WORKING CAST

is the cast that is mounted on an articulator. To provide the most accurate articulation, it normally should represent the entire arch

REQUIREMENTS FOR GOOD CASTSREQUIREMENTS FOR GOOD CASTS

1. bubble free1. bubble freeespecially along the finish lines of the especially along the finish lines of the

prepared teeth.prepared teeth. 2. distortion free.2. distortion free. 3. trimmed3. trimmed

to insure access for carving wax pattern to insure access for carving wax pattern margins.margins.

WORKING CAST WITH A SEPARATE DIE

WORKING CAST WITH A SEPARATE DIE

disadvantages wax pattern must be transferred from one to the

other internal adaptation

obtained from separate impressions pouring an elastomeric full-arch impression twice

first cast is used for fabrication of the die

IMPRESSION POURING

DIE PREPARATION

Stone is added Tray is tilted

DIE PREPARATION

Stone is added to the impression

The die is first trimmed on a model trimmer

DIE PREPARATION

handle is slightly larger than preparation. Improperly trimmed die

DIE PREPARATION

The handle should be 1 inch long

The die is trimmed with an acrylic bur.

DIE PREPARATION

Shaping near the finish line with a scalpel

The die is with the discoid end of a Tanner carver

ERROR !!!This die is too short, and it does not allow adequate access for margin finishing.

DIE CONTOURS SHOULD BE SIMILAR TO THOSE OF A NATURAL TOOTH

DIE PREPARATIONAxial contours of the wax pattern are influenced by die trimming.

finish line on die outlined with a redred pencil.

DIE PREPARATION

Die relief agent One-piece die

WORKING CAST WITH A REMOVABLE DIE

IF A REMOVABLE DIE SYSTEM IS USED, IT SHOULD SATISFY THESE REQUIREMENTS17

The dies must return to their exact original positions.

2. The dies must remain stable, even when inverted.

3. The cast containing the dies must be easy to mount on an articulator

WORKING CAST WITH A REMOVABLE DIE

Most of these devices can either be oriented in the impression before it is poured

attached to the underside of a cast that has already been poured

prepour technique post-pour technique

WORKING CAST WITH A REMOVABLE DIE

1. Straight dowel pin 2. Curved dowel pin 3. Pindex system 4. Di-Lok tray 5. Accutrac

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A, flat-sided single dowel;

B, single curved dowel;

C, double straight dowels with a common head;

D, two separate parallel dowels;

E, keyed plastic outer tray

STRAIGHT DOWEL PIN

Dowel pins positioned over the impression

Paper clips are added to nonremovable parts

The stone around the dowel pins is lubricated

paper towel used to fill in the open, center portion

Wax at the ends of the dowel pins is removed

Dies are separated from the rest of the cast

the ends of the dowel pins are tapped to loosen

Base of die is trimmed with an acrylic bur.

Dies are reseated into the cast

wax is removed from the ends of the dowel pins.

PART 2

ANY QUESTION ?

CURVED DOWEL PIN

curved dowel (A), positioning bar (B), straight pins (C)

first pour of die stone (D) to the impression

Depressions are made about 2.0 mm deep on either side of the dowels in the two large segments of the cast that will carry the unprepared teeth

CURVED DOWEL PIN

coat of petrolatum is applied to stone & dowels

Boxing wax with the tips of the dowels sticking

CURVED DOWEL PIN

CURVED DOWEL PIN

The completed cast is sawed

Segment is removed by pressing on the exposed tip

CEMENTED CURVED PIN

CEMENTED CURVED PIN

The working cast is trimmed to receive cemented dowels

Holes are drilled into the underside of the cast, under the indicated locations

CEMENTED CURVED PIN

The cast is keyed with a large acrylic bur cyanoacrylate cement

CEMENTED CURVED PIN

The head of a curved dowel is seated

saw cuts after the base is poured

PINDEX SYSTEM

PARTS OF THE PINDEX MACHINE.

PINDEX SYSTEM

sufficient stone to allow for trimming is added

The bottom of the cast is trimmed

PINDEX SYSTEM

The cast should be 15 mm thick

The periphery of the cast is trimmed

PINDEX SYSTEM

The palate/tongue area is trimmed

Location of the pin holes is marked with a pencil

PINDEX SYSTEM

Pencil marks are placed under illuminated dot

The thumbs are used to stabilize the cast while lifting the handle bar with the fingers.

PINDEX SYSTEM

Debris is removed Debris is removed pin holes refined pin holes refined

Shorter pins 1stShorter pins 1st Cyanoacrylate cementCyanoacrylate cement

PINDEX SYSTEM

White sleeves > long White sleeves > long pins pins

bottom of cast is bottom of cast is lubricated lubricated

Utility wax > long pins.Utility wax > long pins. gray sleeves are blocked gray sleeves are blocked

PINDEX SYSTEM

A palatal/tongue fillerA palatal/tongue filler The filler is placed on the The filler is placed on the castcast

Boxing waxBoxing wax The filler is seated to the The filler is seated to the castcast

PINDEX SYSTEM

Microstone is pouredMicrostone is poured The base former filledThe base former filled

Model seated to base Model seated to base former former

Stone is vibrated on Stone is vibrated on bottom bottom

PINDEX SYSTEM

Wax over the long pins is Wax over the long pins is removed.removed.

The saw The saw cuts are cuts are premarkedpremarked

Dies are sectioned from the Dies are sectioned from the undersideunderside

The cast is removed by The cast is removed by tapping the pinstapping the pins

PINDEX SYSTEM

Dies may also sectioned from the occlusal

A large condenser also be used to loosen

cast should be poured in a U shape, no stone in the center.

The completed cast on the articulator

PINDEX SYSTEM

The lingual side of the cast base is trimmed with an arbor band.

Horizontal grooves are cut in the base to give it retention

DI-LOK TRAY

DI-LOK TRAY

The cast is placed into stone in the tray

Disassembly of the cast.

A saw cut is made on each side of the prepared tooth

The cast is loosed by tapping on the front of the base

DI-LOK TRAY

The prepared tooth is broken free from the cast

die is trimmed

The cast and tray mounted on the articulator

The cast and die(s) are reassembled in the tray

مارژین که صورتی مارژین در که صورتی دربه خورده تراش به دندان خورده تراش دندانباشد نزدیک مجاور باشد دندان نزدیک مجاور دندانترجیح دای تکنیک ترجیح کدام دای تکنیک کدام

؟ ؟ دارد دارد