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
|
Investigator(s) |
Kappa Statistic (surfaces) |
Intraclass Correlation Coefficient (subjects) |
Agreement (percent) |
|
Bauer et al., 1988 |
0.83- 0.96 |
||
|
Fejerskov et al., 1991 |
0.88 |
||
|
Saunders and Handelman, 1991 |
90 |
||
|
Graves et al., 1992 |
0.94 |
||
|
|
|||
|
Ravald and Birkhed, 1991 |
0.71 |
87 |
|
|
Wallace et al., 1993 |
0.80 |
98 |
|
|
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
|
Test |
Investigator |
Study Type |
Se |
Sp |
Other |
|
Mutans Streptococci |
Banting, 1988 |
in vivo |
0.46 |
0.93 |
ppv=0.75 |
|
Ravald and Birkhed, 1991 |
in vivo |
0.36 |
0.89 |
||
|
Lactobacilli |
Banting, 1988 |
in vivo |
0.38 |
0.74 |
|
|
Ravald and Birkhed, 1991 |
in vivo |
0.59 |
0.84 |
||
|
Radiology |
Nordenram, 1988 |
in vivo |
0.84 |
0.67 |
|
|
Salivary secretion rate |
Ravald and Birkhed, 1991 |
in vivo |
0.16 |
0.95 |
|
|
Salivary buffer effect |
Ravald and Birkhed, 1991 |
in vivo |
0.47 |
0.78 |
|
|
Oral sugar clearance time |
Ravald and Birkhed, 1991 |
in vivo |
0.26 |
0.85 |
|
|
Fluorescent dye |
van der Veen and ten Bosch, 1993 van der Veen et al., 1996 van der Veen and ten Bosch, 1996 |
in vitro |
r=0.91-0.96 |
||
|
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:
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:
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:
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:
Areas for Future Research Pertaining to the Diagnosis of Root Caries
The diagnosis of root caries would benefit from new clinical research designed to:
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