There are lots of ways a dentist can trim the cost of a removable denture, and I don’t want to disparage here the efforts of dentists who want to try to bring down the cost of dentures for those patients who have difficulty affording them. But for the benefit of those who are looking for a quality denture, let me explain here what a dentist can do to enhance that quality.
There are various grades of materials that can be used to make a denture.
In the selection of teeth, there are three basic types. Acrylic teeth are the cheapest and the easiest to work with, but they are soft and susceptible to wear and staining. Porcelain teeth are more expensive. They are stain resistant, very hard, and have excellent esthetics. They used to be the choice for premium teeth, but their drawback is that they tend to come loose from the denture base easily. With the development of composite technology, composite has become the material of choice for quality teeth. Not as hard or as stain resistant as porcelain, they are much more durable than acrylic and develop a secure bond to the denture base.
There are similar differences in the quality of the denture base. The base is almost always made of acrylic, but there are many grades of acrylic. Cheaper acrylics will tend to shrink and distort as they cure, compromising the accuracy of the fit.
There are large variations in what dental laboratories charge the dentist for a set of dentures. The dental technicians at more expensive laboratories will pay more attention to details and will produce a more lifelike and esthetic product. Also, cheaper labs will use the cheaper base materials and teeth as explained above.
The technique for making dentures as taught in dental school involves many steps, several of which can be skipped in an effort to economize.
For the most accurate replication of the dental arches, dentists will use a multiple-impression technique. A first impression with an inexpensive and easy impression material like alginate can be used to make a preliminary model of the arch. This model will then be used to make a custom tray specifically for the particular patient being treated. Some dentists skip this step by using specially constructed moldable trays and say that this produces results that are as good. The dentist will then go to a more expensive and more technique-sensitive material such as polyether or polyvinysiloxane. A second impression with a heavy-bodied version of this impression material can be used to record the peripheries of the arch, and then a final impression with a light-bodied wash will record all the detail. Dentists can use the first preliminary model to construct the denture, but accuracy will be sacrificed.
With no teeth present, the patient has lost all reference points for how far apart the upper jaw should be from the lower jaw. Still, there is an optimal distance. If the dentist uses a measurement that is too small, the patient will end up with a face that looks collapsed and saggy, and will be overclosed, straining the jaw muscles and causing complications with speech. Similarly, a measurement that is too large will open the bite and also be uncomfortable and cause speech problems. The dentist also has to determine how much of the upper front teeth will show when the patient smiles. All of this is usually obtained by constructing what are called wax rims on temporary acrylic bases and testing different vertical dimensions for comfort and function.
If these dimensions and the positions of the teeth are incorrect, it can cause difficulty in pronouncing certain letters. Some people with dentures can develop a lisp or a whistling sound as they speak, an embarrassing consequence of a poorly designed denture.
To check whether all the dimensions and the positions of the teeth are correct, the dentist will do a wax try-in of the denture. The laboratory technician takes over at this point and, using the positions marked by the dentist with the wax rims, will place the teeth in the wax on the temporary baseplate. These will be the actual teeth that will be incorporated into the denture. Trying in the teeth gives the patient an opportunity to evaluate the esthetics of the case as well as to check again the comfort of the vertical dimension. The dentist may also ask the patient to pronounce certain words to make sure that the patient’s speech sounds natural.
It isn’t considered advisable for the patient to take home this wax try-in. The wax used to hold the teeth is soft, so it is easy to knock the teeth out of position. One patient who was given this opportunity also found that drinking coffee melted the wax and caused an awful mess.
During the wax try-in, the dentist will also make a final check of the bite to make sure it is balanced. This is a critical part of the denture construction, and the dentist will often used a sophisticated articulator instrument to replicate all the movements of the jaw in the laboratory. At the time of the construction of the wax rims, measurements of the positions of the jaw joints on either side and their relationship to other facial features will be made, and those measurements will be transferred to the articulator. The bite needs to be carefully calibrated because if it is uneven at all, it will create tipping forces when the patient chews, making chewing more difficult and possibly tending to dislodge the denture.
With all of this care, the dentist can make a set of dentures that will look natural, will be durable, and will be comfortable. It is unrealistic, however, for the false teeth of a removable denture to function like natural teeth. The upper denture will function the most naturally because, while it isn’t solidly anchored in the jawbone as teeth are, it is held in place by suction and its movement is somewhat limited. The lower denture, however, will float around somewhat, and the patient will have to learn how to control it with the cheeks and tongue. If the patient wants to replicate the feel and function of natural teeth, anchoring the denture with dental implants is the way to go.