prosthodontics

The Wol-Ceram Electro-Layered Chip-Bridge-System

2007-10-15

The Wol-Ceram Electro-Layered Chip-Bridge-System

Die Preparation

The fabrication of the Wol-Ceram ELC chip-bridge system involves the preparation of the model. This preparation is similar to the copings die preparation, where the workable area of the prepared die should combine an specific height in order to avoid fracture of the dipped bridge, and the ditching of the die needs to be deeper than a typical PFM; this would facilitate removal of excess material around the finished electroplated bridge.

Mount the bridge into the bridge holder

Fix the bridge into position

Putty material is used to mount the bridge into the bridge holder. The distance from the bridge holder to the margin has to be 1 ¼ inches.

When fixing the bridge into position, make sure the die is not leaning to either side.

Bridge Preparation

After the master die has been prepared and placed correctly in the Wol-Ceram bridge holder, the bridge model is ready for the electro–layering preparation. Below are the steps for the actual preparation of the die before going to the electro–layering process.

Note: The steps below should be read from Left to Right.


	A very thin layer of pink spacer wax is brushed onto the die. Be sure not to brush towards the margin or material will accumulate resulting in a weak margin.			A layer of wax is applied to the coping sides and any undercuts are blocked out. The proper thickness is achieved when the die is no longer visible.

	Using the spacer brush, the wax is evened out to achieve a smooth layer. This is very important because the bridge’s inner surface will be an exact replica of the wax surface.			A thin coat of alumina powder is then applied the die. Be sure not to leave clumps of powder and to blow off any excess material. This facilitates application of the In-Ceram material during the dipping process.

	A nose is made from the putty and applied it to the buccal side of a posterior bridge or the lingual side of an anterior bridge.			The margin is marked with a red pencil.

	The ELC chips are available in different sizes. Measure your bridge span and match the size to the correct chip.			By bending the chip with tweasers, the tooth’s cusp can be duplicated. Also, adjust you chip to conform with the buccal shape of the dies.

	The chip is then dusted with alumina powder.			Place the prepared ELC chip onto the putty’s nose. Pressing down on the chip engages it into position.

	There should be a gap from .5 to .8 mm between the chip and the die. They should not be touching. The connector of the chip should be 1 mm below the top of the preparation.			Fold the chip at the base before snapping on the connection clip. Failing to do so may cause the bridge to fail.

Fabrication of the Wol-Ceram Electro-Layered Bridge

After the preparation of the bridge, the die is ready for the electro–layering process. By running the adequate software options from the machine (See the Wol-Ceram Instructions Manual “Running the Software”), the electro–layering process will start. Below are the steps for the actual electro–layering process.

Note: The steps below should be read from Left to Right.


	Place the die in a manner that when it is dipped into the in-ceram material the bridge will not make contact and damage the glass rod.			After the electro–layering process, the die will be dried and the machine will go to its default position, at this point the electro–layering process is finish.

	A Round Scaler tool is used to remove material off the interproximal margin. Also a Long Scaler could be used to remove the material from beneath the margin.			A margin polisher is used to prepare the outer margin.

	The ELC Chip is cut using a small disc. Also a fissure burr could be used to cut any remaining In-Ceram material that cannot be reached with the disc.			The coping is heated approximately 1 minute to melt the spacer wax and your bridge is ready to be pulled off.

	With light finger pressure, carefully remove the bridge from the die. The coping should be gripped on the sides of the insical/occlusal wall to reduce the chance of breakage when removing it from the die. If unable to easily remove the coping, check for possible engaged undercuts around the margin. Remove any excess material and warm the coping again. If the margin fractures during removal of the coping, it can be repaired.			After the bridge is pulled off, the next step is to sinter, and glass infiltrate the bridge.