The impression trays serve as a carrier for the material used in creating the mold of teeth and adjacent structures. There are several types depending on the size and shape of the jaw of the patient.
The Impression Trays are of 2 main types:
1) Dentulous: These are trays which are used to take impressions of people with teeth or of a dentulous mouth.
2) Edentulous: These are trays which are used to take impressions in an edentulous mouth or a patient without teeth.
The are again divided into two types, based on the presence of perforations in it:
1) Perforated: There are small perforations or holes in the tray.
2) Non-Perforated: There are no perforations in the trays as they are used to carry impression materials which are not rigid Ex. Alginate.