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In countries that do not have the same level of education and awareness about oral hygiene seen in developed nations, it is quite common to see people with missing teeth. In fact, the primary reason to seek dental care is for relief from pain. The cost of the treatment also becomes a big factor in these countries and so a fixed prostheses remain out of bounds for most people. Of course, the cost is also a concern in developed nations where the cost dental care is prohibitively high.
For these situations and others where poor medical health of the patient or a lack of healthy supporting teeth make removable prosthesis the only option, dentists rely on partial dentures to treat patients.
Drawbacks Of Traditional Dentures
Traditional acrylic dentures were made out of material that was very affordable and easy to fabricate, however, quite prone to breakage. This meant that a large amount of bulk had to be maintained in the denture base to give it some amount of strength and resistance. This is obviously not the most comfortable option for patients.
They also do not have any "give" to them, and thus transfer all the shear stresses to the supporting teeth. The amount of force being transferred is well within the range that a healthy tooth or set of teeth can bear but a compromised tooth may not be able to withstand it.
Lastly, the metal clasps that are used to provide retention and support to the denture are quite uncomfortable for the patient and unsightly to look at.
The need to improve upon the kind of removable prosthesis in vogue without compromising the affordability of the material saw two brothers, Arpad and Tibor Nagy, experiment with polymers and come up with Valplast as the first flexible denture material. This material has some immense structural advantages.
Elasticity And Flexibility
The biggest advantage that dentures made from this material have over conventional dentures is that this material has a much higher modulus of elasticity. When a denture is in the mouth, it is frequently subjected to heavier forces on one side. These forces have a tendency to lift the dentures from their position on the other side. The more rigid the material, the more likely it is to lift. Thus, a set of dentures made from flexible material is able to absorb some of the forces by flexing a little and not being lifted up.
Flexible dentures are much more effective at distributing stress evenly and translating the least amount to the supporting teeth. It is not even easy to estimate the amount of grief this will save patients over a few years of use. Doctors are used to seeing patients who are wearing dentures come in after a few months or years complaining that the teeth supporting the denture have become mobile or have started to hurt.
The credit once again goes to the inherent properties of the material, although the overall design of the denture also plays a role.