Under Construction: The State of Dental Caries
Allison M. DiMatteo, BA, MPS
The oral healthcare profession now has a more substantive database of evidence-based, scientific studies that have provided a realistic interpretation and understanding of the caries process than it did 25, 15, or 5 years ago. However, despite knowledge that the use of fluoride, sealants, and other measures can prevent caries, the Centers for Disease Control and Prevention report that many adults have untreated dental caries (eg, 27% of those 35 to 44 years old and 30% of those 65 years and older). Further, dental caries remains the most common chronic disease of children aged 5 to 17 years—5 times more common than asthma (59% versus 11%).1
“Today, we look at caries, the disease process, and its symptoms very differently than the classical view because we know it relates to the biofilm and what goes on with the biofilm,” explains Howard E. Strassler, DMD, professor and director of operative dentistry in the department of endodontics, prosthodontics, and operative dentistry at the University of Maryland Dental School. “The biofilm refers to what is coating the teeth, and it’s based upon saliva, plaque, what’s ingested, fluorides, calcium phosphates, and beverages. Those really impact the enamel and root surfaces and their susceptibility to caries.”
According to V. Kim Kutsch, DMD, a private practitioner and lecturer from Albany, Oregon, while it was once thought that sugar caused the selection for the harmful bacteria that led to decay, it’s now understood that it’s the low acidic pH generated by the biofilm on the teeth. The professional also knows that there have been at least 24 different bacteria implicated by different researchers worldwide in the last 10 years or so as playing a role in this biofilm disease, Kutsch says. This is quite a development from what dentistry believed years ago.
“If we look at dental caries and our policy on dental caries over the past 25 years, we primarily were considering it a disease of Streptococci mutans and Lactobacillus. We had a lot of studies in the 1980s that correlated those two bacteria to a higher incidence of decay, particularly in children,” recalls Kutsch. “In 1989, Philip Marsh in the United Kingdom did a series of studies in which he proved that caries was more of a biofilm disease, not necessarily a function of those two specific pathogens, but a function of the pH.”
As a result of what we know today, how caries and their symptoms are handled is vastly different than how they were handled previously. From looking at the risk factors that a patient has—whether behavioral (eg, diet or homecare) or in terms of the medications they take that cause xerostomia and insufficient saliva—to using fluoride and remineralization techniques, activities in dentistry now attempt to reduce a patient’s overall bacterial load and limit the re-restoration cycle.
This month’s feature provides a review of what’s understood today about caries detection, disease diagnosis, caries prevention, and tooth remineralization and treatment and what it means to clinicians for day-to-day practice. Additionally, our interviewees address the challenges that still remain despite the many advancements that have taken place in terms of arresting the caries process. They also comment on those areas of patient education and behavioral modification that still require attention. Some of the available caries detection and assessment technologies and how they are applied in clinical practice also are reviewed.
Admittedly, this cover presentation is a quick update and review. For more in-depth reading on some of the science, technologies, and techniques discussed, we encourage you to consult the literature, as well as back issues of Inside Dentistry and our sister publication—The Compendium.2,3,4,5,6
Caries as a Biological & Behavioral Disease
Caries now is understood to be a biological disease, one that can be managed from the medical perspective versus only a surgical or restorative process. “This is a big shift from the old school, particularly in the early 1900s when we first established the bacterial cause of the disease but didn’t really address intervention and methods to intercept the process bacteriologically and antimicrobially,” observes Paul J. Vankevich, DMD, assistant professor of oral diagnosis/oral medicine at Tufts University School of Dental Medicine.
Peter Arsenault, DMD, MS, head of the operative division of the department of prosthodontics and operative dentistry at Tufts University School of Dental Medicine, agrees. He explains that, years ago, dentists would see the disease or decay and they typically would surgically remove the disease, then restore the tooth by filling it.
