Understanding risk is essential to the practice of dentistry

Clinical risk assessment is central to dental practice. Dentists routinely gather information regarding a patient’s medical and dental histories, and clinical findings are included in the patient’s record. A dentist’s professional judgment and ability to integrate clinical findings with knowledge of oral disease processes, range of treatment possibilities, evidence-based treatment recommendations, experience with those treatments, and the needs of the patient are all part of clinical risk assessment and contribute to the identification of appropriate treatment. When the appropriate treatment can be delivered correctly to the patient, at the correct time, risk for a disease or condition can be lessened. The benefit can be measured in terms of improved health and perhaps in terms of decreased cost as well.

Clinical risk includes three distinct functions: risk assessment, risk management, and risk communication. Risk assessment is the determination of the likelihood that an adverse outcome will occur, based on the identification and weighting of risk factors. Risk management is the action taken to mitigate adverse outcomes. Risk communication is the sharing of risk information with the patient. Together, these three functions present an opportunity for more “individualized” oral health care, more consumer participation in clinical decision-making, and more efficient use of oral health care resources.

The focus of the dental profession is disease prevention, and risk assessment and management are integral to disease prevention. The tools and resources with which to assess and manage risk continue to develop. Deeper understanding of risk factors leads the practitioner to move toward care that is based on risk assessment. The risk of periodontal disease and its connection to systemic diseases compels the profession to expand its knowledge of risk factors for oral disease. The understanding and management of caries risk continues to develop. Although it always will be necessary to address active disease, risk assessment will become an ever-growing dimension of oral health care that will aid the practitioner in moving patient care to prevention and early intervention.

Valid and reliable risk assessment instruments are needed

How can a dentist predict future disease or need for care, based on information that can be collected today? Formal assessment of risk factors helps in making this judgment. Formal clinical risk assessment tools are relatively recent developments in dentistry, however, and validation studies are still in the early stages. Risk assessment instruments now available tend to focus on caries, periodontal disease, and oral cancer. Risk factors for caries, periodontitis, and oral cancer have been studied most extensively, because caries and periodontitis are widespread and oral cancer often can be life threatening.

Dental caries and periodontal disease are highly prevalent conditions, so prevention and treatment of these two diseases is a priority. Although the prevalence of caries has declined in much of the United States population, it still is highly prevalent in people of low socioeconomic status. Its prevalence also is increasing among older adults, because they are remaining dentate throughout their lives. Recent data also indicate an increase in caries incidence in very young children.

The ramifications of periodontal disease now are thought to be greater than in previous years because of their associations with some systemic conditions. Twelve percent of adults aged 25 to 34 years have at least one site of a 4-mm attachment loss, and this percentage increases with age.

Oral cancer is relatively rare, but it presents a serious impact on patients’ quality of life and survival. There are few formal risk assessment instruments for oral cancer at this time, but there are a number of screening tools. The profession places a high priority on prevention and treatment of oral cancer, and dentists are urged to evaluate patients carefully for oral cancer.

Formal assessment instruments make it easier to discuss risk factors because they present a common vocabulary and conceptual model. Instruments group risk factors that are similar, describe their action in the disease process, and sometimes weight risk factors. They also tend to increase objectivity in the evaluation process.

There are many models, but risk factors generally fall into hierarchies or categories that describe how directly they are related to the cause of disease and how they act independently or synergistically with other risk factors. The categorization of a risk factor is fluid as evolving evidence-based scientific study provides more data about how a risk factor contributes to the disease process. For example, the understanding of how oral pathogens act in the development of periodontitis changed as scientific data showed that specific pathogens are more important in the development of periodontitis than the quantity of numerous pathogens. Risk factors may be categorized as direct factors, which may be causes of disease, potentiators of disease, and markers of disease.

A direct risk factor is considered to be a major factor of a given disease and may have an independent effect in the development of a specific disease. A high level of the oral pathogen Streptococcus mutans is a strongly associated risk factor for caries. This risk factor is documented in the scientific literature as being a direct causative factor of caries.

