Custom Trays Individualized trays for making final impressions Made on a diagnostic cast

Purpose of a Custom Tray Improve retention (border molded) Minimize: Impression material distortion Uniform thickness Rigid tray

Purpose of a Custom Tray Minimize: Tissue distortion Less viscous material Accurately adapted tray Costs less impression material used

Custom Material Light-cure resins (Triad) Auto polymerizing acrylic resin (e.g. SR-Ivolin) Fume hood Vacuum-form poly vinyl Thermoplastic materials

Monomer Hygiene Autopolymerizing resins have a liquid monomer that should be used in a fume hood Light cure materials for students

Extension 3-4 mm short of the peripheral role Diagnostic casts usually overextended (irreversible hydrocolloid)

Extension Outline the depth of vestibule vertical portion turns toward horizontal Through hamular notches across vibrating line Provide room for frenal attachments

Block-Out Undercuts Baseplate wax Prevent tray from locking onto cast Lubricate cast (Petroleum jelly or Alcote)

Wax Spacer One thickness of base plate wax over the cast Trim line in vestibule Trim to“butterfly” configuration glandular tissue

Wax Spacer Minimizes hydraulic pressures Do not place relief over blockout Already space from tissue Provides room for impression material

Triad Resin Light-cure Heat will melt wax spacer Cure under water Cures on exposure to ambient light

Triad Resin Exposed surface has air inhibited layer Air Barrier Coating Cytotoxic Must be thoroughly removed Cure under water

Triad Resin Wear gloves to minimize exposure to material Hypersensitivity potential minimal

Tru-Tray Material Remove from wrapper Adapt the resin over the spacer Palatal area adapted first

Large Casts Use portion of another sheet Adapt well until seam is gone Reclose material in wrapper, tape shut Infection control

Tru-Tray Material Trim excess with a scalpel, then readapt Cut down through resin Pulling blade will tear resin

Trimming the Tray

Handle Addition Small vertical handle Add before curing Does not pull vestibule Add before curing

Auxiliary Handles Mandible For stabilization Orientation the tongue Area of 2nd premolars / 1st molars

Curing in Water Prevents wax meltdown Water hazard Ensure: Top of container well sealed Outer container surface dry

Cure Time 4 minutes Cooling effect of water may extend cure time

Finish Arbor-bands and acrylic burs Round and smooth edges Mask and eye protection

Finish Do not polish - adhesion No holes until border molded

Tray for Border Molding with Partner More difficult than edentulous border molding Removal from teeth & undercuts Easier to lock in place Hybrid design

Tray Design