Dent 1100: Section 3 Review Questions

Question 1

What is the purpose of a custom tray?

Answer 1

It enables a dentist to make a more accurate and detailed impression that is possible with stock trays.

Question 2

What type of impression material is used with a perforated or rim-lock tray?

Answer 2

Alginate, water cooled trays for agar-agar hydrocolloid

Question 3

What are the disadvantages of an impression compound custom tray?

Answer 3

1. The single appointment usually lasts longer than the combined time of the two appointments required for preliminary and final impression utilizing resin custom trays
2. Bulkier than trays made out of resin material, and are more difficult to handle.

Question 4

Describe the construction steps of a custom tray made of “dead soft” material on a maxillary cast

Answer 4

The outline starts at the labial frenum, rises over the incisor and canine regions, down around the facial frenum (which may be indistinguishable as is the one on the cast in the illustration) up over the molar region around the posterior corner of the impression and through the hamular notch. It then crosses the posterior portion of the cast through the fovea palatina (usually two small depressions in the posterior portion of the cast). The hamular notch is the depression behind the maxillary tuberosity and the impression tray must cover this area.

Question 5

Name four techniques for constructing a custom tray and indicate the most common techniques.

Answer 5

1. Wax spacers

2. L-shape handle