Restorative - Final Exam Study Questions

Question 1

What class of cavities is a matrix used for?

Answer 1

Class II, III, and IV

Question 2

What is the shape and material of a maxtrix determined by?

Answer 2

The shape of a matrix system and or the material used is determined by its location and for what type of cavity prepartion.

Question 3

What are circumferential matrices usually used for?

Answer 3

Matrices that are circumferential are usually used to replace proximal, facial, or lingual walls.

Question 4

What are sectional matrices usually used for?

Answer 4

Sectional matrices are used for missing proximal walls.

Question 5

What are cervical matrices used for?

Answer 5

Cervical matrices are used for Class IV restorations.

Question 6

Benefit of Clear Plastic Matrix system?

Answer 6

A matrix system made of clear plastic will allow the operator to utilize the curing light more effectively when placing a light cured restorative material. They are often used for anterior restorations of Class IV buccal restorations.

Question 7

What are Wedges?

Answer 7

Wedges may be used in conjunction with a matrix system to achieve proper interproximal contacts. They are placed next to the matrix band using wedge placement forceps or cotton forceps, into the embrasure space for each missing proximal wall.

Question 8

The function of wedges is to:

Answer 8

Hold the matrix band firmly against the gingival margin of the preparation
-To prevent overhangs on restorations.
- Provide slight separation between the teeth, ensuring an accurate contact space and compensating for the thickness of the matrix band, creating a tight contact between the finished restoration and the adjacent tooth

Question 9

The most commonly used shape of wedge is?

Answer 9

The most commonly used type of wedge is triangular.

Question 10

What to consider when using a wedge?

Answer 10

1. The wedge must be wide enough so that pressure is applied to the apical and gingival walls of the preparation.
2. The wedge presses the band against the tooth and causes a slight separation of the teeth.

3.The wedge is slightly wider than the distance between the cervical portions of adjacent teeth.

Question 11

What class of cavities is Celluloid strip matrix system used for?

Answer 11

Class III or IV when the proximal wall of an anterior tooth is missing

Question 12

The plastic matrix (also called celluloid strip or mylar strip) and wedge serve the following purposes during the restoration process:

Answer 12

-The matrix is placed interproximal before the etching and bonding of the tooth to protect adjacent teeth from these materials.
-After the placement of composite material, the matrix is pulled tightly around the tooth to help in reconstructing its natural contour.
-The clear plastic matrix allows the curing light to penetrate the material, thereby completing the curing process.

Question 13

What is the T-band matrix system?

Answer 13

The T-band is a band in the shape of a T that can be easily placed, contoured and removed. When formed, the top portion of the T allows the straight portion to adjust and fit the circumference of a primary molar.

Question 14

Properties of a T-Band Matrix

Answer 14

-The T-band is available in two types, narrow width, and wide width, with a choice of stainless steel or brass material.
-The material is sturdy but can be adequately contoured.
-The loop may be prepared in advance and slipped over the tooth and tightened before the preparation is made to save time.

Question 15

What is a sectional matrix system?

Answer 15

The sectional matrix system facilitates the implementation of tight, anatomically correct contacts for Class II and MOD posterior composite restorations. The sectional system uses small contoured sections, rather than long cicrumferential bands, which are placed interproximally and secured by tension rings.

Question 16

Components of a Sectional Matrix System

Answer 16

1.Different sizes of contoured sectional matrix beans.
2.Two tension rings with differing tine lengths (long and short). The ring is applied to the tooth after the matrix bean is in place.
3. Tension ring forceps used to open the ring.

Question 17

How to use a sectional matrix system

Answer 17

One sectional matrix bean is applied for each interproximal surface being restored. The system allows for the overlapping of tension rings when doing a MOD or for multiple restorations in one quadrant. Using the tension ring forceps, the tension rings are applied to the tooth after the sectional matrix bean and wedge is in place. The tension ring is placed with the tines between the sectional matrix bean and the wedge.

Question 18

What is a Tofflemire Retainer?

Answer 18

The Tofflemire matrix system is a metal device consisting of a retainer and a band used for posterior restorations. It is one of the oldest systems and most commonly used.

Question 19

The 3 types of retainers:

Answer 19

1. Universal (buccal)
2. Contra-angle (lingual)
3. Pediatric

Question 20

Description of Universal (buccal) retainer?

Answer 20

The buccal retainer has guide channels that are flat or even with the diagonal slot vise. This retainer sits flat against the teeth in the mucco-buccal fold and the retainer is always placed on the buccal surface of the tooth.

Question 21

Description of Contra-angle (lingual) retainer?

Answer 21

The lingual retainer has the guide channels set at an angle to the diagonal slot vise and this retainer is always placed on the lingual surface of the teeth. When the retainer is in place, it lies at an angle to the teeth so the metal does not damage the enamel surface of the remaining teeth in the arch.

Question 22

Description of Pediatric retainer?

Answer 22

The pediatric tofflemire retainer is smaller in all dimensions than the Universal or Lingual retainers to accommodate the smaller mouth of a child.

Question 23

Retainer Components

Answer 23

1. Guide Channels
2. Diagonal Slot Vise
3. The Spindle
4. Inner Nut
5. The Outer Nut

Question 24

What is the purpose of guide channels on retainer?

Answer 24

Enable the loop of the matrix band to be guided in one of three directions. The direction selected is determined by the quadrant involved.

Question 25

What is the purpose of a Diagonal Slot Vise on retainer?

Answer 25

Is used to position the ends of the matrix band within the retainer.

Question 26

What is the Spindle purpose on retainer?

Answer 26

Is a screw that is used to hold the ends of the matrix band securely in the diagonal slot vise.

Question 27

What is the purpose of the Inner Nut on retainer?

Answer 27

Is used to adjust the size of the matrix band around the tooth

Question 28

What is the purpose of the Outer Nut on a retainer?

Answer 28

Is used to tighten the spindle and position it within the diagonal slot vise.

Question 29

How to assmble a retainer?

Answer 29

1. Look carefully at your retainer and note the side with the diagonal slot where the ends of the band are placed into.
2. This side of the retainer is always placed toward the gingival margin of the tooth.
   3.This may be easier to remember when you realize that after the operator has placed the restoration, they will remove the matrix retainer first, temporarily leaving the band in position.
   4.The only way this can be done is if the diagonal slot is toward the gingiva and the retainer can be lifted away from the band.
3. Look at the spindle in your retainer.
4. Before beginning to assemble the retainer and band, the spindle point must be clear of the diagonal slot.
5. Turn the spindle away from the diagonal slot.
6. To adjust the spindle, turn the outer nut counter-clockwise until the spindle is no longer visible in the diagonal slot.

CAUTION – if you turn the spindle too far counter-clockwise, the diagonal slot vise will fall off the spindle. If this happens, insert the end of the spindle into the diagonal slot vise and turn the outer nut clockwise.