Dental impression trays are made of a thin metal sheet that holds together an inner plastic tray. The function of dental impression trays is to keep the patient’s mouth open and hold it in one position during certain procedures such as taking X-rays and teeth cleaning.
Dental impression tray help dentists take diagnostic images, which can reveal information about oral health problems, by keeping the tongue stationary while X-ray equipment takes pictures of otherwise difficult-to-see areas of the teeth, jaw, or skull. Impressions taken with dental impression trays are used for crowns, implants, bridges, partial dentures, so they need to fit comfortably and accurately.
Types of Dental Impression Trays
- Metal trays are typically used to take an impression for simple crowns, but they are very stiff and require a larger bite block to hold the mouth open. Although metal trays tend to be less expensive than PVS or resin models, they can warp easily with excessive heat (and thus increase in size) and provide only one-time usage; metal impression trays cannot be re-sterilized after use.
- Self-cured resins are made of plastic materials that allow for enhanced visibility during the impression process due to their translucency. These trays tend to fit more accurately than metal trays because self-cure resin material is relatively soft compared with the harder metal alloys; this allows them to more closely conform to the shape of the teeth. In addition, they can be re-sterilized and reused multiple times.
- PVS (plastic vinyl siloxane) is a proprietary material that combines the best qualities of self-cure resin and metal trays: It provides great visibility and accurate fit in most cases with only one-time usage; however, it is more expensive than metal or self-cure resin models due to its enhanced durability and sealing abilities.
Are dental impression trays hygienic?
According to Dentopia, yes, dental impression trays are hygienic. They consist of two parts: the metal shell and the inner plastic tray, so they can be separated for thorough cleaning between patients using either a special detergent or alcohol wipes
Precautions to take during dental impression tray fitting
- Dental impression trays should only be used once because they cannot easily accommodate changes in tooth position and can warp under heat and pressure (heating them before use helps decrease their stiffness).
- Always moisten dental impression trays prior to inserting them into the patient’s mouth for improved comfort and easier removal; however, make sure that you do not exceed recommended time limits during moistening as this may cause leaking of saliva from between the
Choosing Metal Dental Impression Trays
This type of impression tray is made of stainless steel or nickel-plated brass, metal trays offer rigidity but can be uncomfortable for patients. For that reason, they’re used mostly in laboratory situations where aesthetics aren’t as important because the tray will be covered by other materials. Metal trays also contain an inner plastic section to help it maintain their shape during use.
The biggest drawback is that the material isn’t soft enough to mold well around the mouth; this means it may not fit well, potentially causing leakage of the impression. A common solution is to use a metal tray on top of an adhesive denture tablet, which provides the advantages of the metal material without rigidity.