Restorative Dentistry Flashcards
7 cards from real NBDE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Restorative Dentistry flashcards as text
Which type of taper is recommended for full-crown preparations to balance retention and resistance form?
Answer: 6–10 degrees total convergence angle
A total occlusal convergence of 6–10 degrees provides adequate retention while allowing seating of the crown and appropriate resistance form.
A patient has a defective marginal ridge on an existing MOD amalgam. The MOST likely clinical consequence if left untreated is:
Answer: Loss of contact and food impaction leading to periodontal disease
A defective marginal ridge can collapse, eliminating the proximal contact and causing food impaction that leads to periodontal bone loss and caries.
The ADA Specification No. 1 for dental amalgam specifies maximum allowable dimensional change after setting. Which behavior is ACCEPTABLE?
Answer: Expansion of 20 μm/cm or less
ADA Specification No. 1 allows a maximum expansion of 20 μm/cm and a maximum contraction of 0 μm/cm (no net contraction permitted) for amalgam.
Bonding to enamel using phosphoric acid etching creates micro-tags by:
Answer: Selectively removing enamel rod cores or peripheries to create micro-porosities
Phosphoric acid selectively dissolves enamel rod cores or peripheries depending on the etching pattern, creating micro-porosities into which resin flows and polymerizes.
A full gold crown is being cemented with zinc phosphate. To minimize postoperative sensitivity, the dentist should:
Answer: Mix the cement on a chilled glass slab with prolonged spatulation to slow setting
Mixing zinc phosphate on a chilled slab and spatulating over a larger area slows the exothermic reaction, lowers the initial pH, and reduces pulpal irritation.
Which of the following is a contraindication for placing a porcelain-fused-to-metal crown on a maxillary first molar?
Answer: Deep overbite with limited interocclusal clearance
Insufficient occlusal clearance (deep overbite) prevents adequate reduction for the metal coping and overlying ceramic, risking restoration fracture.
Smear layer removal during dentin bonding is important primarily because it:
Answer: Allows resin monomers to infiltrate the underlying dentin for bonding
The smear layer is a physical barrier; removing or modifying it exposes collagen fibers and open tubules so resin can infiltrate and form a hybrid layer for adhesion.