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Dental Caries 2 Introduction Dental caries (tooth decay) is an infectious bacterial disease that has plagued human beings since the beginning of recorded history Today, because of scientific advances and new technologies, dentistry is developing new strategies for managing dental caries These strategies emphasize prevention and early intervention 3 Bacterial Infection Two specific groups of bacteria found in the mouth are responsible for dental caries: Mutans streptococci (MS) (Streptococcus mutans) (strong disease causing) Lactobacilli (LB) They are found in relatively large numbers in dental plaque The presence of lactobacilli in the mouth indicates a high sugar intake 4 Transmission of Caries-Causing Bacteria Mutans streptococci are transmitted through saliva, most frequently the mother’s, to the infant When a mother has a high count of mutans streptococci in her mouth, the baby has a high count of the same bacteria in his or her mouth Women should be certain that their own mouths are healthy When the number of caries-causing bacteria in the mouth increases, the risk of dental caries also increases 5 Dental Plaque Dental plaque is a colorless, soft, sticky coating that adheres to the teeth Plaque remains attached to the tooth despite movement of the tongue, water rinsing, water spray, and less-thanthorough brushing Formation of plaque on a tooth concentrates millions of microorganisms on that tooth 6 Dental Plaque 7 Enamel Structure Enamel is the most highly mineralized tissue in the body It is stronger than bone Enamel consists of microscopic crystals of hydroxyapatite arranged in structural layers or rods, also known as prism The enamel crystals are surrounded by water The water and protein components in the tooth are important because that is how the acids travel into the tooth, the minerals travel out, and the tooth structure dissolves 8 The Caries Process For caries to develop, three factors must be present at the same time: A susceptible tooth A diet rich in fermentable carbohydrates Specific bacteria (regardless of other factors, caries cannot occur without bacteria) 9 10 Areas for Development of Caries Pit-and-fissure caries occurs primarily on the occlusal surfaces and the buccal and lingual grooves of posterior teeth, as well as in the lingual pits of the maxillary incisors Smooth surface caries occurs on intact enamel other than pits and fissures Root surface caries occurs on any surface of the root Secondary, or recurrent, caries occurs on the tooth surrounding a restoration 11 Stages of Caries Development It usually takes some time, months to years, for a carious lesion to develop Caries is an ongoing process characterized by alternating periods of demineralization and remineralization It Demineralization is the dissolution of the calcium and phosphate from the hydroxyapatite crystals Remineralization is the redeposition of calcium and phosphate in previously demineralized areas is possible for the processes of demineralization and remineralization to occur without any loss of tooth structure 12 Demineralization and Remineralization 13 Stages of Caries Development An incipient lesion (a watch) develops when caries begins to demineralize the enamel An overt, or frank, lesion is characterized by cavitation (the development of a cavity or hole in the tooth) Rampant caries describes the time between the onset of the incipient lesion and the development of the cavity; it is rapid and there are multiple lesions throughout the mouth 14 Early Carious Lesion, or White Spot of Demineralization Courtesy Dr. John D.B. Featherstone, School of Dentistry, University of California San Francisco. 15 Overt Carious Lesion Courtesy Dr. Frank Hodges, Santa Rosa, CA. 16 Rampant Caries Courtesy Dr. Frank Hodges, Santa Rosa, CA. 17 Severely Decayed Molar on a Child 18 Decay on the Lingual Surface of a Maxillary Lateral Incisor 19 Secondary (Recurrent) Caries Form in the spaces between the teeth and margins of a restoration Not easily seen, thus diagnosis is difficult New restorative materials may prevent recurrent decay 20 Root Caries Occurs on the root of teeth that have gingival recession that exposes root surfaces Becoming more prevalent and is a concern for members of the elderly population, who often have gingival recession, exposing the root surfaces Older people often take medications known to reduce saliva flow, which contributes to caries Carious lesions form more quickly on root surfaces than coronal caries does because the cementum on the root surface is softer than enamel and dentin Like coronal caries, root caries has periods of demineralization and remineralization 21 Recurrent Decay 22 Root Surface Caries Courtesy Dr. John D.B. Featherstone, School of Dentistry, University of California San Francisco. 