Diagnosis of root cariesDefinition and classificationRoot caries usually appears as a shallow area, less than 2 mm deep, a mostly noncavitated, ill-defined, softened, and often discolored lesion, characterized by destruction of cementum and penetration of dentin. Several definitions and classifications have been proposed; Hix and O’Leary (1976) defined root caries as “a cavitation or softened area in the root surface which might or might not involve adjacent enamel or existing restorations (primary and recurrent lesions).

Diagnosis of approximal cariesThe issues to be considered by the clinician with respect to caries of the approximal surfaces are similar to those considered at other sites: Is the surface sound, or is there a lesion? If so, how advanced is the lesion¾involvement of enamel only, enamel and dentinal involvement, or pulpal exposure? Finally, is there cavitation?  Diagnostic methodsMeticulous visual examinationIn the thin anterior teeth, both noncavitated and cavitated approximal lesions are readily detectable by meticulous clinical visual examination.

Diagnostic methodsIn typical fissures, and particularly in atypical sticky fissures (see Fig 203), most of the early stages of the lesion are hidden from the naked eye, although in a clean, dry fissure, it might be possible to observe active noncavitated white-spot lesions on the walls. Soon after eruption, most of these lesions are arrested (see Figs 174, 204a-c, 205c) and take up a brown stain from items in the diet. This diagnostic problem was recognized many years ago by GV Black (1908) who wrote: Very many pits and fissures show evidence of some slight softening in early youth, which is stopped by the coming of immunity or some change of local conditions.

Diagnosis of occlusal cariesIt might be expected that occlusal carious lesions would be fairly easy to diagnose,  because unlike approximal and subgingival root surfaces, these surfaces are readily accessible for visual inspection. However, clinically (visual or visual-tactile by probing) or radiographically, diagnosis of occlusal lesions is a delicate problem, because of the complicated three-dimensional shape of the occlusal surfaces, incorporating fossae and grooves with a great range of individual variations.

Quantitative laser (light) fluorescence methodA method that is related to EFF and is attracting considerable interest is the quantitative laser fluorescence technique. At present, QLF can assess only accessible smooth surfaces and is limited to part of the enamel thickness.The principle for the QLF method is shown in Fig 199. The excitation is performed with blue-green light (488 nm) from an argon ion laser. The fluorescence in the enamel, occurring in the yellow region (approximately 540 nm), is observed through a yellow high-pass filter (520 nm) to exclude the tooth-scattered blue laser light.

Endoscopic filtered fluorescence methodPitts and Longbottom (1987) explored the use of EFF for the clinical diagnosis of carious lesions and compared results with conventional alternatives on occlusal and approximal sites. This work developed to include the use of an intraoral video system for caries detection, the prototype “videoscope.” Now that commercial intraoral cameras are increasingly available in practices, this may prove to be of practical clinical importance.

Alternating current impedance spectroscopy techniqueA more sophisticated approach to lesion detection and measurement is to characterize the electrical properties of the tooth and lesion by using the ACIST, which scans multiple frequencies. The ACIST is new and has been evaluated only to a limited extent on whole carious teeth. However, the results to date are extremely encouraging, indicating 100% sensitivity and specificity at the D1 level and only a marginal decrease in specificity at the D3 level (Longbottom et al, 1996).

Electrical conductance (fixed frequency) methodElectrical methods of caries diagnosis are not new. There has been recent revival of interest in fixed frequency electrical devices, which show considerable promise for detection of occlusal and approximal lesions. A device is now commercially available in The Netherlands; similar machines were produced in the United States and in Japan some years ago. The electrical detection methods are seen by many as having the greatest potential for significantly improving diagnostic performance in the years to come.

Fiber-optic transillumination methodFiber-optic transillumination is a development of a classic diagnostic aid, advocated some 20 years ago, which has never gained wide acceptance. However, it should be a regularly used tool for diagnosis of caries, in the incisor and premolar regions at least, to supplement clinical examination and bitewing radiographs. Fiber-optic transillumination has enjoyed variable success in studies evaluating its performance, possibly because of failure to appreciate that the technique, like any other, requires an extended learning phase.

Computer-aided radiographic methodComputer-aided radiographic methods exploit the measurement potential of computers in assessing and recording lesion size. In the new Trophy 97 system an artificial intelligence software (Logicon Caries Detector) is integrated: Approximal carious lesions are diagnosed and evaluated with the aid of a unique histologic database, allowing graphic visualization of the size and progression of the lesion (Figs 197a to 197c).At both the D1 and D3 thresholds, computer-aided methods offer high levels of sensitivity for approximal lesions.

Digital radiographic methodDigital, filmless, techniques for intraoral radiography have been developed for several important reasons:1. Conventional film absorbs only a few percent of the x-rays that reach it, utilizing very little of the radiation to which the patient has been exposed.2. Poor darkroom procedure can lead to both unnecessarily high doses of radiation and loss of diagnostic information.3. Development of films is time consuming, and the developer and fixing solutions are hazardous to the environment.

