propionate to lactate, but when carbohydrate is limited these bacteria produce formate, acetate and ethanol. It seems lactic acid is the most important acid involved in the aetiology of dental caries because it is the strongest acid produced in large quantities by the MS. Dietary sugars other than sucrose, for example glucose and lactose, can also induce caries formation. However, these sugars are less cariogenic than sucrose, because, in addition to being converted to acidic metabolites, sucrose is also uniquely utilized for extracellular polysaccharide synthesis. Starch is less cariogenic than other dietary sugars because it does not readily diffuse into plaque and is less readily hydrolyzed (Horton, 1985). It has been demonstrated that S.sobrinus is more acidogenic and more highly cariogenic than the other MS (De Soet, 1989). No one type of acid-producing bacteria has yet been shown to be responsible for the carious lesion. Specific type of acid-producing bacteria, especially Streptococcus mutans, colonize the dental surface and cause damage to the hard tooth structure in the presence of fermentable carbohydrates e.g., sucrose and fructose (Sofia et al., 2010). Dental caries is a disease, which leads to destruction of the tooth structure and ventually to infection of the dental pulp and even surrounding tissues.In the late stages it causes severe pain, is expensive to treat and leads to loss of precious man-hours. However, it is preventable to a certain extent. Secondary caries formation depends on the interaction of the sealing stability of the restoration and the microenvironmental conditions of the oral cavity. The lack of marginal integrity in either enamel or dentin induced by polymerization shrinkage of resin-based materials should be counteracted (Savarino, 2008). Microleakage is the penetration of fluids, bacteria, toxins, ions and other molecules that can be observed at the tooth-restoration interface. During the past few years, considerable efforts have been focused on the development of new adhesives to prevent secondary caries and restoration failures (Prati and Pashley, 2000). Marginal breakdown and microleakage due to polymerization shrinkage of resin-matrix composite occur if the bonding system is not able to prevent postcuring composite shrinkage (Prati and Nucci, 2004). Since the micromechanical adhesion to dentin takes place with the formation of the hybrid layer.
MS can grow at low pH values, some strains even growing at less than pH 4. These streptococci produce large amounts of a membrane-associated ATPase, capable of functioning at low pH, which helps to pump H+ ions from the cell and thus reduce intracellular acidification (Carlsson, 1989).
Prevalence of dental caries
At present, the prevalence of dental caries in India is approximately 60-65% while the prevalence of periodontal disease is approximately 65-100%. In dental practice ,mechanical removl procedure are used to remove dental plaque. However, today many people are caries free and there has been a 40-60 % reduction in the incidence of tooth decay around the Western world. Most developed countries and many non-industrialised countries are now well below the World Health Organisation goal of less than 3 decayed, missing or filled teeth per 12year old child (Birkhed, 1989). However it has been reportd that chemotherapetuic agent ora rinse could act as an adjuvent to mechanical removing of supragigival plaque (Robert and Addy 1981). Among the persons studied with different dietary habit, we found the highest number of caries patients with vegetarian dietary habit (P=0.856) followed by vegetarian plus tobacco user (P=0.077) and non vegetarian (Mixed diet) (P=0.067), respectively. Putrefaction is the result of protein consumption, so it might be suggested that the persons who consume plenty of protein rich food in comparison to sugar, will develop less amount of acid in their mouth and relatively be protected from dental caries. It might be the reason for less number of cases among the non vegetarian (Mixed diet) population. Among the different age group studied we found highest number of cases in between 21 to 30 year peoples. The prevalence of dental caries in the age-group of 35-44 years in the present study was found to be 82.4%, which is lower than that reported in the WHO Oral Health Country Profile (94%).The prevalence of dental caries in the age-group of 60 years and above in this study was 91.7%. It might be suggested that, the development of dental caries is a long term process, and the habit of sugar consumption is relatively high among the teenagers (In the form of chocolates and other sticky sugar rich food), but the peoples usually don’t attend the hospitals, until and unless they feel unbearable pain in the mouth. So we have found most number of dental caries patients among this group. But the number of cases continually increased up to the age of 21–30 (P=0.269) and later on these cases got declined.
