Impression For Fpd 3415u

à

c

c c c

cc

c

@

‡ ‡ ‡

Exact duplication of the prepared tooth including finish lines Other teeth and adjacent structures reproduced accurately Free of bubbles or voids especially in finish lines



Hydrophilic- Hydrocolloids, polyether[easy] Hydrophobic- polysulfide,polyvinyl siloxanes, condensation silicones

Viscosity Light body polysulfide & Con Silicone- Low viscous Heavy body polysulfide- High viscous[putty] 3 Cost

÷ Custom trays are most commonly made from acrylic resin tray material These materials should not be directly applied to the casts since impression material used in the tray requires room to flow Trays made for alginate require more relief {0 cm} than for elastomeric impression materials, which require less relief {0 3cm}

£] - The custom tray should be rigid throughout the impression procedures ] - The custom tray should retain its shape since low fusing materials and other impression materials has to be applied over it 3] - The tray should be simple so that it can be easily made and should be should cost less

X] - The tray should be able to trim since the extensions of the tray have to be adjusted ] - The borders of the tray should be smooth since sharp borders will injure the soft tissue £] cold cure or Self-cure acrylic ] Heat cure acrylic 3] Thermo set vinyl {vacuum adapted}

m Ê] Dough method ] Sprinkle on method £] Outline the extent of the tray on the cast by a lead pencil ] Êdapt relief wax above the cast and paint it with tinfoil substitute 3] Tray material is assembled with spatula, tray formers, measuring devices and separating medium

X] Tray formers are made by using base plate and forming a stone investment around them So two molds can be prepared for maxillary and mandibular tray ] Measure and mix the powder and liquid, which should be, thin and pour it into the mould which is already lubricated with petroleum jelly ] Êfter mold is filled with resin allow it to set until it becomes plastic ] Êfter setting remove it and adapt on the cast using the fingers and hold it ] Excess material is used to make a handle in front of the tray

â] Trim the borders of the tray and check it by placing on the cast and finally polish it with pumice £0] Perforations are made on the tray for adherence of impression material with the tray This is the conventional method by adding liquid to the powder directly on the cast ‡ Rigid & made hrs in advance ‡3 occlusal stops(3mm/3mm holes)made ‡Wax spacer (mm) & aluminium foil adapted ‡Handles and wings are made

- m ÷ m m

÷ àmà÷à ! " à÷à" à !÷!à#$ ÷!÷$ " (Ê) Putty reline technique () Double,single mix technique (C) machine mix technique [Pentamix} à" à !m %÷ & $' ÷" (÷ '!

÷ !-!à ! ÷!à#$ $ à!÷!à#$à ‡ ) * + ‡ , ‡à ‡ ‡ , ‡m

£





o





mà! à" à !

$ à!÷!à#$àà ÕÊdhesive (polysiloxane with ethyl silicate) is coated ÕPolyvinyl siloxane loaded in the stock tray Õcellophane strip adapted on prepared teeth ÕThe impression is obtained and the strip is removed ÕLight body impression material is applied and final impression

done Õmpression is held for min

£





£



£





' $' "à-÷!à#$ Õ

Custom tray coated with adhesive

Õ

Light body material is loaded in syringe

Õ

Medium / heavy body material is loaded in custom tray

Õ

Retraction cords removed and syringe material expressed on prepared teeth

Õ

Custom tray with medium / heavy body seated in patient¶s mouth

Õ

mpression held for minutes

à!m$ " $ 'à àà !) ÷÷ $ -à+

÷à !÷ ÷

à" à ! m"-à )m$

÷

" $ 'à àà !+

à!. "à-÷!à#$ inches of polyether base and acclerator paste is expressed The mix is spatulated for £ min Tray is loaded and syringe material is kept ready Retraction cords are removed Syringe material applied on prepared teeth Tray is seated in the mouth for X min

÷"÷à!"à-/!"à-

à" à !m %÷ à!à ÷÷!à#$ Õ Root canal is widened and impression is made by Orthodontic wire coated with elastomeric impression material Or urn out plastic can be used for impression of post Õ Light body impression material injected around the burn out plastic post Õ mpression made with medium body elastomeric impression material or putty

a

a

a

à!à!

÷!

à.' à" à !" à $!

à!.

à" à ! mà! ÷!

& $ ÷"

‡

0 1

‡

÷

‡



‡



‡

à

‡

-

! $