'Caries' is Latin for 'rot' or 'rotten'. Dental caries is the term used to describe rotten teeth or tooth decay which results in cavities or holes in the teeth. It is an extremely destructive disease and occurs more often in children and young adults. It is the most important cause of tooth loss in younger people.
The causes of tooth decay can be described by the interaction of three factors. These factors are specific bacteria (found in plaque) sugar and a susceptible tooth surface. The process by which the three interact is described below:
A pellicle or coating on the teeth starts to form as soon as you put down your toothbrush. This coating contains proteins from the saliva and ﾔhostsﾔ bacteria which attach to the pellicle. This is the beginning of plaque. Sugars such as glucose fructose maltose and lactose are found in all carbohydrate foods. Of these sugars glucose and fructose are more destructive than that of maltose.
The bacteria in the plaque use sugar as a source of energy. The bacteria digest the sugar and a by-product is excreted. This by-product is extremely acidic and causes a drop in the mouth's pH (acid value). In a healthy mouth the pH is around 6.2 to 7.0. A pH of 7 is neutral. When the pH is less than 5.5 the tooth is in an acidic environment and starts to demineralise (lose calcium and minerals from the enamel). As the enamel loses its minerals it starts to break down. This is the start of a cavity.
Bacteria thrive on sugar and an acidic environment leads to more bacteria. It is a vicious circle that creates an environment that becomes increasingly destructive with time.
The sticky acid excreted by the bacteria is excreted right against the surface of the tooth and immediately starts attacking the enamel. Teeth with ﾔnooks and cranniesﾔ will trap more food than those with smoother surfaces. Teeth that have just emerged such as those of children and young adults have enamel that is not yet very strong and are thus highly susceptible to acid attack.
The first visible symptom of this condition is a white spot on the tooth - the area of enamel being demineralised by the acid. Once the demineralisation has progressed to the inner part of the tooth (dentine) the damage is permanent and a cavity can be seen. This cavity will deepen until it eventually reaches the pulp and infects the health of the nerve and blood vessels. Other major symptoms of caries include visible pits in the teeth discoloration of teeth or a filling that has fallen out.
Diagnosis of tooth decay is usually the result of a dental examination. When the dentist examines the surface of a tooth for possible caries an explorer is used to follow around the grooves and if it becomes stuck it usually means a cavity has formed. Newer techniques such as the use of staining dye are helpful in detecting caries under old amalgam fillings when these are removed.
If your dentist discovers a cavity then treatment is necessary to stop any further damage. Some of the more common treatments include simply be treating the areas with high concentrations of fluoride (if the damage is caught early) resulting in the arrest of the caries and remineralised tooth enamel. Fillings can be used to repair the damage caused by caries. Crowns are used if decay is extensive and In extreme cases root canal treatment is needed. Sometime the damage is too severe and the tooth is removed and replaced with an implant denture or bridge.
Oral hygiene is the primary prevention against tooth decay. This consists of personal care (proper brushing at least twice a day and flossing at least daily) and professional care (regular dental examination and cleaning every 6 months). The use of dental sealants is a good means of cavity prevention. Sealants are thin plastic-like coating applied to the chewing surfaces of the molars. This coating prevents the accumulation of plaque in the deep grooves on these vulnerable surfaces. Sealants are usually applied on the teeth of children shortly after the molars erupt. Older people may also benefit from the use of tooth sealants. Fluoride is also often recommended to protect against tooth decay and using a toothpaste with a good amount of fluoride is essential.