Dental caries is the most common chronic disease of childhood and the most prevalent unmet health need of US children. Largely a disease of poverty, dental caries affects almost 80% of children and adolescents living in low-income families.
Formerly termed “baby bottle tooth decay” or “nursing bottle caries,” early childhood caries is a particularly virulent and rapidly progressive form of caries that begins on the smooth surfaces of the teeth soon after eruption. ECC is defined as one or more decayed (d), missing (m), or filled (f) tooth surfaces (s) in any primary tooth in a child under 6 years of age. The disease typically involves the maxillary incisors, but any other teeth may be affected. A lack of adequate preventive care and poor feeding habits can place children at high risk for ECC.
Any sign of smooth-surface caries in a child less than 3 years is termed severe ECC (S-ECC). From 3 to 5 years, a dmfs score of 1 or more in maxillary front teeth or a total dmfs score of 4 or higher must be present to make a diagnosis of S-ECC. Children with S-ECC are at higher risk for new carious lesions. They are also likely to experience frequent hospitalizations, emergency department visits, and school absences due to the severity of existing carious lesions. The presence of S-ECC can also result in below-normal height and weight gain and diminished oral health-related quality of life for the affected child. Although S-ECC can affect all children, it is 32 times more likely in children who consume sugary foods and whose mothers are of low socioeconomic status and education level.
Development of caries requires the interaction of four factors: (1) a host (tooth in the oral environment); (2) a suitable dietary substrate (fermentable carbohydrates); (3) cariogenic microorganisms that adhere to the tooth; and (4) time, measured as the frequency of exposure to fermentable carbohydrates and the duration of acid exposure. The main organisms implicated in the initiation of caries are MS and Streptococcus sobrinus. Lactobacillus acidophilus and Lactobacillus casei are also linked to the progression of caries. MS organisms are most commonly passed from mother to child. A “window of infectivity” between ages 19 and 30 months has been described, but MS colonization of the oral cavity can occur as early as 3 months of age. Earlier colonization increases the risk of caries.
Dental plaque is an adherent biofilm on the tooth surface that harbors acidogenic bacteria in close proximity to the enamel. As bacteria metabolize sucrose, they produce lactic acid that solubilizes calcium phosphate in tooth enamel. Demineralization of the dental enamel occurs below pH 5.5 and is the first step in cariogenesis. The flow rate of saliva and its buffering capacity are important modifiers of demineralization. Demineralization of enamel and dentin can be halted or even reversed by redeposition of calcium, phosphate, and fluoride from saliva.
If caries progresses it penetrates the enamel, advancing through the dentin toward the pulp of the tooth. In response, blood vessels in the pulp dilate and inflammatory cells begin to infiltrate (pulpitis), resulting in tooth pain. When the carious lesion is still untreated, pulp invasion will occur, triggering invasion of more inflammatory cells and the eventual formation of a small pulpal abscess. Once the pulp in the root of the tooth becomes necrotic, a periapical abscess develops (Figure 17–7) which usually causes severe pain, fever, and swelling.
Tooth anatomy and progression of caries.
Prevention of dental caries necessitates restoration of the delicate balance between pathologic and protective factors. Pathologic factors include cariogenic bacteria and fermentable carbohydrates. Protective factors include salivary flow and fluoride in food, beverages, drinking water, and oral care products. Saliva contains calcium, phosphate, proteins, and antibacterial substances; it also buffers acid produced by bacteria in plaque.
The concept of prevention through timely and regular parent education, early diagnosis, and prompt intervention offers greater efficiency, better health outcomes, and lower costs than repeated restoration of diseased teeth. In this regard, the primary care physician plays an invaluable role since parents are more likely to take their very young child to a physician for well-child visits than to a dentist for oral health counseling. Some states have established formal programs to entice medical offices to provide preventive dental services that include dental screening, caries risk assessment, parent counseling about their child’s oral health, and referrals to dentists as needed.
The development of dental caries requires frequent exposure to fermentable carbohydrates. Poor feeding habits that place children at higher risk for ECC include the frequent consumption of sugar-containing beverages from a nursing bottle, frequent sipping from a no-spill sippy cup, taking a bottle to bed, and frequent ad libitum breast-feeding. Each such exposure produces an acidic oral environment for up to 30 minutes and propagates the caries process.
Infants should be weaned from the bottle between 12 and 18 months of age and encouraged to drink from an uncovered cup (rather than a no-spill training cup). Parents must also be advised to limit the frequency of their child’s consumption of sugar-containing snacks between meals. As parents are involved in helping feed their child at the infant and toddler stages of development, they should be counseled to eliminate saliva-sharing activities (eg, sharing spoons during meals) to minimize the transmission of cariogenic bacteria.
Oral hygiene practices must start soon after birth and counseling in this area should involve both parent and patient. The infant’s gums can be cleaned daily using a moist, soft cloth prior to tooth eruption. Once the teeth erupt, oral hygiene must be practiced in earnest, particularly in high-risk children. Due to a lack of manual dexterity in children younger than 8 years of age, parents need to brush for them twice daily and assist with flossing if their child’s teeth are tightly contacting each other.
Fluorides are safe and effective in caries prevention through three topical and systemic mechanisms of action. By both routes of administration fluorides can affect the dentin and enamel of erupted and unerupted teeth. Topical application inhibits bacterial metabolism by interfering with enzyme activity; inhibiting demineralization; and enhancing remineralization.
