Dental caries; Definition, Etiology, Causes, Risk Factors, Treatment.

DEFINITION

Is a localized progressive irreversible bacteria damage to an expose tooth in the oral cavity, leading to the demineralization of tooth by acid and eventually cavity formation.

The early manifestation of the caries process is a small patch of demineralised (softened) enamel at the tooth surface, often hidden from sight in the fissures (grooves) of teeth or in between the teeth. The destruction spreads into the softer, sensitive part of the tooth beneath the enamel (dentine). The weakened enamel then collapses to form a cavity and the tooth is progressively destroyed. Caries can also attack the roots of teeth should they become exposed by gum recession. This is more common in older adults.

ETIOLOGY/CAUSES

Dental caries is caused by the effect (action) of acids on the enamel surface. The acid is produced when sugars in foods or drinks react with bacteria present in the dental biofilm (plaque) on the tooth surface. The acid produced leads to a loss of calcium and phosphate from the enamel; this process is called demineralisation.

Saliva acts to dilute and neutralise the acid which causes enamel demineralisation and is an important natural defence against caries. Aside from buffering plaque acids and halting the demineralisation of enamel, saliva provides a reservoir of minerals adjacent to the enamel from which it can remineralise and “heal” once the acids have been neutralised. However, when saliva flow is disturted like in the case of xerostomia, the oral environmental becomes more favourable to the bacteria producing acids.

The enamel demineralises and remineralises many times during the course of a day. It is when this balance is upset and demineralisation exceeds remineralisation that caries progresses. When demineralisation occurs frequently and exceeds remineralisation over many months, there is a breakdown of the enamel surface leading to a cavity. Cavities, even in children who do not yet have their permanent teeth, can have serious and lasting complications such as pain, tooth abscess, tooth loss, broken teeth, chewing problems and serious infection.

SIGNS AND SYMPTOMS

• Toothache, spontaneous pain or pain that occurs without any apparent cause
• Tooth sensitivity
• Mild to sharp pain when eating or drinking something sweet, hot or cold
•  Visible holes or pits in your teeth
• Brown, black or white staining on any surface of a tooth
• Pain when you bite down

DIAGNOSIS

• The use of visual sight
• The use of instruments such as dental probe
• The use of radiograph (x-ray)

RISK FACTORS

• Tooth Anatomy. Decay most often occurs in your back teeth (molars and premolars). These teeth have lots of grooves, pits and crannies, and multiple roots that can collect food particles. As a result, they're harder to keep clean than your smoother, easy-to-reach front teeth.

• Some foods and drinks. Foods that cling to your teeth for a long time — such as milk, ice cream, honey, sugar, soda, dried fruit, cake, cookies, hard candy and mints, dry cereal, and chips — are more likely to cause decay than foods that are easily washed away by saliva.

• Frequent snacks consumption. When you steadily snack or sip sugary drinks, you give mouth bacteria more fuel to produce acids that attack your teeth and wear them down. And sipping soda or other acidic drinks throughout the day helps create a continual acid bath over your teeth.

• Nocturnal breast feeding. When babies are given bedtime bottles filled with milk, formula, juice or other sugar-containing liquids, these beverages remain on their teeth for hours while they sleep, feeding decay-causing bacteria. This damage is often called baby bottle tooth decay. Similar damage can occur when toddlers wander around drinking from a sippy cup filled with these beverages.
  
• Poor oral hygiene. If you don't clean your teeth soon after eating and drinking, plaque forms quickly and the first stages of decay can begin.

• Lack or inadequate fluoride sources. Fluoride, a naturally occurring mineral, helps prevent cavities and can even reverse the earliest stages of tooth damage. Because of its benefits for teeth, fluoride is added to many public water supplies. It's also a common ingredient in toothpaste and mouth rinses. But bottled water usually does not contain fluoride.
  
• Age. In the United States, cavities are common in very young children and teenagers. Older adults also are at higher risk. Over time, teeth can wear down and gums may recede, making teeth more vulnerable to root decay. Older adults also may use more medications that reduce saliva flow, increasing the risk of tooth decay.
  

• Dry mouth. Dry mouth is caused by a lack of saliva, which helps prevent tooth decay by washing away food and plaque from your teeth. Substances found in saliva also help counter the acid produced by bacteria. Certain medications, some medical conditions, radiation to your head or neck, or certain chemotherapy drugs can increase your risk of cavities by reducing saliva production.

TREATMENT

The main treatment option for a tooth cavity is to drill out the decay and put in a filling (restoration) made from various materials (e.g., composite resins, amalgam, porcelain).Extensive 

tooth decay may necessitate a crown, root canal treatment or even extraction of the tooth. Extraction seems to be the last option because dentistry doen not encourage it. Also the cost of other treatment options, makes some patient choose extraction.

In the 1990s, there was strong controversy regarding the possible damage to health from the use of mercury amalgam material to fill cavities caused by decay. Extensive research has shown that there is no valid scientific evidence to support a link between the presence of amalgam fillings in the mouth and systemic disease. A safety review (2008) conducted by the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) of the European Commission confirmed that both mercury amalgam and alternative filling materials such as composite resins, glass ionomer cements, ceramics and gold alloys are safe to use for restoring teeth. Nonetheless the Minamata Convention on Mercury (2013) includes agreement to a global phase-down of the use of dental fillings containing mercury amalgam taking into account the domestic circumstances of individual countries. The need to ensure environmentally sound storage and final disposal of the product was also finalized.