“What dentistry is heading toward is the medical model, which is to identify the cause of the disease and eliminate the cause, which is bacteria; and we’re doing that through bacterial cultures,” Arsenault says. “Once we identify bacteria levels, according to the medical model, if the patient has dry mouth, we address that medical issue first, or we try to control decay by antibacterials or by increasing salivary flow to neutralize the pH.”
But Joel H. Berg, DDS, MS, professor and chair of the department of pediatric dentistry at the University of Washington School of Dentistry, elaborates further on the behavioral aspect of the disease. He says that it’s the behavior of how sugar is consumed, how often individuals brush their teeth, and if they engage in proper fluoride regimens that collectively impact preventing disease.
“Caries is a biological disease, of course, but whether you have it or not is behavioral,” Berg says. “Therefore, that means we need to engage people from a variety of disciplines who have expertise beyond what we have in dentistry in order to change behavior and get people to bring their children in for the age-one dental visit. Ultimately, it’s all about behavioral change.”
Assessing Caries Risk
The concept of caries risk management today recognizes that a person’s risk of developing caries—and therefore prevention and treatment—must be determined on an individual basis. Vankevich explains that it’s a common-sense method of applied, preventive dentistry to intercept the process and prevent the progression of caries disease. In its simplest terms, caries risk management involves looking at the individual etiology and causation of dental caries; examining the individual patient’s bacterial load; reducing the patient’s susceptibility by using fluorides and remineralizing agents; and exploring the patient’s initiative for mechanical oral hygiene (ie, brushing, flossing).
“Caries risk assessment is becoming a standard of care and the technologies—remineralization technologies, antimicrobial technologies, measurement of bacteria levels—are becoming available to professionals,” Arsenault emphasizes. “What’s really going to push this is the legal system, in many ways.”
For example, if a patient comes into a dental practice and has a mouthful of decay and a dentist only restores everything but doesn’t look at the risk level of the patient (ie, medical aspects, medicines that cause dry mouth, bacterial levels) or doesn’t prescribe antimicrobials, remineralization paste, fluorides, or Xylitol, the patient may return a year later with more decay. At that time, the dentist may be liable, Arsenault suggests.
Strassler elaborates that when thinking of the caries process, each patient should be viewed individually. The process is very different for children than it might be for a young adult, someone in their 30s or 40s, or, considering that people are keeping their teeth longer, patients who are older, he says.
“The caries risk with the elderly involves the impact of recession and exposed root surfaces, and you’ll observe differences in root caries versus enamel caries, as well as differences between susceptibility of the tops of the teeth, the pits and fissures, versus the smooth surfaces on the facial, lingual, and interproximal surfaces,” Strassler explains.
An individual in their 40s who has never had any experience with tooth decay would be considered at low risk for caries, compared to a child who has erupting teeth for whom examination of the tops of the teeth, pits and fissures, and occlusal surfaces is important. Clinicians would want to keep them at low risk by placing sealants, Strassler suggests.
Regularly assessing risk is important on a regular basis for both adults and children, Kutsch says. He explains that individuals could be decay-free for a period of 20 or 25 years as an adult, and then some of their risk factors may change (eg, diet or medications), leaving them with new cavities.
“What we know today is that it isn’t about just throwing a toothbrush and toothpaste at the tooth and placing restorations, but about really understanding each individual for what creates risk for them,” Strassler emphasizes. “If they are at risk, then it’s about modifying our treatment and our plan based upon that individual risk.”
Awareness of Who’s Vulnerable for Caries
Interestingly, and unfortunately, the dental patient population at risk for caries may have shifted. In the United States, the reality today is that 80% of dental caries is found in only 20% of the patient population, explains Vankevich. What’s more, certain patient populations are at increased risk because of socioeconomic challenge and limited access to care with respect to preventive dentistry and treatment, he says.
