ch 49 Matrix systems

Which of the following restorations requires one wedge?

#15/MO (maxillary left second molar) amalgam #14/DO (maxillary left first molar) amalgam #1/MOD (maxillary right third molar) amalgam

Which of the following restorations requires two wedges?

#2/MOD (Maxillary right second molar) amalgam

How many wedges should be placed to restore a DO amalgam on tooth #17(mandibular left third molar)?

0

When placing a matrix for Dr. Jones' 9AM patient, you notice that none of the wedges in your kit are wide enough to seal the band to the gingival margin of the preparation and separate the teeth. What is the likely consequence of this situation?

Amalgam may flow past the margin during condensation A small gap may be left between the amalgam and the adjacent tooth Dr. Jones will need to use a carver to remove the excess amalgam past the gingival margin

Which of the following restorations is best performed with a T-band?

B/MO amalgam

When restoring a primary molar, what matrix system is recommended?

T-Band matrix

Posterior composite resin restorations do not lend themselves to a standard matrix and retainer. Which of the following statements is not true?

Tight contacts with the adjacent tooth are less important with composite resin restorations

Dr. Smith prepared tooth #30 for an MODB amalgam restoration which involves restoring the distobuccal cusp; he's directed you to place the Tofflemire matrix on the tooth. What modification to your usual technique might you employ in this situation?

Use a contra-angle Tofflemire retainer

Which of the following is used to restore anterior teeth with composite resin?

celluloid strip

What instrument is used to check that the gingival margin is sealed before mixing the amalgam?

explorer

What type of matrix band is used for preparations that extend toward the root of the posterior tooth?

extension

Failure to create a tight seal at the gingival margin using the wedge when restoring a proximal surface with amalgam will lead to which of the following?

overhang

Which step is performed first in removing a matrix band?

the retainer is removed

Careful use of the celluloid matrix provides a polished finish to the composite resin restoration

true

The diagram below demonstrates a poor placement of the wedge that will allow amalgam to escape forming an overhang

true

The matrix band is burnished to provide a more anatomic contour to the restoration.

true

What type of matrix band is used for preparations that do not extend toward the root of the posterior tooth?

universal

Which of the following is used to separate the teeth and compress the band against the tooth to avoid overhangs?

wedge