Dental Caries: Preventing the #1 Childhood Disease

Preventing the
#1 Childhood Disease

Dental caries is the number-one childhood disease, affecting 30% of two- to five-year-olds and 49% of six- to 11-year-olds. The numbers continue to increase with age as 50% of 12- to 15-year-olds experience dental caries, 68% of 16- to 19-year-olds, 87% of 20- to 39-year-olds, 95% of 40- to 59-year-olds and 93% of those 60 or older.

According to the U.S. government, it is estimated that children lose 52 million hours of school each year due to dental visits and oral health problems. Adults lost 164 million hours of work in 1989 due to dental visits or oral health problems.

For decades, dentistry has focused on repairing the damage done by the caries process, often needing to retreat teeth due to recurrent caries or breakage of the original restoration. Researchers continue to search for better and longer lasting restorative materials. Until recently, the focus has been on repair, as dental caries seemed inevitable. Today, our understanding of the caries process has led to early interventions that reverse the demineralization of enamel and repair the tooth before the first break in the enamel. Instead of waiting until a tooth surface decays to initiate treatment, your task is to keep enamel surfaces strong and resistant to the acid assault of caries bacteria.

The Caries Process

In the 1700s, “tooth worms” were believed to cause tooth decay beginning on the inside of the tooth and working their way out. Today we know that tooth decay is a contagious, bacterial infection that begins with demineralization of the enamel, just below the surface. Acid from several sources penetrates the enamel and causes demineralization. Reversal of demineralization is possible until there is a break or cavitation in the enamel surface, allowing acid access to deeper areas and protection from routine daily cleaning and salivary neutralization.

The primary acid source is from Streptococus mutans consuming refined carbohydrates and releasing lactic acid. Carbonated beverages, fruit juices and sports drinks are also sources of acid. Enamel will demineralize when the pH drops below 5.5, and many carbonated drinks have a pH as low as 2.8. Low pH drinks will soften enamel, thus speeding up the demineralization process caused by oral bacteria. Low pH beverages containing sugar not only soften enamel, but also provide a carbohydrate source for oral bacteria, thus leading to even more acid and enamel demineralization.

The introduction of water fluoridation in the 1950s reduced the incidence of tooth decay, but more recent changes in the American diet are increasing the caries rate. Significant changes include the increase in carbonated beverages, high carbohydrate snacking rather than the regular three meals per day, and high carbohydrate fast food. According to the Center for Science in the Public Interest, companies produce enough soda pop each year to provide 557 12- oz. cans to every man, woman and child in the country; sugar consumption has increased 28% since 1983; and the average teenage boy consumes 34 teaspoons of sugar each day.

The first surface of decay begins a lifelong progression of breakdown. Prevention of the first surface cavitation will stop the entire process. Failing to prevent demineralization can set the tooth up for a lifetime of disease and expensive, painful repair. A single surface of decay, treated with a restoration is at greater risk of future caries than a healthy surface. To bacteria, the margin between a restoration and the tooth is the size of the Grand Canyon. Bacteria populate the margins, produce acids and continue the demineralization process, leading to more cavitation and the need for larger restorations or more complex dental treatment. Treated surfaces are at increased risk of further caries activitiy. Dr. Nigel Pitts from the University of Dundee in Scotland has captured the destructive cycle of dental caries in his “Restorative Cycle.” Prevention of this cycle of destruction is the dental hygienists’ goal.

Caries Detection

Detecting demineralization at an early stage will allow for remineralization treatments and prevention of cavitation. Early detection is our goal. However, the complexity of anatomy on the occlusal surfaces of teeth complicates visual and explorer detection. In the past, our attention was focused on looking for decayed surfaces rather than early demineralization. It is only in recent years that remineralization of enamel was demonstrated and thus changed our focus.

Radiographs show lesions only after they have progressed at least 30% into the enamel. A sharp explorer was the primary tool for caries dectection in the past, but no more. The sharp explorer is now considered obsolete and harmful rather than helpful, as it can break through softened, demineralized enamel, causing cavitation and eliminating the option of remineralization. Even narrow diameter explorers cannot reach to the base of deep grooves or pits to detect decay. Air, light and magnification are still helpful for evaluating enamel surfaces and several diagnostic and imaging systems are also available.

