Custom TraysIndividualized trays for making final impressionsMade on a diagnostic cast

Purpose of a Custom TrayImprove retention (border molded)Minimize: Impression material distortion Uniform thicknessRigid tray

Purpose of a Custom TrayMinimize:Tissue distortion Less viscous materialAccurately adapted trayCosts less impression material used

Custom MaterialLight-cure resins (Triad)Auto polymerizing acrylic resin (e.g. SR-Ivolin)Fume hoodVacuum-form poly vinylThermoplastic materials

Monomer HygieneAutopolymerizing resins have a liquid monomer that should be used in a fume hoodLight cure materials for students

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

ExtensionOutline the depth of vestibulevertical portion turns toward horizontalThrough hamular notches across vibrating lineProvide room for frenal attachments

Block-Out UndercutsBaseplate waxPrevent tray from locking onto castLubricate cast (Petroleum jelly or Alcote)

Wax SpacerOne thickness of base plate wax over the castTrim line in vestibuleTrim tobutterfly configuration glandular tissue

Wax SpacerMinimizes hydraulic pressures Do not place relief over blockout Already space from tissueProvides room for impression material

Triad ResinLight-cureHeat will melt wax spacer Cure under waterCures on exposure to ambient light

Triad ResinExposed surface has air inhibited layerAir Barrier CoatingCytotoxicMust be thoroughly removedCure under water

Triad ResinWear gloves to minimize exposure to materialHypersensitivity potential minimal

Tru-Tray MaterialRemove from wrapperAdapt the resin over the spacerPalatal area adapted first

Large CastsUse portion of another sheetAdapt well until seam is goneReclose material in wrapper, tape shutInfection control

Tru-Tray MaterialTrim excess with a scalpel, then readapt Cut down through resinPulling blade will tear resin

Trimming the Tray

Handle AdditionSmall vertical handleDoes not pull vestibuleAdd before curing

Auxiliary HandlesMandibleFor stabilization Orientation the tongueArea of 2nd premolars / 1st molars

Curing in WaterPrevents wax meltdownWater hazard Ensure:Top of container well sealedOuter container surface dry

Cure Time 4 minutesCooling effect of water may extend cure time

FinishArbor-bands and acrylic burs Round and smooth edgesMask and eye protection

FinishDo not polish - adhesionNo holes until border molded

Tray for Border Moldingwith PartnerMore difficult than edentulous border moldingRemoval from teeth & undercutsEasier to lock in placeHybrid design

Tray Design