The presentation of dental caries is highly variable. However, the risk factors and stages of development are similar. At first, it may appear as a small chalky area (smooth caries), which may eventually develop into a large cavity. Sometimes caries may be directly visible. However, other methods of detection such as x-rays are used for less visible areas of the teeth and to judge the extent of the destruction. The laser allows for detection of dental caries without any ionizing radiation and is now used to detect interdental decay (between the teeth). Detection solutions are also used during dental restorations to reduce the chance of recurrence.[citation needed]
Initial diagnosis involves examining all visible tooth surfaces with a good light source, dental mirror, and probe. Dental x-rays (X-rays) may show tooth decay before it appears in another way, especially cavities. Large areas of dental caries are often visible to the naked eye, but smaller lesions are difficult to identify. Visual and tactile examinations, along with radiographs, are used frequently among dentists, particularly for the diagnosis of pit and fissure caries.[87] Early, non-occult caries is often diagnosed by blowing air across the suspected surface, which removes moisture and alters the optical properties of non-mineralized enamel.
Some dental researchers have cautioned against using dental explorers to find caries,[88] particularly sharp-ended explorers. In cases where a small area of the tooth has begun to demineralize but has not yet been stimulated, pressure from the dental explorer may cause a cavity. Because the caries process is reversible before a cavity appears, it may be possible to stop tooth decay with fluoride and remineralize the tooth surface. Where a cavity is present, a restoration will be needed to replace the missing tooth structure.
Sometimes, pit and fissure caries can be difficult to detect. Bacteria can penetrate the enamel to reach the dentin, but then the outer surface may remineralize, especially if fluoride is present.[89] These caries, sometimes referred to as “hidden caries,” will still be visible on X-ray radiographs, but a visual examination of the teeth will show that the enamel is intact or minimally perforated.
The differential diagnosis of dental caries includes dental fluorosis and developmental defects in the tooth including hypomineralization and tooth hypoplasia[90].
An early acute lesion is characterized by demineralization of the surface of the tooth, altering the optical properties of the tooth. Technology utilizing laser spot image (LSI) techniques may provide a diagnostic aid for early detection of lesions.[86]
