Diagnosis and Registration of Carious Lesions
Introduction
The coronal carious lesion starts as a clinically undetectable subsurface
demineralization. With further progression, it will eventually become clinically
detectable, and can then be classified according to type, localization, size, depth, and
shape (see Table 15).
Apart from for the occult fissure lesion penetrating deeply into the dentin, dilemmas
in clinical detection and registration arise not with the advanced lesion, but primarily
with the early lesion (confined to the outer enamel), the noncavitated lesion of dentin,
recurrent caries (around the margins of restorations), and subgingival root caries. This
is further complicated by the fact that diagnostic methods and criteria may vary,
depending on the purpose of the examination. For the epidemiologist, measuring
caries prevalence or assessing treatment needs at the community level, or for the
dental researcher, measuring caries increments in relation to the efficacy of an
anticaries agent, decisions about the presence of a lesion are not complicated by the
obligation to consider treatment options for the individual patient. In general, the
epidemiologist surveying a population confines a positive diagnosis of caries to
unequivocal cavitation, to reduce variability. Most guidelines for surveys specifically
state that questionable lesions should be coded as sound.
On the other hand, for the clinician, detection of a lesion, whether confined to enamel
and therefore potentially reversible, or frank cavitation, raises the question of
appropriate treatment. In addition, different tooth surfaces present different problems
for correct diagnosis of the questionable lesion. In other words the diagnostic method
of choice depends on the purpose of the examination.
According to Pitts (1997), the ideal method or tool for diagnosis of carious lesions
would be noninvasive and provide simple, reliable, valid, sensitive, specific, and
robust measurements of lesion size and activity, and be based on biologic processes
directly related to the carious process. It should also be affordable, acceptable to
dentists and patients, and allow early implementation in both clinical practice and
research settings. Its use should promote informed and appropriate preventive
treatment decisions, enhancing long-term oral health. Unfortunately, there is at
present no single, all-embracing method that fulfills these requirements. While
awaiting further technologic development, dentists and researchers have to select the
combination of methods that is most appropriate to the particular diagnostic task at
hand.
Diagnostic tools
Some decades ago, visual diagnosis (light and mirror) and probing, supplemented by
bitewing radiographs, were the only tools available for clinical diagnosis of caries.
For epidemiologic surveys and for examination of most patients, these are still useful
tools. However, the last 10 years have seen a considerable increase in the assortment
of diagnostic tools based on new technology. The following methods are now
available:
1. The visual method used by many general practitioners
2. The visual-tactile method with light, mirror, and gentle probing
3. The conventional visual method used in European epidemiologic surveys
4. The meticulous clinical visual method
5. The visual method with temporary elective tooth separation
6. The visual method with temporary elective tooth separation and impression of the
approximal lesion
7. The conventional bitewing radiographic method
8. The digital radiographic method
9. The computer-aided radiographic method
10. The fiber-optic transillumination (FOTI) method
11. The electrical conductance (fixed frequency) method
12. The alternating current impedance spectroscopy technique (ACIST)
13. The endoscopic filtered fluorescence (EFF) method
14. The quantitative laser (light) fluorescence (QLF) method
The accuracy (sensitivity and specificity), usefulness, and cost effectiveness of these
methods vary considerably. Some are very quick and inexpensive, but subjective, and
are therefore useful for large-scale epidemiologic surveys (the visual-tactile and
European epidemiologic methods), while others are objective and offer quantitative
diagnosis but are time consuming and require costly equipment (ACIST, EFF, and
QLF). At present, the latter methods are restricted to research projects.
