What are fillings and how do they work?

What exactly is a filling? And how do they work? Fillings are a treatment for cavities found at your local dentist Stevenage but to really understand what fillings do and how they resolve cavities, you need to know how cavities come about in the first place and what dental decay is.

Dental decay

Decay starts with a small number of bacteria establishing themselves in a sheltered spot in the tooth where they are unlikely to be disturbed. It could be between teeth or in the canyon of molars. The bacteria then multiply by consuming sugars found in saliva but when they digest anaerobically, they produce lactic acid as a by-product. This acid attacks the tooth upon which they live and creates small crevices in the tooth. This provides additional shelter for the bacteria and helps them grow in number. Eventually, this process repeats itself enough for them to bore completely through the enamel layer and into the dentin underneath.

So, cavities are likely to occur in places that are difficult to spot and they have few symptoms until they reach the nerve. It’s usually only by a dental examination that you find out if you have cavities and whether the treatment is necessary.

Why are fillings done?

When decay has set in, there is a brief period just between, when the colony has not breached the enamel layer. These holes can be remineralised where the lost calcium phosphate is replaced either with dietary calcium or fluoride absorbed directly from the fluoride in toothpaste. These fluorides form a less chemically vulnerable component of the enamel, which will restore the volume of the enamel layer.

If the decay is significant enough to reach through the enamel layer and has attacked the dentine, a filling is necessary, as remineralisation is no longer possible and the active bacteria is too deep into the tooth to be removed by brushing. In addition to this, dentine is far softer and can be rapidly broken down, so the rate of decay will increase dramatically.

dentist with her assistant

How are fillings carried out?

The drilling stage of filling a tooth is the longest and most important. The bacteria which have been causing the decay will have found their way deep into the tooth and unless they are totally removed, they will continue to burrow into the tooth. After the drilling has begun, often resulting in a loss of structural stability, your dental team will establish which type of filling is suitable and will continue to clean the cavity using the drill.

After completely cleaning out the cavity, the filling can begin. Traditional metal amalgam fillings start with the production of a metal putty; the ingredients are mixed and the putty is applied usually through an application gun deep into the base of the drilled cavity and gradually filled until the surface is reached. In a few minutes, the amalgam will set hard.

Composite fillings use ceramic glass sealed into place with UV cured resin. They are applied in layers; the resin is injected through a syringe and then has to be cured with a brief exposure to a UV lamp. After which, a second and third layer can be built up until the tooth has been filled solidly and completely set.

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