What is caries?

Caries is the clinical term used to describe dentinal tissue infected by microorganisms, and is the cause of the majority of work carried out within a dental practice. It is sometimes referred to as tooth decay or a “cavity”.

Teeth are made up of various parts, but the part we see in the mouth – the crown – is made up of mainly dentine, enamel and the pulp. Enamel is an inorganic structure which is formed by ameloblasts and is the hardest substance in the human body. Ameloblasts are specialised cells which are active only to lay down enamel during tooth formation in pregnancy and then break down before the teeth even erupt in the mouth. This is why caries and prevention of caries is still the primary concern within dentistry today because once enamel has been destroyed it cannot be regenerated.

Dentine is an organic structure meaning it contains living cells. This is why we often become aware of temperature or acidic changes if the enamel of our teeth has been broken down exposing the underlying dentinal structure. Dentine is a tubular structure and is the only tissue separating the pulp from the enamel

So what causes dental caries?

Caries is caused when the structure of the enamel is damaged exposing the dentine underneath. The most common reason for this is acids produced by bacteria utilising the food we leave on and between our teeth. Bacteria in our mouths are essential and are part of our digestive system – we need them! When we neglect to clean our teeth, these bacteria feed on the food we leave behind and produce acids as a by-product, which demineralises the crystalline structure of enamel. Remineralisation can occur, but only if we allow our saliva to reach these areas. If remineralisation does not, or cannot, occur bacteria will then colonise the dentine and caries develops. (See https://keithdental.co.uk/acid-erosion/ for more information)

Once the protective barrier of the enamel is breached, bacteria populate the defect and utilise the dentinal tubules to get closer to the pulp in the centre of the tooth causing pulpitis (inflammation of the pulp).

Pulpitis can be either reversible or irreversible depending on the severity of the caries and the stage at which intervention occurs. Severity of the problem usually directly equals the increase in cost of fixing the tooth; therefore prevention of caries is essential. If we can no longer repair a tooth and stop the caries developing further, the only remaining options are root canal treatment or extraction. (See https://keithdental.co.uk/misconceptions-regarding-root-canal-treatments/ for more information).

Routine bitewing radiographs taken of 15 year old patient. Demineralisations can be seen outlined by blue; caries can be seen outlined by yellow. Each area in blue has the potential to become caries.


There are many ways in which we can prevent caries such as:

1. Keeping regular check-ups and hygiene visits

2. Regular interdental cleaning

3. Routine dental radiographs

4. Fissure sealants for all newly-erupted permanent teeth

When we keep regular dental check-ups, our dentists keep records of areas in our mouths that could potentially become problems later on. They get to know what is “normal” for each individual patient and so can spot any issues early. Hygienists encourage good oral hygiene habits and remove calculus deposits on/between our teeth which make interdental cleaning more difficult. These deposits can act as “stagnation areas” for food and bacteria which could develop into caries.

There are various products available which we can use to clean between our teeth but the most commonly used ones are dental floss/tape, TePe brushes and floss picks. When we remove the food from between our teeth before brushing with fluoride-containing toothpaste, we reduce our risk of caries significantly.

During your routine dental check-up, your dentist or nurse may take radiographs. We take these regularly to check for caries, to check bone levels and to ascertain the integrity of existing restorations. (See https://keithdental.co.uk/radiographs-as-a-diagnostic-tool/ for more information).

It is also important to have something called a fissure sealant done on all newly erupted posterior teeth. The pre-molar and molar teeth have what we call pits and fissures on the chewing surfaces, and sometimes these fissures do not close completely during formation. Therefore your dentist or hygienist may do a small sealant restoration on these teeth when they come into the mouth to prevent food and bacteria getting into the fissures and causing caries.

Prevention is the best way to keep our teeth and gums healthy and in doing so we keep ourselves healthy too!



Written by Miss Faye Law

Senior Dental Nurse at The Keith Dental Practice


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