In other instances, risk factors are suspected of having a link to oral disease because they have very strong statistical associations with it, but causality has not yet been established. For example, an association between oral disease and some systemic processes, such as chronic inflammation, has been found. Direct risk factors also can act synergistically to increase the risk of disease.

Potentiators of disease are factors that are known either to act upon the direct or major risk factors to increase their effect or act upon the patient in a way that increases the patient’s susceptibility. In either case the potentiator increases the risk of disease or further predisposes the patient to disease. Although potentiating factors tend to be lifestyle habits such as poor oral hygiene and diet, they are not exclusively lifestyle factors. For example, a symptom of Sjögren’s syndrome is a dry mouth; and a dry mouth can act to potentiate the development of caries.

Risk factors also may include markers of disease, such as incipient caries, restored lesions, mobile teeth, missing teeth, and biochemical characteristics of saliva, blood, or other bodily fluids that are associated with disease. Markers are not necessarily causes of the disease but show that the disease is or has been present.

The interaction of risk factors can have a substantial effect on the development or progression of disease, and risk assessment models suggest that an estimation of risk should be based on the combination of both independent and associated factors. Acting synergistically, risk factors may increase the patient’s absolute risk of disease. An example is the interaction between high levels of Streptococcus mutans , a diet high in simple carbohydrates, inadequate exposure to fluoride, and the susceptibility of the tooth, resulting in caries. These factors can be potentiated or modified by a host of behavioral and environmental factors, such as oral hygiene practices, smoking, socioeconomic status, access to fluoridated drinking water, and patient attitudes and knowledge about health and disease.

The dental profession currently has a better understanding about what risk factors are than about what their interactions are. For estimating a patient’s total level of risk, dental risk assessment forms, developed to date, use a simple listing of risk factors. A patient’s risk level is classified as high, medium, or low, based on educated approximations of the threshold number of risks that could separate each category. Some assessment forms attempt to weight each risk factor, giving greater weight to factors that are known to play a more direct role in the development of disease. The limitation of weightings is that they generally are based only on a consensus of expert opinion regarding the strength of a particular risk factor relative to the other risk factors. At this time quantification of risk often is subjective (and this subjectivity is one reason why no single form is universally accepted for risk assessment).

Risk generally is applied very narrowly by third-party payers, who frequently assign benefits for caries by the evidence of previous caries activity, without taking the broad range of risk factors into account. Because the disease already is present or has been present, the risk captured by third-party payers is the progression of caries, rather than the prevention of the disease. Some would argue that planning to address risk from this perspective is too little, too late.

Caries risk assessment tools have been developed by various organizations, agencies, and proprietary vendors. The multivariate nature of the risk of caries has led to several unique approaches. There are at least five clinical caries risk assessment protocols in somewhat widespread use. Each of these protocols emphasizes different aspects of caries risk assessment.

The American Dental Association/Food and Drug Administration Radiographic Guidelines (A/FRG), first developed in 1985 and revised in 2004, include advice on caries risk assessment. This information can be integrated into the necessity for radiographic evaluation and is not formatted into a concise tool or form that can be used to document patient risk factors. Its main advantage is the flexibility in assessment given to the dentist when determining a patient’s risk level.

The Caries Assessment Tool (CAT) was developed by the American Academy of Pediatric Dentists. It was introduced in 2002 and was developed for risk assessment of infants, children, and adolescents. The tool was revised in 2006 and incorporates risk factors and levels or degrees of risk in a chart form. Some factors that apply mainly to adults, such as tobacco use, are not included in the CAT.

Caries management by risk assessment was developed by John Featherstone at the University of San Francisco. Two assessment forms are used, one for children under 6 years of age and one for all other patients. This risk assessment strategy includes documentation of protective factors and has been implemented at the University’s dental clinics. The major disadvantage of these forms for dentists in private practice is that some of the assessment parameters, such as bacteriologic identification and measurement of salivary flow, are not typically performed in most private dental offices. The incorporation of protective factors as part of the assessment adds another layer of complication in assessing risk.