“We also have an increased population of older individuals who are retaining their teeth much longer, and they may have experienced periodontal disease with recession of supporting tissues and exposed root surfaces that are then increasing their risk for root decay,” Vankevich says. “So, we’ve had a shift in the population who may be at risk.”
Additionally, Strassler notes that older patients are likely to have had extensive restorative dentistry throughout the course of their lives, extensive crowns, fixed prosthodontic procedures, bridges, and partial dentures that may be susceptible to decay. What’s more, these individuals may be at the highest risk for caries because they may experience changes in their saliva flow from medications that decrease saliva flow and limit saliva’s cavity-preventing benefits, he says.
“Dentists need to understand their patients’ individual situations, base their assessments on all factors, and not wait until they start to see the decay to make prevention and intervention decisions,” Strassler cautions. “Also, it’s important to recognize a patient’s ability for oral home care, and that they may have changes in hand skills due to arthritis, resulting in a limited ability to use a brush or floss.”
Remineralization & Minimal Intervention
Today, dentistry is incorporating remineralization techniques through which a carious lesion is aborted, reversed, or otherwise stopped if it is diagnosed at an early stage, thereby preventing the need for surgical or restorative intervention. “The emphasis here is early diagnosis, patient assessment, and then utilization of processes, techniques, and chemotherapeutic methods for remineralization,” Vankevich says. “The goal is to preserve as much tooth structure as possible and not remove and replace tooth structure with restorative materials, which may have limited longevity and eventually will require replacement.”
According to Arsenault, clinicians now can remineralize caries that they traditionally would treat, an advancement that’s going to play a huge role in how patients are treated from now on. “We’re going to be looking at chemotherapeutic agents—the fluorides, varnishes, remineralization pastes, Xylitol, antimicrobials—to remineralize the demineralization that has occurred,” Arsenault explains. “That’s where dentistry is at this time, and moving into the future, there are products that are being developed such as probiotics and anticaries agents that will be very selective to the specific bacteria that cause dental caries.”
Challenges Still Remain
Despite all its advancements, when it comes to caries, the dental profession continues to face several challenges.
According to Strassler, the biggest challenge facing the profession is the fact that dentists don’t take caries risk assessment seriously. Additionally, dental insurance doesn’t adequately reimburse clinicians for the prevention of disease.
“We don’t have healthcare. We have sick care. You get rewarded when the patient has disease—when you’re filling holes in the teeth, replacing missing teeth, or restoring tooth structure,” Strassler says. “There is nowhere that the insurance companies recognize the value and need to conduct testing to assess a patient’s caries risk and then provide an individualized treatment plan.”
Strassler does point out that there are now new ADA codes allowing dentists to code for saliva testing (ie, saliva flow, salivary acidity) when diagnostic tests are performed. He says this is not to say that the insurance companies will pay for it, but at least there is a way of noting it.
Amod A. Kher, North American product manager for KaVo Dental, shares similar feelings, noting that the early detection of dental caries is the key challenge in the management of dental caries and its prevention. He says that studies have shown that the past state or presence of caries is a great predictor of future caries; today’s non-invasive methods can assist clinicians in detecting and quantifying early carious lesions, as well as assessing the state of the lesion.
Of concern to Berg is the fact that caries continues to be on the rise in certain populations, such as preschoolers. Kutsch says that the decay rate is increasing in children, particularly those in the less than 1-year to 5-year-old age bracket. Despite the use of higher and higher levels of fluoride, he says that the decay rate is increasing dramatically.
The challenge is, therefore, to get these children in for dental visits early in their lives (eg, by their first birthday), and to get families to understand the importance of this infectious disease and its danger to children and their oral health, Berg says.
“If the dental experience starts with a cavity, the whole perspective of dentistry is one of disease as opposed to one of health; one of pain as opposed to no pain,” Berg says. “So, our biggest challenge, I think, is to educate the consumer, or the parent in the case of a young child, about the importance of early intervention, early prevention, and assessing your risk early so that even if you have a high risk, we can mitigate it and keep you disease-free.”
