Matrix Systems Flashcards
what is a matrix system
any system designed to hug around a tooth during a restorative procedure to control the restorative material
purpose
to confine filling material to preparation
allow optimum condensation for amalgam restorations
allow reestablishment of proximal contact
restore physiologic contours to restoration
provide acceptable surface texture in areas that cannot be finished or burnished
tofflemire
most commonly used for both posterior amalgam and composite
tofflemire matrix bands
flat bands made of dead soft material with no memory
various thickness and shapes
when formed into a loop creates a rough anatomic form of a tooth
band contouring
bands are flat and need to be contoured
use a burnisher
assembly
must be done in such a way as to be able to remove the retainer first
set screw knob should be directed towards front of mouth
when band is placed in retainer, one side of the loop has a greater diameter than the other; smallest diameter toward the gingiva
placement
should slide through contact; slight wedging with an instrument
band must extend all the way to gingival margin
tightened until a snug fit has been achieved
wedging
small triangular pieces of wood or plastic
various sizes
shaped to provide more physiologic contour of matrix
ensures adaptation of band to tooth
causes a slight spreading of tooth which helps in restoring contact area
wedge placement
buccal or lingual side
largest wedge that can fit
tightly placed
contouring
burnish and contour to impart the desired proximal shape and contact
burnish or any other instrument
pressure
tofflemire removal
remove wedge
loosen slide and then set screw
finger is placed on loop, retainer is removed from mouth
then remove band with cotton pliers, hemostat or fingers
band removal
tip band away from restoration when removing so that it does not damage the newly carved ridge
movement of band should be primarily buccal to lingual as band slips out of contact
band may be cut close to the tooth on lingual and pulled through the buccal
