A complete prosthesis or denture replaces the natural teeth when they have been lost through caries or periodontitis. Dentistry distinguishes between complete dentures and partial dentures such as plate and frame models. It has been estimated that approximately three million people have dentures in the Netherlands.
A denture or FP (full prosthesis) basically sits on top of the oral tissue. Saliva adheres the plastic to the tissues and the mouth muscles may help to keep them in place. The hard, rigid plate must be able to function in a mouth, which in itself is constantly moving and flexible. This often causes problems; 25% of people with dentures are not happy with the result. It is often the lower jaw that causes the most complaints. The supporting surface of the toothless or edentate lower jaw is much smaller than that of the upper jaw.
Due to the increase in implantology it has become easier fix dentures in place. The FP is simply clicked in using push buttons or a bar. This can be quite costly, but is covered by most insurers under certain conditions. In some cases, it is also possible to use one’s own canines or false teeth if they have not been lost. This type of denture is also called a ‘click bite’.
A denture is not simply picked off the shelf or ready made. A number of steps are involved. enabling The dental technician needs enough information from the dentist to be able to model the dentures in wax and then reproduce them in plastic. Of course, we can also fix your old dentures (relining and rebasing). This means they will be good for years to come.
Dentures are made as follows
To make the dentures, the dentist first makes an initial impression (anatomical impression) cast with stiff alginate. Usually, the impression consists only of the teeth, but now we also include the section of the mouth where the jaw meets the cheek. A plaster cast model is made of this impression in the dental laboratory, and a unique to the patient model is produced. With this model, tailored exactly to the patient’s own mouth, a second impression is carried out.
A so-called edge structure is added to the model. This is a layer of hard wax that marks the transitions between tissues more clearly and better indicates the muscle attachments. Under light pressure, a special impression material is used to create a highly detailed model for the final impression. This material is often an elastomer or silicon. The muscles are manipulated during hardening (or curing) of the second model, called muscle trimming, to imitate the most frequently used movements. This is the basis of the second model. This is the model from which the final dentures will be made.
Now the dental technician will make a bite plate. This will determine the position of the lower jaw in relation to the upper jaw.
The bite plates determine the position of the upper jaw. Wax is pressed into the bite plates. The dentist checks whether the wax in the upper denture is high enough (it is at this position that the new teeth will be placed) and the angle of the bite plate relates to the line between the pupils of the eye and the line between the ear canal and the nerve below the eye are correct. The middle line is marked on the wax.
The wax on the lower jaw bite plate is adjusted accordingly. The height must be correct because otherwise the ‘bite’ – the total distance between the lower jaw and upper jaw when closing the jaw – will be either too high or too low.
If the wax impressions are correct, they are used for the next stage. After this appointment, the plaster cast models are placed in an artificial jaw or articulator using the bite plates The dental technician can then produce the dentures in wax.
This is the first time the patient sees his/her new teeth. If everything is ok, the dentures will be finished off and then put into place. The dental technician makes a plaster mould around the wax model and the wax is burned out. The space created is then filled with plastic.
After curing or hardening, the dentures are smoothly off and placed in the patient’s mouth.
From now on, the real work begins for the patient: learning to eat, speak, and do a range of actions with the new prosthesis in place. The time necessary to get used to new dentures differs from patient to patient, but may take up to 3 months.
A prosthesis should be well maintained and regularly cleaned. Many dentists recommend taking the dentures out at night so that the tissue of the mouth can recover. In addition, the prosthesis can then be left in a bowl of water with a spoon of vinegar overnight.
There are also partial prostheses available, should some natural teeth still remain. These are less expensive, but have some less positive features meaning it may be better to have complete dentures instead.
If there are still natural teeth in the jaw, one can opt for a frame prosthesis.
A frame prosthesis or cast prosthesis is a set of dentures constructed by a dental technician.
This basic prosthesis is usually cast in a chromium-cobalt alloy.
- the major connector (the brace that rests on the palate of the upper jaw or against the teeth of the lower jaw)
- The minor connector (the connection between the main connector and the denture base)
- The clips (the clips must encircle the natural tooth by at least 180°)
- The occlusal contacts (lay on top of the teeth and attached to the clips. These prevent the dentures from sagging and causing damage).
- a frame prosthesis is stable and fits more tightly
- the frame prosthesis feels thinner and of higher quality
- a frame prosthesis is not supported by soft tissue but by the teeth themselves
- the frame prosthesis is not fixed onto the teeth except where the braces and clips are, in other words, less food gets caught in this type of denture.
- higher cost
- possible development of a metal allergy
- the clamps are sometimes visible (aesthetics)
- it is more difficult to add an extra tooth onto a frame prosthesis