What are the differences in denture design and materials?

Answer 1

We manufature dentures the difference is cost of material

The above answer is correct up to a point. The method of processing a denture has a great deal to do with the quality of a finished denture.

1. There is the injection technique of processing a denture and many say that a denture that is under constant injection while being processed will be the best fitting denture with the least amount dimensional change after processing because acrylic is injected in a closed flask system. The acrylic being under the constant pressure of injection will replace the acrylic that is lost while the denture acrylic is being cured during processing. Acrylic shrinks while it is being processed and depending upon the injection technique the theory is sound. Where it would fall apart is how good was the impression of the persons mouth in the first place. Impression materials shrink or expand depending upon what is done to them and how they are stored while being sent to the lab for the model to be poured up. Who actually took the impression and did they know what they were doing?

2. There is the method of packing a denture in the split flask, lost wax technique that has been around for quite sometime and is still how most dentures are processed. It has been around for a long time because it works.

Both of these techniques work quite well and this is where the materials that are used come into play. With the advent of hardened acrylic teeth there are a number of lines of teeth that are considered premium teeth, Dentsply's IPN teeth, Ivoclar Blue Line teeth, Lincoln Dental Image Tooth line and Vita's Physiodens to name a few. There are many economy teeth that are to numerous to mention except to say that generally you get what you pay for and economy teeth wear down much quicker than what most dental professionals consider a premium tooth. The other material that comes into play is the pink acrylic that the teeth are set in. This is considered the foundation of the whole denture structure and as in any structure the stronger the foundation the longer the structure will last. Three parts Polymethyl methacrylate (PMMA) powder to One part Methyl methacrylate (MMA) liquid has been the basis of these pink acrylics since the 1930's, in the early 1970's there was an advancement of impact modified powders that strengthened the impact resistance (made the acrylic harder to fracture) of heat cured processed denture acrylic (split flask, lost wax technique, packed dentures). In the 21st century there are a number of impact modified acrylics.

3. Auto-Polymer Acrylics used in the Pour or Fluid Resin system dentures. These acrylics have accelerators usually in the MMA, that quickly polymerize the denture acrylic when cured in a pressure vessel with warm water. The pressure vessel is only able to generate 15 to 25 PSI and in some of the newer pressure vessels close to 50 PSI. Not enough compression to make an actual Hi-Impact resistant denture like in the Injection Technique or the Packing Technique where thousand of pounds of pressure is used. Because of the amount of liquid used is larger there is also more shrinkage along with the accelerators used in the liquids there tends to be issues with color stability. However these dentures have a place in the industry in that they can be made quickly and easily finished without the mess made in the other techniques.

All of the above is just a brief explanation of the materials and techniques used in processing a denture. A good impression of the mouth is still required to make the denture fit properly and there are many theories as to the design of the denture which only a well educated dentist could expound upon.