Conventional bitewing radiographic methodSeveral factors have contributed to the general adoption of radiographic examination as an aid to the detection and subsequent treatment of caries:1. It discloses sites inaccessible to other diagnostic methods. Radiography facilitates detection of carious lesions at an earlier, potentially reversible stage. Usually, more approximal and occlusal lesions are recorded when clinical examinations are supplemented by radiography. 2. The depth of the lesion can be evaluated and scored, eg, by the radiographic index by Grondahl et al (1977), modified from Moller and Poulsen (1973): 0 = no radiographic changes in enamel; 1 = radiographic changes in enamel; 2 = radiolucency extending to the dentinoenamel junction; 3 = radiolucency penetrating approximately halfway through dentin; and 4 = radiolucency close to the pulp.

Visual method with temporary elective tooth separation and impression of the approximal lesionTemporary elective tooth separation, complemented by a localized impression of the opened interproximal space, allows a more sensitive diagnosis of cavitation than does the purely visual separation method. This also has the advantage of providing a replica as a reference for visual monitoring of changes in size or even measurement of serial impressions (Neilson and Pitts, 1993; Seddon, 1989).

Visual method with temporary elective tooth separationThe once popular technique of temporary elective tooth separation as an aid to diagnosis of caries in approximal smooth surfaces is now regaining popularity, albeit with more humane and less traumatic methods that seem acceptable to most patients and dentists. This method permits a more definite assessment of whether radiographically detectable approximal enamel (D1, D2) and dentin lesions (D3) are cavitated (Pitts and Longbottom, 1987; Pitts and Rimmer, 1992; Rimmer and Pitts, 1990).

Visual method used in European epidemiologic surveysProbing has been criticized for several reasons: It may allow transmission of  cariogenic bacteria from infected sites, it can irreversibly traumatize potentially remineralizable noncavitated lesions of enamel and dentin, and it may provide no more accuracy in diagnosis than visual inspection alone, particularly in the fissures and on the posterior approximal surfaces. Accordingly, a so-called European system of examination for surveys, based primarily on detailed visual examination, has been adopted by many epidemiologists.

Clinical visual-tactile methodThis method is based on a combination of light, mirror, and gentle probing and is used in most epidemiologic surveys in the United States. Caries is diagnosed if the tooth meets the American Dental Association criteria of softened enamel that catches an explorer and resists its removal (the so-called sticky fissure) or allows the explorer to penetrate proximal surfaces under moderate-to-firm probing pressure. Lighting is usually adequate, but the teeth are neither cleaned nor dried.

Visual method used in general practiceThe visual method, a combination of light, mirror, and the probe for detailed examination of every tooth surface, is by far the most commonly applied method in general practice worldwide. Although sensitivity is low and specificity is high, it may be possible to detect:1. Noncavitated enamel lesions (D1) on the free smooth surfaces (buccal and lingual), most anterior approximal surfaces, and the opening of some fissures 2. Clinically detected “cavities” limited to the enamel (D1, D2)3.

Diagnosis and Registration of Carious LesionsIntroductionThe coronal carious lesion starts as a clinically undetectable subsurfacedemineralization. With further progression, it will eventually become clinicallydetectable, and can then be classified according to type, localization, size, depth, andshape (see Table 15).Apart from for the occult fissure lesion penetrating deeply into the dentin, dilemmasin clinical detection and registration arise not with the advanced lesion, but primarilywith the early lesion (confined to the outer enamel), the noncavitated lesion of dentin,recurrent caries (around the margins of restorations), and subgingival root caries.

Root cariesAccording to Hix and O’Leary (1976), root surface caries is defined as “a cavitationor softened area in the root surface which might or might not involve adjacent enamelor existing restorations (primary and recurrent lesions).” Nyvad and Fejerskov (1987)introduced the definitions of active and inactive carious lesions of the root. Rootcaries may be classified as primary or secondary, cementum or dentin, active orinactive, and with or without cavitation (see Table 15). The lesions can also beclassified according to the texture (soft, leathery, or hard) and the color (yellow, lightbrown, dark brown, or black).

Dentin cariesWhether or not an active, noncavitated carious lesion in enamel will progress into thedentin and the rate of progression are determined by many factors:1. The overall estimated caries risk (C1 to C3) of the individual2. The rate at which the enamel lesion has developed3. The size, depth, and site of the enamel lesion4. The posteruptive age of the enamel5. The future efficacy of self-care and supplementary needs-related preventiveprogramsOn the approximal surfaces of the posterior teeth, the progression of a carious lesionthrough the enamel into the dentin can easily be followed on serial bitewingradiographs.