DIAGNOdent and the DIAGNOdent pen from KaVo use laser technology for detecting occlusal caries. A baseline reading is taken from each patient just prior to evaluating surfaces for decay. Both an audible signal and digital number measure laser-reflected light. Quantified laser-reflected light can be used to detect a carious lesion. The DIAGNOdent quantifies the lesion based on the following reading:

    0-10 = Healthy
    10-20 = Early caries in the outer enamel
    20-30 = Caries extending into the inner enamel
    30+ = Dentinal caries

The Inspektor Pro from OMNII is a pre-invasive caries diagnostic imaging system that uses quantitative light-induced fluorescence (QLF). When teeth are illuminated with a specific wavelength of light they appear to be lit from within and the fluorescence level reflects the mineral content of the enamel. This increases the contrast between sound and diseased enamel, thus defining surface mineralization, plaque biofilm, calculus, and staining. The mapping and analysis software allow for capture of the images and comparison at future visits. This tool will provide data on early enamel changes, thus allowing for remineralziation options.

D-Carie and the D-Carie Mini from Neks in Canada use fiberoptic technology and light-emitting diode (LED) lights for detection of occlusal and interproximal lesions. Both audible and visual signals are given. Green is healthy and red is carious. It is available in both a desktop and handheld models and no baseline calibration is required.

Digital Imaging Fiber Optic Trans-illumination (DIFOTI) uses white light to trans-illuminate the teeth and then capture a high-resolution digital image of an occlusal, interproximal or smooth tooth surface. A single surface can be imaged in three seconds, or the entire mouth in just a few minutes. The images look similar to radiographs, without the use of radiation. According to research published in Caries Research, 1997, DIFOTI images can indicate the presence of early decay before either film or digital radiography. This technology was recently licensed to the KaVo company to take over U.S. distribution and future product development.

Demin/Remin Process

The hardness of tooth enamel in the mouth is in a constant state of flux. Acids in foods and beverages will demineralize the enamel while minerals in the saliva will remineralize the surface. Polishing pastes will remove minerals from the surface, while fluoride and saliva will replace lost minerals. The demin/remin process can be influenced by reducing acid and refined carbohydrate intake and by using products that provide remineralization and products that alter Streptococus mutans and stimulate salivary flow.

Basic oral hygiene and saliva are the most important approaches for preventing demineralization and promoting remineralization. Brushing and cleaning between the teeth will disrupt the bacterial biofilm, and minerals in the saliva (calcium, phosphate and fluoride) will promote remineralization.

Reducing refined carbohydrate and carbonated beverage intake will reduce the food source for Streptococus mutans and reduce the potential acid assault on the teeth. Nutritional counseling is an essential part of caries prevention.

According to the research, toothbrushing should be avoided after ingesting high-acid foods and drink as the bristles and the toothpaste will erode the softened enamel. This means avoid brushing after morning orange juice. It is better to brush before drinking orange juice, to remove the plaque bacteria before ingesting a high acid orange juice.

Several products are available to promote remineralization: fluoride, amorphous calcium phosphate (ACP), and xylitol. Fluoride varnish has been used for several decades in Europe and has received FDA approval in the U.S. as a desensitizing agent, but not for caries control. However, a recent publication by the ADA reviewed all previously published fluoride research and recommends fluoride varnish for caries prevention. According to the ADA publication: “Fluoride varnish applications take less time, create less patient discomfort, and achieve greater patient acceptability than does fluoride gel, especially in preschool-aged children.”

According to the ADA publication, fluoride gel and foam treatments of four minutes were reported effective for caries prevention. However, no clinical research is available to support one-minute fluoride treatments. To be effective, professional fluoride treatments with gels and foams must be four minutes, according to the research. If time is the concern, fluoride varnish should be the choice rather than cutting a four-minute fluoride treatment to one minute and not achieving optimum results.

Several companies offer products for home use to enhance remineralization. Pastes containing 5,000 ppm fluoride are available from Colgate PreviDent 5000, Oral-B NeutraCare Home Topical, Omni Control RX. ACP (amorphous calcium phosphate) paste is available from GC America as MI (minimally invasive) Paste. The calcium phosphate in MI Paste enhances remineralization.

A novel approach to remineralization and bacterial control is xylitol sweetener. Xylitol sugar occurs naturally in berries, fruits, vegetables, mushrooms and the bark of birch trees. It is a five-carbon sugar, compared to six-carbon sugars such as sorbitol, fructose and glucose. This difference makes it difficult for bacteria to metabolize xylitol, thus preventing caries. Xylitol is sweeter than some sugars and as sweet as sucrose, but with 40% fewer calories. The use of xylitol chewing gum will increase saliva, thus increasing minerals available to remineralize enamel.

