Caries detection
Why do we diagnose caries?1- detecting and excluding disease
2- assessing prognosis
3- contributing to the decision-making process with regard to further diagnostic and therapeutic management
4-informing the patient
5- monitoring the clinical course of the disease.
diagnostic classifications
1-Visual–tactile caries examination
A-Sensible use of the probe
If the teeth are heavily covered by plaque, it may be necessary to clean the dentition before a proper caries diagnosis can be performed .Sticky adhering plaque covering a chalky/ opaque enamel lesion is strongly indicative of activity.
The probe serves two purposes: first, to remove the biofilm (using the side of the probe) to check
for signs of demineralization and surface break and, secondly, to ‘feel’ the surface texture of a lesion, as sensed through minute vibrations of the instrument by the supporting fingers when moving the tip of the probe at an angle of 20–40 degrees across the surface . It may take some training to learn this tactile skill, but once it has been acquired it is an important adjunct to the visual assessment.
A clinical caries examination performed according to these principles takes about 5–10 min, depending on the caries status of the patient.
B-Additional aids in visual–tactile caries diagnosis
1-Tooth separation
It can help to identify the presence of a cavity on contacting approximal surfaces. With this technique orthodontic elastic separators are applied for 2–3 days around the contact areas of surfaces to be diagnosed, after which access to inspection and probing .
disadvantage
1- accessibility for inspection after tooth separation is not always improved as much as needed,
2-and the use of the technique may create some discomfort, especially in patients with established dentitions.
3-it requires an extra visit.
at present the technique is not recommended for routine use in general practice.
2-Magnification
Some contemporary textbooks advocate the use of magnification in caries diagnosis. Indeed, most dentists above the age of 40 should be concerned with potential eyesight difficulties and wear glasses.
2-radiographic method
The most commonly used radiographic method for detecting caries is the bitewing technique. The purpose of bitewing examination is to detect lesions that are clinically ‘hidden’ from a careful clinical–visual examination, such as when an adjacent tooth prevents the dentist from seeing an approximal lesion. The radiograph will also help to estimate the depth of this lesion. Furthermore, bitewing radiographs should always be examined for occlusal caries in dentin.
limitations
1-not determine whether a cavity is present. As with any diagnostic method.
2-there are also inherent errors.
3-the risks of exposing a person to ionizing radiation have to be considered and balanced against the benefits of bitewing examination.
A-Bitewing with film and with digital receptors
Digital radiography is now increasingly used in clinical practice and radiography based on film may therefore not be relevant in the near future. Current digital intraoral radiography systems and recently developed fast dental films have been reported to be as accurate as traditional films for the detection of caries .
advantages of digital radiography :
1-The facilities for density and contrast enhancement can optimize the diagnostic quality and reduce retakes.
2- The radiation dose is lower.
3- No wet chemicals are involved in processing.
4- The technique is less time consuming.
B-Tuned aperture computed tomography
Recently introduced diagnostic methods based on digital radiography are tuned aperture computed tomography (TACT) and limited cone beam computed tomography.
Both methods construct radiographic slices of different thickness of teeth. The slices can be viewed for the presence of radiolucencies. In addition, the slices can be brought together in a three-dimensional computer model called a pseudohologram. These slices and pseudoholograms perform adequately in the detection of small primary and recurrent carious lesions.
Limitation:
1- performance in occlusal and approximal caries diagnosis is not significantly better than
film radiography and digital radiography .
2-the device is currently too expensive to be used in a small clinical practice.
3-Methods based on light
A-Laser light-induced fluorescence
Laser light is composed of electromagnetic waves with equal wavelengths and equal phases. Some materials possess the characteristic of fluorescence when illuminated with (laser) light. Fluorescence is a phenomenon by which the wavelength of the emitted light (coming from the light source) is changed into a larger wavelength as it travels back for detection. The larger wavelength is caused by some loss of energy to the surrounding tissue and therefore will have a different color from the emitting light. By using a filter through which only the fluorescent light may pass, the intensity of the fluorescent light can be measured. The intensity of the fluorescent light is proportional to the amount of material that causes the fluorescence.
B-DIAGNOdent
When red light with a wavelength of 655 nm is applied, caries-induced changes in teeth lead to increased fluorescence.
The DIAGNOdent is based on this principle. The fluorescent light is measured and its intensity is an indication of the depth of the caries lesion. The intensity of the fluorescent light is displayed as a number ranging from 0 to 99, with 0 indicating a minimum and 99 a maximum of fluorescent light .
Clinically visible whitespot lesions are measurable with this device.
C- Fiber-optic transillumination (FOTI)
is a diagnostic method by which visible light is transmitted through the tooth from an intense light source, e.g. from a fine probe with an exit diameter of 0.3–0.5 mm. If the transmitted light reveals a shadow when the tooth is observed from the occlusal surface this may be associated with the presence of a carious lesion. The narrow beam of light is of crucial importance when the technique is used in the premolar and
molar region. For optimal performance the probe should be brought in from the buccal or lingual aspect at an angle of about 45 degrees to the approximal surfaces pointing apically, while looking for dark shadows in the enamel or dentin . Shadows are best noticed when the office light is switched off.
Advantage:
1-a simple
2- fast
3- cheap
4- method well known to most practitioners for diagnosing approximal caries in the anterior teeth.
D- Digital imaging fiber-optic transillumination
The technique of digital imaging fiber-optic transillumination (DIFOTI) was introduced to replacing the human eye in Fiber-optic transillumination with a receptor that lesions involving over half of the enamel were better detected than lesions restricted to only the outer half of enamel for both smooth and occlusal surfaces. In other words, DIFOTI may not be able to detect small lesions, such as lesions within half of enamel thickness, and this is not as good as a visual examination .