However, others see the biggest challenges involving caries centering around what’s been taught in dental school about caries and the proverbial, yet outdated, “gold standard” of caries detection on the occlusal surfaces. The gold standard was a probe and an x-ray, says Jon Newman, digital imaging product specialist for Air Techniques. The problem with this method is that it’s very difficult to detect early caries in an x-ray with a radiograph, and by the time it’s seen on an x-ray radiographically, usually 20% to 30% of the enamel has been eroded away. When a probe is used, if the pit and fissures went down deep, the probe may not be able to hit problematic areas in which decay had developed, Newman says.
According to Carri Cady, RDH, vice president of sales and marketing for Oral Biotech, the way dentists are taught within the school system poses a challenge to modern-day prevention and treatment. For example, she notes that they spend little time understanding that dental caries is a bacterial infection, after which restorative techniques are taught. They learn how to treat the signs and symptoms, but essentially skip the whole concept of treating the bacterial infection, she suggests.
“I think anyone’s standpoint, whether they are a manufacturer or a clinician, is that it’s important to detect early stages of caries,” believes Newman. “In doing so, you’ll be able to promote minimally invasive treatments that conserve tooth structure and allow the body to repair and regenerate itself on its own.”
Wong echoes those sentiments, adding that for clinicians—hygienists as well dentists—modern-day approaches to caries intervention and disease management are about being noninvasive and conservative. That’s why the technologies discussed here (see Applying Technology to the Caries Conundrum) would be tremendously beneficial to dentistry, she says.
“Whatever we do should always be in the best interest of our patients, and if we engage in caries treatment that may remove irreplaceable tooth structure, our diagnosis must be accurate so that we can always be conservative to the best of our ability,” Vankevich emphasizes.
Unfortunately, the fact remains that dentistry in the United States is a $90 billion-a-year business, with about 60% of that being spent on treating the effects of dental caries, Berg says.7 That could encompass most restorative dentistry, endodontics, prosthodontics, and some oral surgery.
“We’re spending over $50 billion a year treating the latest form of the most common disease, dental caries,” Berg emphasizes. “Because of the historical absence of technology to detect the caries process at early stages, we’ve been compelled to treat the lesions when the tooth becomes cavitated, in the surgical phase. Now we’re entering into a world where we’re going to be managing caries in the preventive phase, including the management of caries lesions that are detected early prior to cavitation.”
That said, Arsenault believes that caries risk assessment is the foundation of good, evidence-based dentistry, and that it’s the future of dentistry. It’s what’s going to drive all dentistry, he says, and it’s what will allow dentists to treat patients more predictably by lowering their risk levels and delivering better quality dentistry through treatment of the patient as a whole, more so than just tooth by tooth.
The inside look from...
Issue after issue, the feature presentations in Inside Dentistry deliver coverage of relevant topics specifically affecting the dental profession, as well as oral healthcare in general. The publishers and staff could not bring the underlying concerns surrounding these timely issues to the forefront without the insights shared by our knowledgeable and well-respected interviewees. For their collective generosity of time and perspectives, we extend our sincere gratitude.
Peter Arsenault, DMD, MS
Joel H. Berg, DDS, MS
Carri Cady, RDH
Amod A. Kher
V. Kim Kutsch, DMD
Howard E. Strassler, DMD
Paul J. Vankevich, DMD
Sue S. Wong
Focusing On Individualized Prevention and Management Strategies
To this end, there are a number of preventive technologies that—if early-stage caries are recognized—allow clinicians to increase the resilience of tooth structure to the process of dental caries. For example, in addition to fluoride remineralization, other chemical agents enable dentists to reverse demineralization at the early stage of caries, Vankevich explains.
