Radiographic examination can be helpful in locating proximal caries and undermining caries and secondary caries [1]. 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.

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.

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.