23 Early Childhood Caries (ECC) An infectious disease that can happen in any family Many children live with the constant pain of decayed teeth and swollen gums In some states ECC affects one third of preschool children Tooth decay is the single most prevalent disease of childhood Early childhood caries can be prevented with appropriate education of the parents and oral health care for the child 24 Risk Factors for ECC ECC is common among families of lower socioeconomic status The rate of untreated dental disease among lowincome children aged 2 to 5 years is almost five times higher than that seen in higher-income families ECC is more common among: Particular ethnic groups In those families who have limited access to dental care In areas where water fluoridation is lacking ECC is also more common among children with special needs 25 How Children Get Early Childhood Caries ECC It is a transmissible disease Bacteria in the parent’s or caregiver’s mouth are passed to the child is important for parents to keep their own teeth healthy to keep their children’s teeth healthy Baby bottle tooth decay is another term for ECC 26 The Importance of Saliva Physical protection involves a cleansing effect Chemical protection contains calcium, phosphate, and fluoride Thick, or viscous, saliva is less effective than a more watery saliva in clearing carbohydrates Keeps calcium at the ready, to be used during remineralization Chemical protection includes buffers, bicarbonate, phosphate, and small proteins that neutralize the acids after we ingest fermentable carbohydrates Antibacterial substances in saliva work against the bacteria If salivary function is reduced for any reason, the teeth are at increased risk for decay 27 Caries Diagnosis The following methods are used to detect dental caries, and each has specific limitations: Dental explorer Radiographs Visual appearance Indicator dyes Laser caries detector 28 Caries Detection Devices Several types of devices have been developed that can provide a higher level of discrimination in the diagnosis of dental caries Some detect bacterial by-products and quantify sound signals to aid in caries detection Some detect differences in tooth structure and display information on a screen Others have software that analyzes density changes on digital radiographs and outlines potential lesions 29 Laser Caries Detector Used to diagnose caries and reveal bacterial activity under the enamel surface Carious tooth structure is less dense and gives off a higher reading than noncarious tooth structure 30 The DIAGNOdent Courtesy KaVo Dental, Charlotte, NC. 31 Visual and Radiographic Appearance of Molar Courtesy KaVo Dental, Charlotte, NC. 32 Cross Section of Molar Showing Decay Courtesy KaVo Dental, Charlotte, NC. 33 CAMBRA Caries management by risk assessment An evidence-based strategy for preventive and reparative care for early dental caries that can be used in any dental office A dental health professional assesses an individual’s risk factors, and protective factors, then determines the level of risk for caries An individualized preventive plan is developed based on the determined level of risk 34 Methods of Caries Intervention Fluoride: A variety of types are available to strengthen the tooth against solubility to acid Antibacterial rinses: Products such as chlorhexidine rinses are effective Decreased fermentable carbohydrates: Reduce the amount and frequency of ingestion Increased salivary flow: Chewing sugarless gum—for example, one with a nonsugar sweetener such as xylitol 35 Preventive Measures Against Caries 36 Caries Risk Assessment Tests Used to identify the factors that contribute to an increased risk for dental caries If the patient’s risk for dental caries can be determined, it is possible to prevent the caries from developing by beginning appropriate preventive treatment Risk-assessment tests for caries are based on the amount of mutans streptococci and lactobacilli present in the saliva High bacterial counts indicate a high caries risk, and low counts indicate a low risk for caries 37 Patients in Whom a Caries-Risk Test Is Indicated New patients with signs of caries activity Pregnant patients Patients experiencing a sudden increase in the incidence of caries Individuals taking medications that may affect the flow of saliva Xerostomic patients 38 Patients in Whom a Caries-Risk Test Is Indicated Patients about to undergo chemotherapy Patients who frequently consume fermentable carbohydrates Patients suffering from diseases of the autoimmune system