Dental impression
A custom impression tray should fit and adapt well to the model and should maintain ____ mm of impression material between itself and the teeth.
2-3 mm
How many milliliters of water should be mixed with 100 grams of high-strength dental stone?
b. 19 to 24
Water should be running through a model trimmer:
when trimming.
A plastic matrix strip is contoured by pulling the matrix lengthwise over the:
a. rounded end of cotton pliers.
What impression material comes from seaweed and is commonly used to make preliminary dental impressions?
Alginate is derived from brown seaweed!
A trimmed maxillary model will be _____ at the anterior portion, and the mandibular model will be _____ at the anterior portion.
Select one:
pointed round
How should light-cured resin tray material be cured?
b. Off the model
What causes air bubbles in a model?
air trapped during mixing or pouring
For there to be a solid closure of margins on a posterior composite restoration, where should the prongs of the tension ring for the Palodent system be placed?
Buccal to the band and wedge
What dental material becomes warm as it hardens because of a chemical reaction?
What is dental stone or gypsum?
The setting reaction of gypsum releases heat.
A vacuum former is utilized to conform a sheet of which of the following types of resin materials to a diagnostic model?
. Thermoplastic
How should the patient bite when positioning the bite-fork during a face-bow registration?
bite gently and evenly into the registration material
Alginate impressions must be poured within _____ so that distortion does not occur.
b. 30 minutes
What is the material of choice for a universal matrix band?
a. Thin, flexible stainless steel
What small dental device helps recreate a tight contact between two teeth during a Class II composite restoration?
The ring helps separate teeth slightly to compensate for matrix thickness.
After fabrication, when can a self-cured resin custom tray be used?
d. After 24 hours
How will gypsum material be affected if additional powder is added after mixing has begun?
b. Weaker
Each of the following can be done to alleviate the gag reflex when taking alginate impressions except one. Which one is the EXCEPTION?
Have the patient sit upright with the head tilted backward.
Which matrix system used for Class II posterior restorations is the most common?
a. Tofflemire retainer and universal band
What impression material should be poured promptly because it can shrink or swell if stored improperly?
Alginate can lose water through syneresis or absorb water through imbibition.
Before constructing a light-cured tray, what would be painted on the model?
d. Separating medium
In minutes, how long should one wait before removing a model from an impression after pouring?
d. 45 to 60
How are alginate impressions removed from the mouth?
Use one quick, snap-out motion. after breaking the seal
Why is a matrix band contoured prior to placing the restorative material?
. To ensure that the final restoration will have proper contact with the adjacent tooth
What instrument is used in the dental lab to trim and shape a hardened gypsum model?
What is a model trim A model trimmer uses an abrasive wheel and water to shape casts