Microorganism Present in Oral Cavity
Dental caries is a multifactorial disease usually associated with increased numbers of S. mutans at the site of infection. Although a wide spectrum of acidogenic flora may be involved, Streptoccus mutans has been most consistently identified as the most significant (Harris et al., 2003). Lactobacilli and yeasts are commonly associated with caries and their presence has been associated with sugary diets (Beighton et al., 1996). Dental caries is an infectious microbial disease that results in localised dissolution and destruction of the calcified tissues of the teeth (Ross, 1994). Humans in different parts of the world developed certain oral habits. Smoking, coca leaves chewing in central and South America, betel quid chewing in Southeast Asia, and\ khat chewing in Yemen and East Africa are examples. Such habits have implications for oral health. Smoking, for example, is an established risk factor of periodontitis; approximately half of periodontitis cases have been attributed to either current or former smoking and up to 90 percent of refractory periodontitis patients are smokers (Trivedy et al., 2002).
Dental caries will not occur if the oral cavity is free of bacteria. These bacteria are organised into a material known as dental plaque which is yellowish coloured film on the surface of the teeth. Of the many types of bacteria in the mouth, the most caries active appear to be Streptococcus mutans, Lactobacillus spp., Veillonella spp. and Actinomyces spp. These bacteria can be transferred from mother to child and are present at varying levels in all human mouths. A variety of carbohydrates provide substrates for these organisms to grow on and the waste products of their metabolism – acids – initiate the tooth decay process by dissolving tooth enamel. Most research on the bacteriology of dental caries has focused on the ubiquitous S. mutans and its ability to ferment sucrose. This organism preferentially ferments sucrose to produce significant amounts of acid and extracellular polysaccharide (plaque). However, most researchers now agree that other organisms present in the mouth are capable of plaque formation and acid production from a variety of fermentable carbohydrate substrates besides sucrose which are present in the normal mixed diet (EDGAR, 1993). Lactobacilli do not avidly colonize the teeth; they may be transiently found in the mouth before the teeth erupt. Longitudinal and case-control studies were perhaps more informative. Lactobacilli are late colonizers of the mouth. (Babaahmady, 1998). Lactobacilli are recovered from carious lesions, but they are later colonizers of those lesions than the mutans streptococci. Some data suggest that they are favored in their ability to colonize by pre-existing colonization by the mutans streptococci, especially S. sobrinus. These data thus indicate that lactobacilli are not requisite for the development of lesions .Streptococci mutans is found commonly in man, while Streptococci sobrinus and is carried by 8-/35% of people in different countries. Although Streptococci mutans and Streptococci sobrinus can be distinguished by appropriate laboratory tests, they are expensive and time-consuming. Therefore it is not always considered practical to identify down to the species level in large scale epidemiological studies (Slots and Taubman, 1992; van Ruyven et al., 2000).
Mutans streptococci and Lactobacillus spp. which are the main aetiologic agents of dental caries in humans were observed only sporadically in preschool children. Actinomyces spp. was detected only in dental plaque of children without caries. The proportion of cariogenic bacteria is about 10% and was comparable (p>0.05) in dental plaques in children with and without dental caries in both the preschool and school children Gram-positive bacilli other than Lactobacillus spp. and Actinomyces spp. accounted for about 60% of the total Gram-positive anaerobic rods as well as in carious lesions of primary and permanent teeth. An intensive study of the possible relation of Lactobacillus acidophilus to dental caries has been made by Bunting and co-workers (Bunting, 1933). They have concluded that dental caries is a specific bacterial disease and that L. acidophilus is the chief etiologic agency. Strep. mutans and lactobacilli have both been found produce to the acid from the carbohydrate. Among the lactobacillus spp., L. casei, L .fermentum and L .rhamnosus have been reported in plaque and lactobacilli gernally grow in the acidic inter and interadental space. Mutans streptococci colonize the host only after the first teeth erupt and their preferential colonization site is the teeth (Carlsson, 1975). They are highly localized on the surfaces of the teeth and their abundance in the plaque is highest over initial lesions (Babaahmady 1998); their level of colonization within the plaque is increased by sucrose consumption (Staat, 1975); they synthesize certain macro-molecules from sucrose that foster their attachment to the teeth; they are rapid producers of acid from simple carbohydrates, including sucrose and are tolerant to low pH (Tanzer, 1989) and they are essentially always recovered on cultivation of initial and established carious lesion sites (Keene, 1974). Interest in them grew after the demonstration of their potency in induction and progression of carious lesions in a variety of experimental animals, including mono-infected gnotobiotes.