Xylitol was discovered in 1890 in Europe and in 1943 was found in plants. In the early 1960s it was shown to be an effective IV drip for seriously ill patients. In 1963, the U.S. Food and Drug Administration approved the use of xylitol for special dietary purposes. In 1970, the dental importance of xylitol was discovered in Finland and many research studies followed, demonstrating the caries preventive effect of xylitol.

Xylitol is now available in chewing gum, lozenges and in raw form to use in place of sucrose at home. Besides the caries preventive effects, xylitol chewing gum has also been shown to prevent ear infections.

Many companies now offer xylitol chewing gums (Spiffies, Spry, Xlear, OMNII TheraGum, Carefree Koolerz,), lozenges, (Starbucks, OMNII TheraMints), toothpastes (Squiggle), and mouth sprays (Omnii TheraSpray).

Future

Dr. Jeffrey Hillman is the name to watch for future innovations in caries prevention. Dr. Hillman has worked for nearly 30 years developing a strain of Streptococus mutans that does not produce acid and therefore does not cause tooth decay. The challenge is replacing the current strain with the new strain. That will be easy, as the new genetically modified strain produces an antibiotic specific for the current Streptococus mutans strain. Swishing with a new mouthrinse will introduce the new strain of Streptococus mutans into the mouth. According to Dr. Hillman, this treatment will take place in the dental office, probably cost less than $100 and may last a lifetime. Dr. Hillman cautions that good oral hygiene will still be needed to prevent periodontal disease and bad breath. Human research trials are now underway and if all goes as anticipated, this new replacement therapy will be available in the near future.

Dr. Hillman’s replacement therapy findings may be even more important to the study of antibiotics. Rather than using antibiotics, a genetically altered harmless bacteria may be introduced that will eliminate the harmful bacteria without the risk of developing antibiotic resistant stains of bacteria, a significant and growing problem today. This antibiotic is a member of a new class of molecules called Lantibiotics. Sensitive bacteria do not seem to be able to gain resistance to Lantibiotics. Dr. Hillman’s research team has exposed trillions of sensitive cell strains without finding any genetically stable resistant mutants. Researchers do not yet know why this is, but it is a significant finding.

On the horizon is an approach to caries that is actually quite old and based on eastern medicine. Biologic dentists and dental hygienists look at dental caries with an eye to the relationship of teeth to organs in the body. According to Dr. Dawn Ewing, a dental hygienist, naturopathic physician and author of Let the Tooth Be Known… Are Your Teeth Making You Sick?, the study of energy fields within the body suggests a connection between the teeth and specific organs. If an organ is in dysfunction, this could increase the likelihood of the corresponding tooth to be more susceptible to decay or infection. It works the other way as well. Teeth that are decayed or infected may alter the health of the organs on that same energy meridian. The field of biologic dental hygiene is growing and with that will come more research evaluating not only dental caries as we know it, but how energy fields connect the teeth and other parts of the body.

Dental caries remains a huge problem, despite years of advancing prevention. Early interception will allow for remineralization therapy with many products and approaches. The value of nutritional counseling has never been more important. The goal of dental hygienists is to prevent dentistry that is needed because of dental decay. By providing oral hygiene instructions, nutritional counseling, monitoring of enamel mineralization and remineralization therapies you will provide people the opportunity to live caries free. n

Editor’s Note: Some information used in this article is from the Hygienetown.com online continuing education course “The New Approach to Caries Diagnosis and Treatment” by Dr. Lori Trost. To view this course at no charge, please visit www.hygienetown.com, click on “ONLINE CE” and select Dr. Trost’s course.

A variety of risk factors have been identified. This is a compilation of several risk assessment tools.

Low Risk No carious lesions No demineralization No restorations Shallow pits and fissures Adequate fluoride Adequate salivary flow Low sugar diet Low acid intake No between meal snacks Good oral hygiene Low Strep mutan levels Regular dental visits Good family economics

Moderate Risk One carious lesion One demineralized site One restoration Deep pits and fissures Inadequate fluoride Reduced salivary flow Moderate sugar diet Moderate acid intake Occasional between meal snacks Moderate oral hygiene Orthodontic appliances Elevated Strep mutan levels Irregular dental visits Moderate family economics Identification of special needs

High Risk Two or more carious lesions Two or more demineralized sites Two or more restorations Deep pits and fissures Inadequate fluoride Reduced salivary flow High sugar diet High acid intake Frequent between meal snacks Poor oral hygiene Orthodontic appliances Elevated Strep mutan levels Irregular dental visits Poor family economics Identification of special needs