Dental Materials & Equipment Maintenance Flashcards
7 cards from real EFDA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Dental Materials & Equipment Maintenance flashcards as text
Which curing light intensity is considered the minimum for adequate polymerization of composite resin?
Answer: 400 mW/cm²
A minimum irradiance of 400 mW/cm² is generally required to achieve adequate polymerization depth and degree of conversion in composite resins.
What is the function of a matrix band during a Class II composite restoration?
Answer: Provide a temporary wall to replace the missing proximal surface during condensation
A matrix band recreates the proximal wall of the tooth, allowing the composite to be condensed against it and achieving proper contour and contact.
Which solvent is recommended to clean composite resin that has not yet been light-cured from instruments?
Answer: Alcohol (isopropyl)
Isopropyl alcohol effectively dissolves uncured composite resin from instruments without damaging them.
When using an ultrasonic scaler, the water spray serves which critical function?
Answer: Cool the tip and lavage the surgical site to prevent thermal damage
The water coolant prevents heat buildup from ultrasonic vibration that could damage the pulp, and flushes debris from the subgingival area.
What is a key reason why dental impression materials should be poured promptly after removal from the mouth?
Answer: Syneresis or imbibition can alter the dimensional accuracy of the impression
Alginate and hydrocolloid impressions undergo syneresis (shrinkage) or imbibition (expansion) if not poured immediately, causing dimensional inaccuracies in the resulting model.
Which action is required when a sterilization pouch's chemical indicator does NOT change color after a cycle?
Answer: Re-run the load and quarantine items until biological indicator results are confirmed
A failed chemical indicator suggests the sterilization parameters were not met; the load must be re-processed and quarantined pending biological indicator confirmation.
What effect does increased spatulation time have on zinc phosphate cement?
Answer: Increases working time by dissipating heat on the cool slab
Mixing zinc phosphate cement over a large, cool glass slab with extended spatulation dissipates heat and slows the acid-base reaction, thereby increasing working time.