September 30th, 2008 by admin

Numerous techniques are advocated for the fabrication of temporary recording bases
For temporary bases two most frequently used materials are shellac and cold curing acrylic resin
Autopolymerising resins are the most suitable materials for the fabrication of recording bases

Two basic techniques are used to fabricate recording base utilising cold-curing resins:

Non-flasking (Dough) method
Alternating applications of powder and liquid (Splitt-on) method

Dough Method

A thin layer of petrolatum (Vaseline) is applied to the prepared final cast.
All undercuts are blocked out with wax.
A tray resin is mixed according to manufacturer’s instructions.
When it has reached the doughy stage it is rolled to a cigar shape, placed on a roller board and roller to the desired thickness.
The resin sheet is transferred to the cast  and adapted
A sharp instrument is used to trim the excess resin
After polymerization has been completed; the resin base is removed and the borders are adjusted with burs.

The external surface is polished with wet pumice
The thickness on the facial slope of the ridge and over the crest of the ridge is reduced to 1 mm

Splint-on Method

With this technique well adapted bases can be formed
Undercuts are blocked out
Petrolatum is applied to the cast
A thin layer of powder is dusted over a small surface area of the cast sufficiently wetted with liquid to produce a slight flow
Alternate application of powder and liquid are made until a thickness of 2 to 3 mm has been developed
The completed base is then removed, trimmed and polished

The polimerizatiion reaction takes approximately 20 to 30 minutes

The base should not be removed during this period in order to prevent distortion