Their virulence expression is strongly associated with consumption of carbohydrates, especially sucrose (Kuramitsu, 1993). To achieve sufficiently low levels of plaque to support a healthy tooth several mechanical and chemical oral hygiene aids are necessary in addition to the toothbrush. The final result, caries to be or not to be, is a complex phenomenon involving internal defense factors, such as saliva, tooth surface morphology, general health, and nutritional and hormonal status, and a number of external factors-for example, diet, the microbial flora colonizing the teeth, oral hygiene, and fluoride availability. Mechanical methods usually used in dental care services to remove plaques are time consuming and never completely effective (Gonzalez Begne et al., 2001). Chemical approaches including use of antimicrobials, pH modifiers and many others alone or in combination with toothbrush and dental floss provide the best and reliable method in caries prevention (Xiao et al., 2006). Strongly active substances like chlorhexidine gluconate 0.2% mouth rinse (CHX) are capable of reducing the percentage of cultivable microorganisms in the dental biofilm to 0.002%. But it should not be forgotten that some side-effects are present when CHX is used for extended periods of time such as staining of the tongue and of the dental biofilm, perturbation of the taste, burning sensations or mucosal erosion. The single and best way to remove harmful plaque from teeth and gums is to brush teeth regularly and properly. Brushing with toothpaste help to remove the plaque, resist decay and remineralizion clean and polish teeth. A number of anti plaque agent in the dental cream has been formulated and evaluated for the removal of dental plaque (BATWA 2006).
Prevalence of Bacteria
There are 300-plus species of bacteria in the non-cultivable normal oral flora in humans i.e. those which at present cannot be grown in the laboratory, but can be identified by molecular methods and many of these are found in significant numbers in cariogenic biofilms (Wall-Manning, 2002).The main bacterial species associated with this disease are S. mutans and S. sobrinus. Since the attachment and proliferation are key steps in successful colonization in the dental plaque biofilm and pathogenesis of these microorganisms, different strategies such as inhibition of bacterial growth and prevention of microbial colonization were developed to protect the dental caries.
Lactobacilli are highly acidogenic organisms, and early work implicated lactobacilli in the initiation of dental caries. Subsequent research has shown that they are associated more with carious dentine and the advancing front of caries lesions rather than with the initiation of the disease. Usually lactobacilli comprise less than 1% of the total cultivable micro flora. However, their proportions and prevalence may increase at advanced caries lesions both of the enamel and of the root surface.
Streptococci are most predominant microbes in mouth. These are sphere-shaped bacteria. They convert sugars & other carbohydrates into lactic acid. This acid then dissolves tooth enamel, eventually forming a cavity. Streptococcus mutans is the major culprit in forming cavities.
Actinomyces (Actinomyces viscosus)
They contribute along with other organisms to the pathogenesis of dental caries & periodontal disease. Many laboratory studies have employed Streptococcus Mutans as a test organism because of its central role in the etiology of dental caries. In fact, the growth, glucose uptake and acid production of this bacterium are strongly inhibited by the peroxidase system. For Streptococcus mutans, the inhibition is usually reversible.
Nevertheless, bactericidal action has been reported against some enteric bacteria such as Escherichia Coli and Salmonella typhimurium. This type of killing is enhanced by the increased permeability of the cell envelope. The susceptibility to of many species of oral bacteria to inhibition by the peroxidase system is partly dependent on their own H2O2 production, and partly due to the presence of an enzyme within the microorganism itself. In short, the Peroxidase System has, compared to the other antiseptic molecules, the advantage of selecting and safeguarding the beneficial oral flora, of killing or inhibiting the harmful flora and thus regulating oral conditions. An ideal antimicrobial agent would inhibit both of these activities. Antimicrobial susceptibility of oral has been tested to a number of plant extracts and natural substances (Xiao et al., 2006; Didry et al., 1998).
