Bases, Liners, and Matrices Flashcards

A sectional matrix system (e.g., Palodent) is preferred over the Tofflemire system for Class II composites because it:

Answer: Provides better proximal contact and contour

Sectional matrix systems produce tighter, more anatomically correct proximal contacts compared to the circumferential Tofflemire band.

Copal varnish is applied in a cavity preparation primarily to:

Answer: Seal dentinal tubules and reduce microleakage under amalgam

Copal varnish seals dentinal tubules to reduce microleakage and postoperative sensitivity under amalgam restorations.

Which matrix system would be MOST appropriate for restoring a severely broken-down molar with missing proximal and buccal walls?

Answer: Copper band or custom matrix

A copper band or custom-fabricated matrix is best for teeth with extensive wall loss that standard matrix systems cannot adequately contain.

What is the correct consistency of zinc phosphate base when mixed for use as a base (not a luting cement)?

Answer: Putty-like consistency that holds its shape

A base consistency for zinc phosphate is thick and putty-like, providing adequate bulk and resistance to compressive forces.

The purpose of a wooden or plastic wedge used with a matrix band is to:

Answer: Separate the teeth slightly and seal the gingival margin

The wedge separates the teeth to compensate for band thickness and seals the gingival margin to prevent material flash.

Glass ionomer cement used as a base is placed in which preparation zone?

Answer: The axial and pulpal floors over exposed dentin

Glass ionomer base is applied over exposed dentin on pulpal and axial floors where thermal and chemical protection is needed.

Which of the following best describes the 'sandwich technique' in restorative dentistry?

Answer: Using a glass ionomer base beneath a composite resin restoration

The sandwich technique uses a glass ionomer base bonded to dentin topped with composite resin, combining fluoride release with esthetic results.