Dental caries is a pathological process of localized destruction of tooth tissues by microorganisms of dental plaque. (Latin: caries = rottenness). It is the most common cause of loss of teeth in children and young adults. The incidence of caries increases slowly with increasing age and the highest prevalence is found amongst teenagers. After this age period the prevalence of caries decreases. Individual teeth most affected are in order: first molar, second molar, second premolar, first premolar, central incisor and canine.
Caries originates on the external surface of an erupted tooth as ENAMEL CARIES or CEMENTAL CARIES. The disease may then progress rapidly or slowly towards the pulp with involvement varying from minute areas in pits to widespread coverage of tooth surface. Clinical Feature of Caries Depending on the location involved, caries may be classified1. pit and fissure
2. smooth surface (buccal, lingual and proximal surfaces)
3. root caries
PIT AND FISSURE CARIES:
This is the commonest carious lesion in humans. Occlusal fissures are deep invagination of enamel and can be extremely diverse in shape. The carious lesion more often starts at both sides of the fissure wall rather than at the base. The area may look chalky, yellow, brown or black due to discoloration. These clinical alternations of the enamel occur early in initial caries and without any apparent break in the enamel surface.
SMOOTH SURFACE CARIES:
On smooth enamel surfaces, the earliest visible changes are usually manifest as a loss of transparency, resulting in an opaque chalky region known as "WHITE SPOT". In locations where caries progresses more slowly or becomes arrested, brown or yellow pigmentation of the enamel may be seen.
ROOT CARIES:
Root caries involving both cementum and dentin typically appears as a slowly progressing chronic lesion. Clinically caries involving cementum only cannot be diagnosed because cementum is only 16-60 microns thick near CEJ. When root caries is clinically diagnosed dentinal involvement has already occurred. Brown discoloration with softening of the root structure may be found.