Conventional diagnosis methods
Black or chalky area or a formed cavity can be seen
Probe can be used to locate affected area, the area of dentinal hypersensitivity, and pulp exposure
The reaction to percussion is always negative
Special diagnostic methods
Radiolucency on hard tissue due to demineralization is identified as carious lesion
Cold and hot irritation test
The response of dental pulp toward cold and hot irritation can determine the severity of caries
Dental floss examination
Dental floss can diagnose caries on proximal contact area
Diagnostic cavity preparation
After removing supportless enamel, the practitioner can obtain well a vision on hidden carious lesion
The new technology of caries diagnosis
This system uses fiber transillumination for potential caries diagnosis
Electrical impedance technology
This technology is an alternative way for occlusal pit and fissure caries diagnosis
It is a new method for caries detection by measuring the wave that reflects back from tooth structure
Elastomeric separating modulus technique
Elastomeric separating modules are used to separate apart adjacent tooth temporarily for examination of proximal surfaces
This technique can show the presence of caries and estimate the depth of carious lesion
Quantitative laser fluorescence technique
Autofluorescence is light emission phenomenon of biological structure
The differential diagnosis of the superficial caries
The key points of the differential diagnosis for caries are glossiness and smoothness, predilection site, symmetry of the lesion, and progress of the lesion
5.1 Conventional Diagnosis Methods
When making an examination for dental caries on suspected sites, we can find black or chalky area or a formed cavity. The interproximal marginal ridge area has ink stain discoloration under the enamel or a visible cavity. For observation on tooth cervical areas, the cheek and tongue should be pulled away to fully expose buccal and lingual surface of posterior teeth. Depending on the inspection, we can get a general scope of carious damage.
The sharp probe is used to inspect the suspicious areas. With the help of the probe, the depth and extension of cavity can be examined. If a proximal cavity is suspected and cannot be located through an inspection, the probe is useful to locate affected area when it is hooked by the edge of the cavity. The probe can also be used on the tooth surface to locate the area of dentinal hypersensitivity. Pulp exposure can also be located while examining the deep carious lesion.
Caries does not cause periodontal and periapical inflammation, so the reaction to percussion is always negative.
5.2 Special Diagnostic Methods
5.2.1 Radiographic Examination
Radiographic examination can be helpful in locating proximal caries and undermining caries and secondary caries . It can also be used to assess the proximity of caries to pulp chamber. Periapical and bite-wing radiographs are commonly used for clinical assessment of caries. Radiolucency on hard tissue due to demineralization is identified as carious lesion. A series of researches have revealed that more than half of proximal caries are seen on the radiograph. Since the radiograph is a two-dimensional image, the diagnosis result should be analyzed and combined with clinical examination. Proximal caries should be distinguished from normal triangular low-density areas in the cervical region of the tooth. Secondary caries should be differentiated from low-density basing materials on the floor of the cavity.
5.2.2 Cold and Hot Irritation Test
The response of dental pulp toward cold and hot irritation is examined during cold and hot irritation test. Examination is done by putting chloroethane-soaked cotton ball or hot gutta-percha stick on the surface of the tooth, and the patient’s response is evaluated. These external stimuli can elicit acute pain. The pulp is supposed to be healthy if pain disappears right after removal of stimuli. But if the pain is lingering, the pulp is likely to be in irreversible inflammatory. When cold water is used as stimulus, it is important to note that the flow of water may affect the accurate location of carious cavity. At last, caries should be differentiated from dentin hypersensitivity.
5.2.3 Dental Floss Examination
Caries on proximal contact area is difficult to be examined by inspection and probing. Dental floss can be used as a convenient method. By putting a dental floss across the embrasure of the suspicious tooth surface and moving the floss horizontally in a seesaw motion, the examiner can experience the roughness of the surface. The floss will be torn if caries is present. Examination with floss can be misled by dental calculus.