OSCE

irreversible hydrocolloid

• Alginate

• Used for:

  • Bleach trays

  • Models

  • Pre-op impression ONLY

• Adv: cheap, easy to work w/

• Disadv: loss of accuracy, tissue distortion (synethis, inhibition)

reversible hydrocolloid

• Agar-agar

• Able to go from sol to gel, back to sol

• Used for:

  • Could be: Premil

  • Final imp

• Oldest

• Adv: accuracy

• Disadv: takes a lot of equipment

elastomeric

• Polysulfide

• Used for:

  • Could be: Premil

  • Final imp

• Rubberlike quality, base/catalyst, light & heavy body

• Adv: very stable & accurate

• Disadv: taste, stain, odor

silicone

• Polysiloxane & polyvinal siloxanes

• Used for:

  • Could be: Premil

  • Final imp

• Latex gloves affect set time

• Adv: highly accurate stable, base-catalyst

• Disadv: expensive

polyether

• Used for:

  • Could be: prelim imp

  • Final imp

• accurate, no distortion, quick set time

• adv: highly, accurate, stable

• disadv: expensive

stock tray

• full arch

• quadrant

• anterior

• disposable

• pre-manufactured

triple tray

• take impression of opposing teeth, bite registration & arch of interest

• triple tray as final: only as preliminary needed

custom tray

• made of acrylic or thermoplastic material for most accuracy

• beneficial for taking final imp

tofflemire

• universal retainer

• mechanical device that holds the matrix band

• used anywhere posterior

• utilizes retainer and band system

parts of a tofflemire

outer knob: secures matrix band

inner knob: extends/tightens the band

guide channels: holds matrix band

placement of tofflemire

• diagonal slot ALWAYS positioned toward gingiva

• retainer positioned at buccal/facial of tooth

• guide channel ALWAYS faces gingiva

• handle extends out

• matrix band: small circumference edge faces toward gingiva

matrix band

• thin, flexible stainless steel

• universal band: selected for class II

• Extension band: deeper class II prep requiring gingival extension

ironing band

if matrix band becomes creased or bent, smoothing it out with back end of mirror or acorn banisher

wedge

• holds band securly in place

• adapt band to gingival contour

• used to prevent overhangs

wooden vs plastic wedges

wooden: amalgams

plastic: composite or amalgam

selectional matrix system

• class II composite restorations to restore anatomical contacts

• produce tight anatomical contact

steps selectional matrix

1) matrix band placed interproximal

2) wedge is placed to close the cervical margin

3) prongs of tension ring placed between band and wedge

• create solid closure of cavity preparation