[An attempt of introduction to prosthodontics of a non-contact device for measuring small configurations. Determining configurational changes during the individual steps of denture fabrication].

Denture fabrication involves a number of complex operations that have an effect on reproduction accuracy during each step of the process. Traditionally, metal patterns act as the standard for the mechanical properties of the main materials used in denture making. This means that doubts still remain in cases where the mucous membrane, with its complex configurations, is the object of investigation. The non-contact measuring instrument using laser light (known hereafter as "measuring instrument") enabled measuring small configurations. The measuring instrument enabled measurement of physical configurations that up to now were considered impossible to measure. The fabrication process up to creation of a denture base with the mucous membrane as the basic pattern was divided into four steps for measurement: mucous membrane, impression material, plaster and resin. The measuring device simultaneously carried out qualitative and quantitative analysis in three dimensions for all steps. Processing of test materials was unnecessary so that measurements could be accomplished in a very short time. Measurements revealed a variety of features, including those that are not affected by the physical properties of the materials for measurement. It was also possible to systematically investigate the various changes that take place during denture fabrication with the mucous membrane acting as the basic pattern. The following results were obtained: 1. The experiment confirmed possible application in dentistry of a non-contact device that uses laser light to measure extremely small configurations. 2. Results hint at the possibility of quantitative measurement of objects that cannot be directly measured with conventional methods. 3. During fabrication of dentures, it is very easy for changes in the total configuration to occur when taking impressions. Minute changes in the configuration occur on the surface when taking the plaster cast. During the final stage of the resin base, the tiny configurations became flat and resembled the configuration of the impression more than the original configuration of the mucous membrane.