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NIH: Consensus Development Conference on Diagnosis and Management of Dental Caries Throughout Life: Background

NIH organized conference that produced consensus statements on important and controversial topics in medicine and dentistry.

Diagnosis of Root Caries

David W. Banting, D.D.S., Ph.D., DDPH, M.Sc., FRCD(C):

Diagnosis of Root Caries

It is not surprising that the Research Triangle Institute (RTI) Evidence Report on the Diagnosis and Management of Dental Caries (2000) was unable to identify any reports on the diagnosis of root caries. There simply are no evaluations of diagnostic methods for root caries that satisfy all of the prerequisites of histological validation, commercial availability, professional application, and comparative clinical study. Nevertheless, there does exist a rather extensive literature on the diagnosis of root caries.

Clinical Root Caries

There is little disagreement regarding the distribution of root caries lesions. Root caries, by definition, occurs on the root of the tooth. It can occur wholly on the root of the tooth or spread from the crown of the tooth to the root. It can occur on its own or around existing restorations.

Root caries occurs most often at or close to the cemento-enamel junction. This has been attributed to the location of the crest of the gingiva at the time conditions were favorable for caries to occur. The location of root caries has been positively associated with age and periodontal disease, which is consistent with the concept that root caries occurs in a location adjacent to the crest of the gingiva where plaque accumulates (i.e., within 2 mm). Most root caries occurs on the proximal (mesial and distal) surfaces, followed by the facial surface. Early root caries tends to be diffuse and tracks along the cemento-enamel junction of the root surface.

Clinical Signs of Root Caries

Clinical diagnosis is the process of recognizing diseases by their characteristic signs and symptoms. It is an imperfect process because there is considerable variation in both the signs and symptoms in individual subjects and in the interpretation of those signs and symptoms by different clinicians. Nevertheless, clinical observations are powerful determinants of diagnosis and prognosis. The most commonly used clinical signs to diagnose root caries utilize visual (contour, surface cavitation, color) and tactile (surface texture) parameters. There are usually no reported clinical symptoms of root caries, although pain may be present in advanced lesions.

Visual-Tactile Diagnosis of Root Caries

Using traditional methods of visual-tactile diagnosis for root caries can produce a correct diagnosis, but not until the lesion is at an advanced stage. Because of the fundamental differences in coronal and root caries, enamel caries is more likely to be confidently diagnosed at an earlier stage than root caries.

Several investigators have therefore advocated expanded classification schemes for visual-tactile root caries diagnosis that incorporate lesion activity and treatment implications. Although additional criteria can generate more information to assist with diagnosis, they can also generate more variability. Despite the subjectivity that is inherent in interpreting the clinical signs used for root caries diagnosis, acceptable interexaminer reliability has been achieved in many clinical studies. Table 1 shows the findings on several measures of examiner reliability as reported in recent studies involving clinical diagnosis of root caries.

Table 1. Reliability of visual-tactile diagnosis of root caries


Kappa Statistic (surfaces)

Intraclass Correlation Coefficient (subjects)

Agreement (percent)

Bauer et al., 1988


0.83- 0.96


Fejerskov et al., 1991



Saunders and Handelman, 1991



Graves et al., 1992






Ravald and Birkhed, 1991




Wallace et al., 1993




Mojon et al., 1995

poor agreement


Rosen et al., 1996

0.30- 0.511

0.55- 0.751


1Excludes filled surfaces

Intraexaminer reliability has been shown to be slightly, but not dramatically, better than interexaminer reliability in diagnosing root caries.

Clinical diagnosis is an estimate of the probability that a patient has a specific condition after taking into account possible risk factors, clinical findings, and how commonly the disease occurs in the population. The information gained during clinical examination of the patient, together with the clinician�s knowledge of the disease and his or her own clinical experience, is (consciously or otherwise) collated, analyzed, and assimilated into a "best guess" of the likelihood of a condition being present. This is the "art" of clinical diagnosis, and clinicians can become highly skilled at it. Although clinical diagnosis uses the concept of probability, it relies on practical knowledge and experience rather than the laws of probability. But because there is a high level of uncertainty associated with the diagnosis of dental caries in general and root caries in particular, clinicians have looked to other diagnostic tests for assistance.

Diagnostic Tests for Root Caries

Two central issues arise in diagnostic tests. The first relates to the validity of the test, the second to whether the test can replace or supplement what is presently being used for diagnosis. Selecting the most appropriate diagnostic test is a complex matter that must take into account test characteristics, the clinician�s "best guess" of the likelihood of the disorder being present, and the purpose of applying the test. Clinicians should be particularly interested in test specificity, since the positive predictive value will always be better with a test that has high specificity. Table 2 presents the characteristics of the diagnostic tests that have been used to diagnose root caries. Guidelines are available to assist the clinician in determining whether or not a particular test is indicated and the steps involved in applying the test and interpreting the result.

Table 2. Characteristics of diagnostic tests for root caries



Study Type




Mutans Streptococci

Banting, 1988

in vivo





Ravald and Birkhed, 1991

in vivo





Banting, 1988

in vivo




Ravald and Birkhed, 1991

in vivo





Nordenram, 1988

in vivo




Salivary secretion rate

Ravald and Birkhed, 1991

in vivo




Salivary buffer effect

Ravald and Birkhed, 1991

in vivo




Oral sugar clearance time

Ravald and Birkhed, 1991

in vivo




Fluorescent dye

van der Veen and ten Bosch, 1993 van der Veen et al., 1996 van der Veen and ten Bosch, 1996

in vitro



Fluogenic enzyme assay

Collier et al., 1993

in vivo


r= 0.87

Electrical conductivity

Baysan et al., submitted

in vivo


r= 0.76

Consensus Needs Regarding the Diagnosis of Root Caries

Terminology.The terminology used for root caries diagnosis is not standardized, a situation that gives rise to confusion and even misinterpretation in root caries diagnosis. It therefore needs to be standardized in order to facilitate precision, understanding, and uniformity. Consensus is needed on the following terms:

  • Active root caries lesion
  • Inactive (arrested) root caries lesion
  • Primary root caries lesion
  • Secondary (recurrent) root caries lesion
  • Severity
  • Cavitation
  • Probing root lesions

Classification. Once a consensus is reached on terminology, a classification scheme needs to be developed for the determination of appropriate treatment modalities. Consensus is needed regarding the following classifications of root caries:

  • Sound (uncertain)/carious
  • Active/inactive
  • Noncavitated/cavitated
  • Observation/chemotherapeutic/debridement/restoration treatment and/or combinations of treatment.

Risk Assessment. Risk assessment methodology can be a useful approach to clinical diagnosis, but it is not widely used in dentistry. A consensus regarding the following aspects of risk assessment as it relates to the diagnosis of root caries is needed:

  • The range of pretest probabilities of root caries for different population subgroups
  • A "rule of thumb" guideline for test and treatment thresholds for root caries diagnosis.

Diagnostic Tests. Diagnostic tests should be used to supplement/confirm a clinical diagnosis but not as a substitute for clinical decision-making. For root caries diagnosis, a consensus is needed on the following aspects of diagnostic tests:

  • When should a diagnostic test be used?
  • What existing diagnostic tests are useful?
  • How should a diagnostic test be used to supplement/confirm a diagnosis regarding root caries?

Areas for Future Research Pertaining to the Diagnosis of Root Caries

The diagnosis of root caries would benefit from new clinical research designed to:

  1. Examine the validity of the clinical signs used to diagnose root caries by comparing them to a histological standard.
  2. Determine the characteristics of diagnostic tests for root caries relative to both clinical signs and a histological standard.


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Abstracts Index