What are they?
A crown completely covers a weak tooth above the gum line and protects it. Crowns are made of metal or porcelain, or porcelain with metal inside for strength. Only metal crowns are considered clinically necessary on molars by the NHS.
An inlay covers a tooth that may have a lot of tooth substance missing because of decay, a fracture or a large filling that was previously present. It does not cover the whole tooth. Instead of a large filling the dentist may advise an inlay. Inlays are made of metal, gold, porcelain or composite (white plastic material). Only metal inlays would be considered clinically necessary on the NHS.
What will NHS Dentist do?
- They will normally give you an injection to numb the area. As a general rule you should not eat or drink hot drinks until the injection has worn off.
- They will shape the tooth so that, with the crown/inlay, it will be the same size as a normal tooth. Your natural tooth will be considerably reduced in size and shape.
- Preparation time will depend on how damaged the tooth is and whether it needs to be built up with a filling first.
- The tooth might have to be root-filled first – this is sometimes called ‘removing the nerve’. A crown is sometimes held in place by a peg/post in the root canal if a lot of the tooth is missing.
- Your dentist will use a soft, mouldable material to make an exact ‘impression’ of the tooth that is to be crowned (or have an inlay) and the nearby teeth. A dental technician uses an impression to make the crown/inlay the exact height and size needed.
- A thin cord may be used to hold the gum away from the tooth so that the impression is accurate round the edges.
- A temporary crown made of plastic, acrylic or metal is put over the tooth until the crown is made. You can chew on a temporary crown but it will not be as strong as the finished one and may come off as it is fixed on lightly so as not to damage your tooth when we have to take it off. *You must return to have the temporary recemented. This is very important to ensure the crown will fit.
- A temporary filling will be put on the tooth due to have an inlay. A temporary filling is not as strong as the finished inlay and it may come off. *Please see above.
- If you do not make and/or keep an appointment for the fitting of your crown/inlay within a reasonable period of time (@4 weeks), no guarantee can be given that the crown/inlay will fit. A course of treatment will be closed within @ 2months and a new course of treatment will be charged in full.
- When the crown/inlay is fitted, your dentist will make small adjustments to make sure you can bite comfortably. The crown/inlay is tried on first so you can agree to it and then glued into place.
What are the benefits?
- A crown is strong and can look and feel exactly like a natural tooth. The colour and shape can be matched as closely as possible to your own teeth.
- Inlays are stronger than fillings.
- Inlays are more aesthetically pleasing than amalgam fillings.
- Depending on the strength of the tooth underneath, a crown can last for many years if you look after your mouth and teeth and the crown is not accidentally damaged.
- Crowns can also improve the appearance of misshapen or discoloured teeth.
What are the disadvantages?
- Sensitivity to extreme temperatures can be expected from newly crowned vital teeth. If it persists then the tooth may need root canal treatment.
- Gums may recede around the crown margins revealing a thin metal line. Good oral hygiene reduces the progress of this problem. Once the tooth preparation is done on your natural tooth, you will never be able to go without a crown.
It is your choice whether you wish to undertake this procedure.