A computerized caries risk assessment program, the Cariogram. was developed at the University of Malmo. This program is available on the Internet and is not dependent on age to determine caries risk. All risk factors are graded on a continuum of 0 (low risk) to 3 (high risk). The assessment is presented graphically as a pie chart and can include a written assessment. Assessments of the population are required before individual risk factors can be entered into the program. The program requires assessments about populations before individual risk factors are entered. Three of the nine elements that are assessed are not commonly performed in private dental offices in the United States: levels of S treptococcus mutans , the buffering capacity of the patient’s saliva, and saliva secretion rate.

A proprietary software program, PreViser ^™ , that assesses risks for caries, for fracture, and for the development of root surface caries is available. The software program takes into account the patient’s age. Required risk parameters are submitted to the company over the Internet, and the company then generates a risk profile. Risk is assessed as low, moderate, or high. Individualized recommendations for prevention, oral hygiene, visits to the dental office, and communications with the patient also are provided with the risk assessment.

In 2004, the American Dental Association formed a Caries Risk Assessment Workgroup that evaluated the publicly available caries risk tools and found that none of the existing tools was adequate to assess caries risk simply in general dental practices. The A/FRG advice was not available in a form for purposes of documentation; the CAT was not designed to be used for an all-inclusive population; the caries management by risk assessment and Cariogram included risk factors that most general dentists in practice would not likely record; and the risk basis for the PreViser tool is not clear. In December 2008 the American Dental Association’s Board of Trustees approved two caries risk assessment forms that were designed to record risk factors and to be used as patient communication tools.

There are two major tools available to assess the risk for periodontal disease. The first, from the American Academy of Periodontology, is Internet based. Following submission of 12 self assessments, a report is generated with an assessment of the risk level (low, medium, or high) for developing periodontal disease.

An Internet-based periodontal risk and disease assessment also is available from PreViser. In addition to assessing the level of risk from very low (1) to very high (5), this program provides an assessment of disease from healthy (1) to severe gum disease (100) that is based on the clinical findings of the dental office. A report with interventions, possible treatments, and the frequency for prevention and maintenance is transmitted to the dental office along with the assessment.

An oral cancer risk assessment tool is included in the PreViser suite of products, with risk reported on a scale of 1 (less risk) to 5 (greater risk). The individualized risk value seems to be based on the reported demographic characteristics and social habits of the patient.

Salivary testing may provide objective measures of oral disease. There is some evidence that it may help with the risk assessment data for oral cancer. The analysis of oral bacteria and other oral biochemical factors offer more measurable risks for developing oral disease. Colony counts of Streptococcus mutans and measures of salivary acidity provide risk assessment data for caries. Analysis of oral bacteria, subgingival temperature, and crevicular fluid may provide an indication of risk for periodontitis. At this time, however, most dentists do not perform such analyses on a routine basis to detect signs of disease.

Dentists usually assess risk informally and intuitively by looking for early symptoms of disease and rely on the patient to provide accurate information about lifestyle, medical history, and other risk factors. Risk can be a moving target, because a patient’s risk of disease can change over time, sometimes in a matter of months. The dentist can reassess risk at every visit by asking the patient if there has been any change in lifestyle and habits and by conducting an oral examination.

In addition to their clinical usefulness, formal risk assessments can serve as educational tools. The dentist can use them in talking with the patient and provide anticipatory guidance. They provide an organized and tangible format for helping the patient understand factors that contribute to the disease process and the relative importance of those factors. Assessments also can point out the difference between factors that can be controlled directly by the patient and those that must be managed through professional care, showing the degree to which dental disease can be controlled. This explanation may help clarify for the patient what periodic visits accomplish and may motivate the patient to be more compliant with ongoing care.