Ch. 49 test

Where should the cervical margin of a matrix band lie?

1mm beyond the gingival margin of the preparation

What is the correct order of steps for preparing the t band matrix

3,4,2,1

Once the AutoMatrix band is positioned on the tooth, how is the band tightened?

A wrench turns the coil clockwise to tighten the band.

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?

Between the band and wedge

A matrix must be used to create a temporary wall for which of the following classifications of tooth restoration?

Class II, III, IV

Which matrix system is used for anterior composite resin or glass ionomer restorations?

Clear plastic matrix

The tofflemire retainer that has been designed with a slight bend in the body to accomadate positioning from the lingual surface is known by what name ?

Contra angle

Why is a matrix band contoured prior to placing the restorative material?

Ensure that the final restoration will have proper contact with the adjacent tooth

Which of the following is the instrument of choice when positioning a wooden wedge?

Howe pliers

Mylar strips are used for class ___ restorations.

III

Where is the wedge positioned when placing a posterior restoration.

Lingual

Which of the following dental instruments is used to contour an anterior matrix band?

Mirror handle

If a patient is having a class ||| restoration on the maxillary central incisor, which type of matrix system would be used ?

Mylar system

What is one advantage of an automatrix over a universal matrix

No retainer to hold the band in place

The universal or tofflemire retainer holds the matrix band snugly in position. It is most often positioned in which area ?

On the buccal surface of the tooth being restored

What is the component of a universal matrix retainer that serves to hold the matrix band securely in the retainer?

Outer knob

What is the component of the universal matrix retainer that holds the matrix band securely in the device called ?

Outer knob

If a restoration is not contoured properly it can result in an

Overhang

Which matrix system is used with posterior composite restorations?

Palodent

What is the purpose of a matrix system ?

Provide a temporary interproximal wall for the restorative material and create an external surface against which the restorative material is packed

Which statement is correct concerning the purpose of the anterior matrix systems? (Select all that apply)

The matrix protects the adjacent teeth from the materials

Which statement is incorrect concerning placement of the matrix retainer and band ?

The seated band extends 2 to 3 mm above the occlusal surface of the tooth

Which statement is correct regarding posterior metal matrix Bands?

The smaller circumference is placed towards the gingiva

Which of the statements is incorrect about a spot-welded band?

The spot-welded band measures 3/4 to 1 in. Of copper material

What is the material of choice for a universal matrix band ?

Thin flexible stainless steel

Which matrix system used for class || posterior restorations is most common?

Tofflemire retainer and universal band

To contour a metal matrix band for posterior teeth, place the band on a paper pad and rub the inner surface of the band with _____ until the ends begin to curl.

a burnisher or the end of a mirror handle

Which statement is correct concerning wedges ?

a. A wedge is used to apply pressure to the apical and gingival walls of the preparation. & The wedge presses the band against the tooth, causing a slight separation of the teeth.

Why should stainless steel matrix bands not be used with composite resin materials?

a. Resins can be scratched by the stainless steel. b. Stainless steel can interfere with the setting of the resins.

What is the component of the universal matrix retainer that is always positioned in the mouth facing the gingiva called ?

diagonal slot

If a cusp is lost during preparation, which matrix band would provide the best support while restoring?

extension

The ____ is used to decrease the size of the matrix band loop after the band has been placed on the tooth

inner knob

The larger side of the universal matrix band loop is always directed toward which part of the tooth?

occlusal one third