STYROFOAM DENTAL IMPRESSION TRAYS FULL
STYROFOAM DENTAL IMPRESSION TRAYS REGISTRATION

Try not to “overseat” or push the tray too hard.This keeps a lot of the material from escaping toward the back of the throat. Seat the posterior portion of the tray first, followed by the anterior portion.Make sure the tray is centered over the teeth.Retract the patient’s cheek when sliding the tray into the patient’s mouth.Turn the tray slightly to insert a corner of the tray into the patient’s mouth.Position yourself for easier insertion of the tray and better control of the patient.For a maxillary impression, 3 scoops of powder and 3 measure lines of water are necessary. When mixing the material for a mandibular impression, generally 2 scoops of powder and 2 measure lines of water are required. The water-to-powder ratio for mixing alginate is 1 scoop of powder to 1 “measure line” of water. A plastic scoop is provided for dispensing the powder, and a plastic cylinder is supplied for measuring the water ( Figure 22-5). The material is available in two settings: normal set, which has a working time of 2 minutes and a setting time of up to minutes, and fast set, which has a working time of minutes and a setting time of 1 to 2 minutes.Īlginate is supplied as a powder, packaged in premeasured packages or in bulk canisters. This material has two physical phases that it goes through when setting: a sol (solution) phase, where the material is in a liquid or semiliquid form and a gel (solid) phase, where the material becomes semisolid.

Alginate consists of potassium alginate, which is derived from seaweed calcium sulfate trisodium phosphate diatomaceous earth zinc oxide and potassium titanium fluoride. A preliminary impression can be taken by the dentist or by the expanded-functions dental assistant.Īlginate is an irreversible hydrocolloid (“hydro” meaning water and “colloid” meaning a gelatinous substance) and is the material of choice when taking preliminary impressions. Preliminary impressions are used to create a reproduction of the teeth and surrounding tissues. (Courtesy 3M Dental Products, St Paul, Minnesota.) Preliminary Impressions There are three types of impressions that can be obtained ( Box 22-1):įigure 22-4 Example of a bite registration. When an impression is poured in stone or plaster to make a model, it creates a positive reproduction of the teeth and their surrounding structures. An impression is a negative reproduction of the teeth and their surrounding structures. Impression materials are selected because of their unique qualities that allow the dentist to get the most accurate reproduction of the tooth and surrounding tissues. F and G, From Bird DL, Robinson DS: Modern dental assisting, ed 10, St Louis, 2012, Saunders.) ( E, From Boyd LB: Dental instruments: a pocket guide, ed 4, St Louis, 2012, Saunders. G, Vacuum-formed custom tray, used for tooth whitening and for fabricating provisionals. F, Acrylic custom tray used to take final impressions for fixed and removable prostheses.

STYROFOAM DENTAL IMPRESSION TRAYS REGISTRATION

E, Triple tray used to take final impression and bite registration at the same time. D, Gauze tray used for bite registrations. C, Plastic perforated tray used for preliminary and final impressions. B, Metal water coolant tray used with reversible hydrocolloid impressions. A, Metal perforated tray used for preliminary impressions. Table 22-1 reviews the different types of trays available ( Figure 22-1).įigure 22-1 Types of stock trays.

STYROFOAM DENTAL IMPRESSION TRAYS FULL

Impression trays are supplied as quadrant trays, which cover half of the arch section trays, which are suited for the anterior teeth and full arch trays, which cover the complete arch. The type of tray selected for a procedure will depend on (1) the dentist’s preference and (2) what will provide the most accurate result for the type of impression material being used. Impression trays are designed for obtaining an accurate impression of the area required. The dental assistant is responsible for knowing the different types of impression materials used in the office, the setup for the procedure, the mixing of the material, and either assisting in the procedure or the actual taking of the impression. Because of the many uses of an impression, many types of impression materials are available. Impressions in dentistry are used for creating a model for diagnosing conditions, making custom trays, making a temporary crown, or for the laboratory technician to create a permanent indirect casting. In many dental procedures, an impression will be taken. 1 Pronounce, define, and spell the Key Terms.Ģ Describe the types of impression trays and their characteristics of use.ģ Discuss hydrocolloid impression materials and their uses, mixing techniques, and application.ĥ Discuss elastomeric impression materials and their uses, mixing techniques, and application.Ħ Describe the importance of a bite registration and its uses in a procedure.

Styrofoam dental impression trays