KTR Dental

Accurate Impression

A recent study in the Journal of Prosthetic Dentistry reveals that over 80% of impressions sent to dental labs had OBVIOUS deficiencies. There were probably more that were not obviously defective but were still distorted. A stiff custom tray with about 2mm space to the prepared tooth surfaces is the most reliable way to avoid the vast majority of potential deficiencies. An easy way to accomplish this is to take a preop impression of the area and pour up in RapidSet™. Then vacuum-form a .08" thick rubbery clear "mouthguard" material. Cut off the extra material and then vacuum-form a .10" stiff "surgical tray" over the rubbery material. The excess material is cut off, the rubbery material is pulled out and wax stops are placed into the tray. The RapidSet™ model has the advantage of setting fast and the vacuum-forming procedure is more easily accomplished with it.

A very good way to provide the accuracy of a custom tray with the convenience of “stock” trays is to use a short stiff vacuum-formed tray that extends to adjacent teeth just beyond the prepared teeth area. This tray is seated first and a stock tray is placed over it to include it and the other teeth in the arch.