Extension of a cast partial denture

The wire used here (2 mm, half-round, cobalt-based alloy) is first bent into the desired shape and ground to the bow with as few gaps as possible.

In this specific example, the retention is placed directly on a fairly stable sublingual bar and welded. A much nicer but also more time-consuming preparation would be to grind a bed for the wire, fit the wire flush into it and only then weld it to the bar (Fig. below).

It is always important to weigh up what task the repair to be carried out has to fulfill: perhaps just a quick emergency repair or a short stopgap until a new prosthesis can be produced. In many cases, the most elegant and stable solution will be a cast component, whereby the position, dimensions and shape of the connection should always be chosen with care.

If it is a very delicate construction, a fixation at a suitable point to avoid distortion could be considered, similar to the welding of a bridge, e.g. in the form of a sprue, attached transversely with only 4 – 6 welding points, which can be easily removed afterwards.

In the following application video, the welding geometry    was used for joints and angled situations. The welding parameters range between 35 – 50 % power and approx. 3 – 5 ms pulse duration. If the component is more delicate, it is advisable to select the parameters somewhat more defensively and to occasionally set strategic counter-welding points on the underside of the bracket.

After welding the joint, it is advisable to apply at least one more complete layer of suitable welding wire to reinforce the joint in order to create more scope for subsequent finishing and polishing. The welded joints should always be finished smoothly afterwards, but only as much as absolutely necessary to avoid unnecessary weakening of the weld seam.