Impression trays are devices used in dentistry to hold the materials utilized in the production of dental impressions. Dental impressions are molds of the teeth which can be used in the fabrication of crowns, the production of dentures, and in many other dental procedures. In addition, impressions are taken by forensic dentists for the purpose of comparison, as for instance when dental impressions are made of an unknown victim to assist with identification.
Numerous medical supply companies make impression trays. Many produce disposable versions which are designed for single use. With a disposable impression tray, a dentist can keep the tray sealed in a sterile package until it is ready for use and discard it after an impressions is made. By contrast, reusable trays need to be cleaned and sterilized between uses, and can add work to a busy dental practice.
The shape and size of the tray varies. Multiple sizes are made to accommodate a range of mouth sizes, and the shape may be varied to address the need for different types of impressions. For example, a dentist might only need an impression of the teeth on the right side of the jaw, in which case a partial impression tray could be used. Designs are also adjusted to meet patient comfort needs, as the process of taking an impression is often uncomfortable and patients may gag unless the tray is designed and positioned properly.
Impression trays can be used for more than holding the material used to make dental casts. They are also suitable for teeth whitening or bleaching procedures, as the design of an impression tray is intended to contain a liquid while the tray is positioned in the patient's mouth. Fluoride treatments can also be done with impression trays. For certain types of dental procedures, medical supply companies make packaged kits which include all of the necessary supplies, from impression trays to medicated treatments.
Dental casting materials are designed to set quickly, but the setting times can be variable and for treatments like bleaching it may be necessary to keep the tray in the mouth for an extended period of time. When a dentist needs to use an impression tray, patients may want to ask how long the tray will need to be held in the mouth so that they will have an idea ahead of time. If a patient has a strong gag reflex or has difficulty with dental procedures, there may be alternative impression mediums available which could set more quickly and minimize the length of time the tray needs to be held in the mouth.