Restorative - Week 10 PP

Question 1

Posterior Matrix Systems

Answer 1

-Universal retainer- also referred to as Tofflemire retainer
* A mechanical device that holds the matrix band snugly in position
* Positioned most commonly from the buccal surface of the tooth being restored

Question 2

Matrix Bands

Answer 2

Thin, flexible stainless steel material
The two designs most commonly used are:

• Universal band: Selected for the class II preparation
  when the proximal box is prepared to a minimum
  depth and width and the cusps are intact
• Extension band: Selected for the deeper class II
  preparation requiring gingival extensions

Question 3

Matrix Bands

Answer 3

The design of the matrix band is such that when the
ends of the band are brought together, the band will
form a circle
* One side of the circumference of the circle will be
smaller than the other side
The circumference guides you in placing the band:
* Smaller circumference: Gingival edge and is always
positioned toward the gingiva
* Larger circumference: Occlusal edge and is always
positioned facing toward the occlusal part of the tooth

Question 4

Contouring the Matrix Band

Answer 4

The center of the matrix band should be contoured
in the proximal contact area so the final restoration
will have proper contact with the adjacent tooth
* To contour the band, place on a paper pad. Using a
burnisher or end of the mirror handle, rub against the
inner surface of the band until the ends begin to curl

Question 5

Wedges

Answer 5

Class II restorations require a matrix band to act as an artificial wall for the tooth.
- The matrix band alone does not provide the
anatomic contour required interproximally
- A wedge is inserted into the lingual embrasure
to hold the matrix band firmly against the gingival
margin of the preparation