L8. Matrix + Posterior Amalgam Restoration

"What is the purpose of a matrix system?

To provide a temporary wall for proper contour and contact during restoration"

"What is the most commonly used matrix system for amalgam?

Tofflemire matrix system"

"When is a Tofflemire matrix always used?

With amalgam restorations"

"Can a Tofflemire be used with composite?

Yes but it is optional"

"What happens if the Tofflemire band is too tight?

It may tear"

"What determines matrix band selection?

Tooth size and location of restoration"

"What are types of matrix bands?

Straight and precontoured"

"What is a disadvantage of straight matrix bands?

Poor adaptation to tooth contour"

"What is a disadvantage of precontoured bands?

Difficult placement if contact not broken"

"What direction should the open end of the retainer face?

Gingival direction"

"Which part of the Tofflemire tightens the band?

Large tightening knob"

"What is the purpose of the small knob on Tofflemire?

Adjusts loop size"

"Which side of matrix band faces gingival?

Smaller circumference"

"What is the purpose of wedging?

To separate teeth and adapt matrix to gingival margin"

"Why is tooth separation needed?

To compensate for thickness of matrix band"

"What happens if no wedge is used?

Open contact and overhangs"

"What type of wedge provides separation?

Wooden wedge"

"What type of wedge does NOT provide separation?

Plastic wedge"

"What is burnishing of matrix band?

Pressing band against adjacent tooth to improve contact"

"Why is burnishing important?

Helps create proper proximal contact"

"What is a common mistake with matrix placement?

Poor adaptation leading to overhang"

"What is an overhang?

Excess restorative material extending beyond margin"

"Why are overhangs problematic?

They trap plaque and cause periodontal issues"

"What is the biggest challenge in Class II restorations?

Achieving tight proximal contact"

"What happens if contact is too tight?

Difficulty flossing and discomfort"

"What happens if contact is open?

Food impaction"

"What is proper matrix band adaptation?

Close fit at gingival margin with no gaps"

"Why should matrix band be thin?

Improves adaptation and contact formation"

"What is the role of isolation in matrix placement?

Prevents contamination"

"What is the clinical goal of matrix systems?

Restore proper contour contact and marginal integrity"