Systemic benefits are achieved by oral ingestion from sources such as fluoridated drinking water, beverages, infant formulas, and prepared food. Recently, the US Department of Health and Human Services proposed a lower limit of 0.7 ppm for fluoride levels in community water supplies to balance the benefits of preventing dental caries while minimizing the risk for enamel fluorosis. Since fluorosis is associated with cumulative fluoride intake during enamel development, the severity of the condition is dependent on the dose, duration, and timing of the oral intake of fluoride containing products. Infants who consume concentrated infant formula as the main source of nutrition are at an increased risk for enamel fluorosis in the permanent dentition if fluoride-containing formulas are reconstituted with fluoridated drinking water.
Fluoride supplements also help reduce dental caries prevalence and are a consideration for children at high caries risk who drink fluoride-deficient (< 0.6 ppm fluoride ion) water. Factors associated with a high caries risk include orthodontic appliances, decreased salivary function, gastroesophageal reflux disease, a cariogenic diet, physical inability to properly clean the teeth, mother or siblings with caries, and personal history of caries. However, as recommended by the American Dental Association, a child’s true exposure to all sources of fluoride must be thoroughly evaluated before supplements are prescribed so as to avoid enamel fluorosis.
The judicious use of fluoride-containing toothpastes and mouth rinses for children reduces dental caries prevalence in the primary and permanent dentition. Since children younger than 6 years of age cannot expectorate reliably and lack appropriate dexterity for proper brushing, parents must monitor the use of fluoridated toothpaste at each brushing, ensuring that only a “smear layer” (< age 3) or “pea-sized” amount (3–6 years of age) of dentifrice is used to reduce the risk for fluorosis. The beneficial effect of fluoride containing toothpaste can be maximized by brushing teeth twice daily and either avoiding or rinsing minimally after brushing.
Fluoride Varnish for High-Risk Populations
Applications of fluoride varnish during well-child visits with physicians is successful in reducing dental caries among vulnerable children (ICD-10-CM Diagnosis Code Z29.3: Encounter for Prophylactic Fluoride Administration). The sticky nature of the varnish’s resin base allows for extended contact time of its fluoride content with the tooth surface.
The varnish in single-dose packages (0.3–0.5 mL) should be stirred before application and the contents of larger tubes (5 mL) massaged to dissolve any precipitated fluoride. The former are preferable because consistent availability of fluoride cannot be guaranteed with multi-dose packages. The average amount of varnish needed depends on the number of teeth present and ranges from 0.1 mL for infants to 0.3 mL for preschool children. Teeth should be dried with gauze before the varnish is applied with a small brush. It will set quickly to a dull yellow film upon contact with saliva. Caregivers should be instructed not to brush or floss and to give their children only soft foods until the next morning to provide enough time for absorption of the fluoride into enamel.
Other Adjunctive Measures
Xylitol containing products are marketed in many forms (eg, gums, mints, lollipops, chewable tablets, toothpastes, mouthwashes) as an adjunctive measure in caries prevention. Xylitol is considered a noncariogenic substitute due to the inability of oral bacteria to metabolize this five-carbon sugar alcohol. However, recent systematic reviews suggest that there is limited evidence for caries reduction from xylitol-containing products.
Caries is usually diagnosed by visual and tactile oral examination supplemented by radiographs to detect caries on the surfaces between teeth. The initial defect observed on enamel beneath dental plaque is the so-called “white-spot lesion,” a white, chalky, decalcified area along the gingival margin or on approximated tooth surfaces. Frank carious lesions are light- to dark-brown spots or cavities of varying size on the tooth. A light shade of brown indicates rampant decay, while arrested caries is almost black in color.
In the early stages of decay, the tooth may be sensitive to temperature changes or sweets. Removing the carious tooth structure and filling the early defect with a restorative material can repair the tooth. As decay progresses deeper into the pulp, inflammation and pain increase. Eventually, the entire pulp becomes necrotic, and a choice must be made between root canal therapy (pulpectomy) and removal of the tooth. In the presence of cellulitis, extraction, and antibiotic therapy are the treatments of choice.
When restorative materials are used to repair a tooth, the primary choices include dental amalgam, composite resin, or glass ionomer cement. For primary molars with extensive caries and/or pulpal involvement, full coverage crowns are the restorations of choice and these are available as preformed stainless steel crowns and in various cosmetic iterations.
Silver diamine fluoride has been utilized to slow or arrest caries progression in select patients. Its use may be considered in circumstances where the risk of morbidity or mortality under sedation or general anesthesia outweighs the benefit of definitive restorations. Once applied, the medicament produces a gray-black discoloration of carious defects of treated teeth and may be interpreted as caries.
American Academy of Pediatric Dentistry. Policy on early childhood caries (ECC): classifications, consequences, and preventive strategies. Pediatr Dent 2016;38 (special issue):52–54.
American Academy of Pediatric Dentistry. Policy on early childhood caries (ECC): unique challenges and treatment Options. Pediatr Dent 2016;38 (special issue):55–56.
RG: Office-based preventive dental program and statewide trends in dental caries. Pediatrics 2014 Apr;133(4):e827–e834
WF Jr: The use of fluoride
varnish in children: a critical review with treatment recommendations. J Clin Pediatr Dent 2008;32(4):259–264