So you got a dental filling, or restoration. Your tooth has been filled. What does that exactly mean? what has been pout in your tooth and why?
Let us start from the beginning. Why do we need a filing in the first place?
When your tooth gets decayed, the decay eats out your tooth structure. Teeth do not heal, so whatever tooth structure is gone, will never be replaced. Hence we need a material to replace it, or restore what has been lost, a restoration.
- Step one starts by getting rid of all the decay, and removing any weak tooth structure.
- Step two, is to condition the tooth to receive the final restoration. This however involves several
- Step three is packing the restoration, curing it, and polishing it.
The restoration materials used in dentistry are harmful to the pulp of the tooth. The pulp is a connective tissue structure that resides in the core of the tooth. The material can reach the pulp via seeping through canals present in the dentine of the tooth called dentinal tubules.
- The first step of conditioning the tooth involves protecting the pulp. This entails placing a protective layer to seal the dentinal tubules. This is usually achieved by using calcium hydroxide layer.
- Calcium hydroxide however can desolve by the resin used later to glue the final restoration. Hence a base layer made of Glass ionomer – contain a basic glass and an acidic polymer liquid, which set by an acid-base reaction. The polymer is an ionomer, containing a small proportion – some 5 to 10% – of substituted ionic groups. These allow it to be acid decomposable and clinically set readily.The glass filler is generally a calcium alumino fluorosilicate powder, which upon reaction with a polyalkenoic acid gives a glass polyalkenoate-glass residue set in an ionised polycarboxylate matrix. –
is used on top of the calcium hydroxide.
- An acid, 37% phosphoric acid, is used to chemically etch the enamel and make it more retentive.
- The resin (glue) is applied to the tooth structure.
- The final restoration, which is a filled resin called composite is packed as the final restoration. Composite is made up of a matrix made of BISGMA, UDMA, or semi-crystalline polyceram (PEX) with an inorganic filler, like silica.
Various materials are packed into your tooth to make up the final restoration.