Arsenault explains that the regimen prescribed for an individual patient would be based on the risk level, and there are certain protocols to be followed for each of the four levels—low, moderate, high, and extremely high risk. For example, somebody who is at high risk for caries, initially will have more frequent recalls, salivary tests, and bacterial tests. Then, the treatment regimen would include antibacterials and fluorides, including varnishes. There likely would be an increased frequency of radiographs and oral exams.
“We’ll be looking at Xylitol. We’ll be looking at incorporating baking soda to neutralize pH and, of course, sealants and caries control,” says Peter Arsenault, DMD, MS. “These are some of the treatments we definitely have available and use.”
Berg says that clearly dentistry has at its disposal many tools for prevention, and the profession knows fairly well that most caries in young children and in adults is preventable. It’s a question of just how much effort is required to prevent it. Customized preventive efforts could include—but certainly aren’t limited to—the use of the following:
Mechanical plaque removal (ie, toothbrush, toothpaste). To effectively clean the teeth, we need several minutes going surface by surface. The introduction of mechanical toothbrushes changed the way we look at cleaning the teeth. While they were previously very expensive, in recent years their accessibility has increased for everyone, says Strassler.
Fluoride delivery For children and adolescents, fluoride (eg, gel, tray systems) is delivered every 6 months, at which time the teeth are immersed in the high concentrations of the protective agent. “I think the most prevalent preventive measure is actually fluoride varnish, and they are becoming more and more prevalent in the United States,” says Berg. “They’ve made our life easier in terms of the ease of application of fluoride, especially for young children. They provide twice the concentration of sodium fluoride as a gel, and you get much less volume, so the safety factor is much greater with fluoride varnish.”
Remineralizing compounds (amorphous calcium phosphate). Prescription-strength fluoride dentifrices, in combination with at-home products, are helping to remineralize teeth, strengthen the enamel, and make teeth more resistant to the bacterial plaque and acid attack, Strassler says. Work also is underway to develop other remineralization compounds, such as amorphous calcium phosphate, that can smooth over an acid-roughened tooth with only a surface application of these calcium phosphates. “It used to be that these were only dispensed by a dentist, but we’re seeing calcium phosphate-containing toothpastes entering the market that are resurfacing of the enamel,” Strassler says.
“Our new approach to caries management from a preventive standpoint is that everybody needs an individualized preventive regimen. Twenty years ago, everybody received a 6-month recall, regardless of their particular risk; everybody was treated the same,” recalls Joel H. Berg, DDS, MS. “Like our colleagues in medicine, we need to do a risk assessment to determine where the risk focal points are for an individual patient and what we need to do for them, as an individual, to mitigate their risk of getting disease. Some patients may need to be seen as often as every 2 months. Every individual needs a customized prevention plan. That’s the focus of today’s dentistry.”
Of paramount importance to the individualized approach to prevention and, perhaps, ultimate treatment is an understanding of the patient’s risk factors. As described earlier, these inherently include identifying the kind of bacteria in their biofilm, says V. Kim Kutsch. In the medical management model, dentists focus on the microbiology of the mouth and correct it so that, if successful, patients should stop getting carious lesions, he explains.
“If we can get a child through their adolescence without decay, there’s a good chance that they will be decay-free for their entire life,” Kutsch says. “However, if they start with this disease early, they’re going to get into the restoration and re-restoration cycle, which will put them back in the dental chair for the rest of their life.”
Applying Technology to the Caries Conundrum
The old method of assessing the presence or absence of caries by visual clinical examination using an explorer and radiography—although it could be effective—in most cases identified late-stage carious lesions, explains Paul J. Vankevich, DMD. The emphasis today is for early-stage diagnosis of disease and/or detection of symptoms.
“If one were to choose the area where we have the greatest difficulty diagnosing, it would be pit-and-fissure caries,” says Howard E. Strassler, DMD. “According to the classical explorer method, the dentist would make diagnoses based upon a physical phenomenon rather than a disease phenomenon.The introduction of digital technologies allows us to get a better sense of the changes to the surface of the enamel, the changes in the translucency of the enamel, and whether the demineralization process is occurring.”