Protective Role of Saliva
Saliva is remarkably protective against decay, as is evident by the rampant decay that ensues when salivary flow is very low, i.e. in xerostomia patients, and by the fact that decay is a relatively minor health problem in the absence of frequent sucrose consumption. When food is masticated, salivary flow increases, which not only serves to prepare the bolus for swallowing, but also provides both a large liquid volume for plaque acids to diffuse into and an increased concentration of bicarbonate buffer to neutralize these acids .The saliva also contains pH rise factors such as urea and a tetrapeptide called sialin which contains lysine and arginine .The hydrolysis of these basic compounds by certain members of the plaque flora liberates ammonia, causing the pH to rise .The saliva and the fluid phase of plaque are supersaturated with respect to calcium and phosphate ions .This means that the environment of the tooth surface actually favors mineral deposition, and if saliva were an ordinary fluid, the tooth would be encrusted with ectopic calcium phosphate deposits. The saliva contains certain proline-rich proteins and an unusual tyrosine-rich peptide, called statherin, which in vitro delays both the onset and rate of precipitation of calcium phosphate salts from supersaturated solutions .The maintenance of the supersaturated state of these ions provides a constant and powerful remineralizing mechanism on those surfaces that are bathed by saliva. The main oral innate defense factors are the peroxidase systems, lysozyme, lactoferrin, and histatins. In vitro, these proteins are known to-
(1) Limit bacterial or fungal growth
(2) interfere with bacterial glucose uptake or glucose metabolism
(3) Promote aggregation and, thus, the elimination of bacteria
It should be emphasized that, in addition to the antimicrobial action of both salivary peroxidase and myeloperoxidase systems (Mansson-Rahemtulla et al, 1987), one of the main purposes of these systems is to eliminate H2O2, which is highly toxic for mammalian cells (Hanstrom et al., 1983) .Many of the antimicrobial defense systems in saliva are common to all exocrine secretions such as tears, milk, and seminal, vaginal, and gastrointestinal fluids .Especially lysozyme, lactoferrin, and peroxidases are present in measurable concentrations in all these secretions. These antimicrobial agents are mainly synthesized in, and secreted via, the major or minor salivary glands, but a smaller amount enters the oral cavity from tissue fluid or polymorphonuclear leukocytes (PMNs) via the gingival crevicular fluid (Tenovuo and Lumikari, 1991). The immunoglobulins, IgG, IgM, IgA, and secretory IgA (slgA), form the basis of the specific salivary defense against oral microbial flora, including mutans streptococci. The most abundant Ig in saliva, as in all other human secretions, is dimeric slgA, which is produced by plasma cells located in the salivary glands. Two IgA subclasses are present in saliva; IgAl forms the major component of Igs, although the relative amount of IgA2 is higher in saliva than in other secretions (Tappuni and Challacombe, 1994)
Dental caries can potentially be prevented by interfering with transmission of MS, eliminating established MS populations from the oral cavity, increasing the acid-resistance of the teeth and control of the carbohydrate composition of the diet. Vaccines have been spectacularly successful in protecting entire populations against infectious disease and their application to caries prevention would seem logical and timely. Researchers have taken three broad approaches to the development of anti-caries vaccine.
Medicinal plants have been used as traditional treatments for numerous human diseases for thousands of years and in many parts of the world. In rural areas of the developing countries, they continue to be used as the primary source of medicine (Chitme, 2003). About 80% of the people in developing countries use traditional medicines for their health care (Kim, 2005). With respect to diseases caused by microorganisms, the increasing resistance in many common pathogens to currently used therapeutic agents, such as antibiotics and antiviral agents, has led to renewed interest in the discovery of novel anti-infective compounds. As there are approximately 500000 plant species occurring worldwide, of which only 1% has been phytochemically investigated, there is great potential for discovering novel bioactive compounds. There have been numerous reports of the use of traditional plants and natural products for the treatment of oral diseases. Many plant-derived medicines used in traditional medicinal systems have been recorded in pharmacopeias as agents used to treat infections and a number of these have been recently investigated for their efficacy against oral microbial pathogens. The general antimicrobial activities of medicinal plants and plant products, such as essential oils, have been reviewed previously (Kalemba, 1993). The largest components of the Punica granatum L. fruit extract are tannin and polyphenolics .There is a growing interest in using tannins as antimicrobial agents in caries prevention (Haslam E. 1996).The action of tannins against bacteria and yeasts can be established by a relation between their molecular structure and their toxicity, astringent properties or other mechanisms. The effect of tannins on microbial metabolism can be measured by their action on membranes. They can cross the cell wall, composed of several polysaccharides and proteins, and bind to its surface. This adhesion can also help determining minimum inhibitory concentrations for yeasts and bacteria.
