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Pinless duplication


The Monotrac V2 Anterior pinless system simplifies model and die duplication.

By James Garland, CDT, BA. Information provided by Monotrac.


The Monotrac V2 Anterior pinless model and die system offers a simple, efficient solution for creating a refractory model. The master model and refractory model are one and the same, sharing the same articulated model with interchangeable master dies and refractory dies.

The pinless master model is prepared and dies trimmed, spacer is applied where needed, then dies duplicated with gun-injected polyvinyl impression material. The duplication is indexed to the master model to ensure perfect realignment. Then refractory dies are poured and replicated onto the same master model making the dies interchangeable. A bonus to the method is that if a refractory die is ruined and has to be repoured and replaced, there is no need to start from scratch. The adjacent master dies are placed back into the duplication leaving out the one that needs replacement. It is then repoured and positioned back onto the V2 base, providing the new replacement die.

Following are directions for creating anterior refractory dies using the V2 Anterior system.

THE TECHNIQUE IN PICTURES: SLIDESHOW
(refer to slideshow for figures)

01 Set up the master model on the V2 Anterior single-pour cast-in-place articulator (Fig. A). Note: The system saves significant time by eliminating grinding, pinning, gluing, basing, and mounting procedures.

02 Process and section the model, then prepare and trim the dies. Use a bur to place vertical indexing grooves on both the facial and lingual surfaces of the adjacent dies (Fig. B). Note: Leave a slight undercut in these grooves, which will retain and index the duplication to the model.

03 Inject VPS impression material over dies and into retention grooves to duplicate master dies (Fig. C). Note: Do not lift the tip of the gun while injecting to prevent suck back voids.

04 When duplicating longer spans, place an old bent bur into the material to make the duplication more rigid (Fig. D), then place extra material to bury the bur (Fig. E).

05 Remove the duplication and dies. Cut a funnel access window in the lower area of the duplication to allow the refractory to be poured into the duplication.

06 Spray the duplication with a surfactant and lightly blow dry. Paint a film of Vaseline onto all other surfaces that will come in contact with the refractory. Coat the base cones and adjacent die surfaces to prevent bonding.

07 Position the adjacent die sections into the index retention grooves of the duplication making sure they are fully and securely seated. Note the adjacent dies are two teeth wide (Fig. F).

08 Mix and vibrate the refractory into the die prep areas to just above the margin. Use a point to submerge into the prep areas to dislodge any bubbles (Fig. G).

09 Invert the V2 base over the adjacent dies and duplication, seating them fully into position while keeping inverted. Finish the pour filling to the top of the funnel opening using light vibration and tipping toward the lingual (Fig. H). Note: Avoid excessive vibration that can cause the refractory to bleed by or flash and distort the pour.

10 Remove the duplication (Fig. I). Remove the refractory from the base and section. The funnel shape can also be ground off.

Figure J shows the finished model with both master and refractory dies. If a replacement die is ever needed it is a simple process to recreate. 

V2 Anterior
	Features Pinless system for creating double bite impression cast-in-place setups Eliminates gluing, pinning, grinding, basing, and mounting procedures Tear-away base formers eliminate the need for rubber base molds Articulator base shape snap-fits into universal flex arm hinge, which allows natural 360° excursive movement in the occlusal plane
Monotrac Articulation www.monotrac.com 6936 So. Promenade Drive Salt Lake City, UT 84121 888-942-9494