“The important thing about all of these technologies, regardless of what gets developed and makes it into the marketplace, is that they’re going to breed a whole new array of therapeutics to treat the caries lesions,” asserts Joel H. Berg, DDS, MS.
These include—but are not limited to—the following (listed in alphabetical order):
Midwest Caries I.D.
“The technology bounces back an audible as well as a digital signal to the clinician,” Wong explains. “So, an absence of the bright red light would indicate that the tooth is a healthy structure. If it was a red light, then it would indicate a stage of decay.”
“The CariScreen is used ideally as a screening tool for all patients, whether they’re experiencing decay today or not,” Cady says. “The real strength of the technology is its ability to screen every patient and identify shifts in their bacterial load away from the healthy strains toward the more acid-producing strains so the condition can be treated preventively before the cavitations start to form.”
ATP Bioluminescence is not a new technology and has been used for years in the healthcare and food industries to identify the presence of bacterial load on surfaces. The application of ATP Bioluminescence technology to dentistry, however, allows clinicians to make a real-time assessment of health versus disease state, Cady explains.
“Fluorescence can be used for caries detection because of the difference in fluorescence observed between sound and demineralized enamel, which is greater when the enamel is illuminated by light,” Kher explains. “The DIAGNOdent uses infrared light and has a 655 nanometer wavelength.”
DIAGNOdent, which was introduced in the United States in 2000, is based on the principle that a tooth surface fluoresces when irradiated by a light of a given wavelength. This fluorescence changes according to the optical characteristics of tooth tissue associated with bacteria, Kher says. The value of this change may, therefore, give an indication of the extent of the disease process.8,9
According to Berg, DIFOTI is an intense transillumination device. In terms of primary teeth, based on his studies, once the technology is perfected, it might, in some instances, be an alternate to bitewing radiography. An intense light could be shined interproximally, perhaps eliminating the need for radiographs. “We’re not there yet, but I think the growth of that technology could get us there at some point,” Berg speculates.
Inspektor Pro System
“QLF devices can somewhat predict when a cavity might happen,” Berg says. “The problem with many of the very sensitive devices is that we don’t know which lesions will progress and which ones will remineralize on their own by virtue of preventive regimens.”
The device is connected to a computer, enabling the clinician to use imaging software—similar to digital radiography—a phosphor storage plate scanner, and intraoral camera. Information can be viewed on screen and then saved into a patient’s record for analysis at a later date. This allows tracking of any regression or progression of the caries itself, Newman says.
References1. www.cdc.gov. Oral Health: Preventing Cavities, Gum Disease, and Tooth Loss. At a Glance 2008.
2. Young DA. Managing caries in the 21st century: today’s terminology to treat yesterday’s disease. J Calif Dent Assoc. 2006:34(5): 367-370.
3. Zandona AF, Zero DT. Diagnostic tools for early caries detection. J Am Dent Assoc. 2006;137(12):1675-1684.
4. Abrams SH, Scarlett MI, Trost L. Focus on dental caries management: beyond extension for prevention to minimal intervention. Woman Dentist Journal. March 2005.
5. Strassler HE, Sensi LG. Technology-enhanced caries detection and diagnosis. Compendium. 2008;29(8):2-13.
6. Samaras CD, Voiers DW. Digital caries detection. Inside Dentistry. 2008;4(6): 80-85.
7. Berg JH. The marketplace for new caries management products: dental caries detection and caries management by risk assessment. BMC Oral Health. 2006;6(Suppl 1):S6.
8. Bader JD, Shugars DA. A systematic review of the performance of a laser fluorescence device for detecting caries. J Am Dent Assoc. 2004;135(10):1413-1426.
9. Ricketts D. The eyes have it. How good is DIAGNOdent at detecting caries? Evid Based Dent. 2005;6(3):64-65.