Dental caries is one of the most common and costly diseases in the world and although rarely life threatening it is a major problem for health service providers. Dental caries is an ecological disease in which the diet, the host and the microbial flora interact over a period of time in such a way as to encourage demineralisation of the tooth enamel with resultant caries formation. Dental caries and periodontal disease i.e. gingivitis and periodontitis are the most common chronic oral diseases in the world. Dental caries is an infectious microbial disease that results in localized dissolution and destruction of the calcified tissues of the teeth. The purpose of this review is to present some recent examples from the literature that have served to validate the traditional use of medicinal plants with specific biological activity. In particular, traditional medicinal plant extracts or phyto-chemicals that have been shown to inhibit the growth of oral pathogens, reduce the development of dental plaque, influence the adhesion of bacteria to surfaces and reduce the symptoms of oral diseases can used against the dental carries and as well as dental plaque.
The author is most grateful to K.P. Rathoure (Mrs) for her technical and valuable comments.
Beighton, D., Adamson, A. and Rugg-Gunn, A. (1996), Associations between dietary intakes, dental caries experience and salivary bacterial levels in 12-year-old English schoolchildren.Archives of Oral Biology 41, 271–280.
Birkhed D., Sundin B., Westin S.I., (1989), Per capita consumption of sugar containing products and dental caries in Sweden from 1960 to 1985. Comm. Dent. Oral Epid. 17: pp 41-43.
Bowen WH, Schilling K, Giertsen E, et al. (1991), Role of a cell surface associated protein in adherence and dental caries. Infect Immune, 59:4606-9.
Checchi L, Felice P, Acciardi C, Ricci C, Gatta L, Polacci R, et al. (2000), Absence of Helicobacter pylori in dental plaque assessed by stool test., Am J Gastroenterol 95:3005-6.
Harris RV., Nicoll AD., Adair PM., Pine CM., (2004): Risk factors for dental caries in young children: a systematic. Community Dental Health 21.
Loesche WJ., (1986), Role of Streptococcus mutans in human dental decay. Microbiol Rev 50:353-380.
Marsh PD., (2000), Oral microbial diversity. In: Ellen RP, Kuramitsu HK, editors. Oral bacterialecology: the molecular basis. Wymondham,: Horizon Scientific Press; p. 11-65.
Mombelli A, Nyman S, Bragger U, Wennstrom J. (1995), Clinical and microbiological changes associated with analtered subgingival environment induced byperiodontal pocket reduction. J Clin Periodontol, 22: 780-787.
Petersen P. E., (2003), The World Oral Health Report 2003: continuous improvement of oral health in the 21st century, the approach of the WHO Global Oral Health Programme, Community Dentistry and Oral Epidemiology, vol. 31, pp. 3– 24
Swenson F.J., Rubin S.J., (1982), Clinical significance of viridans streptococci isolated from blood cultures, J. Clin. Microbiol. 15:725e727.
Tanzer, J.M., 1992. Microbiology of dental caries. In: Contemporary Oral Microbiology and Immunology. Mosby, St. Louis.
Tanzer, J.M.; Livingston, J., Thompson, A.M., (2011), The microbiology of primary dental caries in humans. J. Dent. Educ. 65: 1028-1037.
Villalobos OJ, Salazar CR, Sánchez GR. (2001), Efecto de un enjuague bucal sssscompuesto de aloe vera en la placa bacteriana e inflamación gingival. Acta Odontol Venez, 39:16-24.
Zaremba ML, Borowski J. (2001), Mikrobiologia lekarska. Warszawa, Wydawnictwo Lekarskie PZWL, wyd. 3.
About the Author:
Dept of Biotechnology, Himachal Institute of Life Sciences Rampurghat Road, Paonta
Sahib -173025, Himachal Pradesh, INDIA
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Dr. Ashok Kumar C/O Mr. G.K. Rathoure, MAYASHIVRAJ SADAN, Gupta Colony, Railway Ganj Hardoi-241001 (UP) INDIA,
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