Micro-pulse TIG welding
in orthodontics and dental technology
In contrast to soldering with an open flame or resistance soldering (both with dental solder), where a small gap between the components is not a problem or is even useful, the aim with welding is generally to prepare the components to be joined without a gap, regardless of the welding technique used – whether with a Lampert PUK D6 micro-pulse welding unit or with a laser.
If the gap dimensions of the components to be welded are too large, welding will quickly become difficult. It can therefore be helpful to build up components such as the separating gap of a separate bridge with welding wire until at least one contact point is available again. The same applies to the construction of combined implant bars or individual (implant) crowns to be splinted.
To eliminate gaps due to poor fit, orthodontic components such as the base of a Herbst hinge or brackets can be ground to match the shape of the respective substructure or round wires can be ground flat in advance for welding.
This issue should generally also be kept in mind when bending wires, especially for orthodontic appliances where very thin materials such as bands with a material thickness of well under 0.2 mm need to be stably connected to thicker wires of over 1 mm.
Otherwise, no connection can be achieved, or it is very difficult and time-consuming to achieve by adding welding wire.
In certain cases, it makes sense to strategically attach stabilizing elements before welding a joint, e.g. in the case of a separated bridge or a model casting repair. This can be a casting channel, an old bridge, test objects or even a stored faulty casting, if possible made from the same alloy as the workpiece to be welded. Once the joint or build-up welding has been completed, these structures are cut off again and trimmed during the rest of the finishing process.
Because: Welding on dentures or delicate orthodontic constructions generally carries the risk of distortion, e.g. on a delicate sublingual bracket, and the energy used should always be applied in moderation!
The preparation for a welded joint therefore requires significantly greater precision than for a classic soldered joint. On the other hand, there is no need to produce a solder model and, if necessary, remove and reattach plastic parts.
As with all other dental applications , welding should only be started on clean, grease-free surfaces. Acetone or commercially available brake cleaner are very suitable for preparatory cleaning.
Prior sandblasting of highly polished surfaces, as is usual in certain cases with laser welding, is not necessary for TIG welding with Lampert devices. The surface finish of the workpieces has no influence on the quality and the welding process.
The condition of the tungsten electrode tip is even more important for orthodontic applications than for welding in traditional dental technology, and it may need to be changed more often than for other applications (as it is ground at both ends, it can be easily turned in the handpiece).
It is always advisable to start a new job or a new work section with a freshly sharpened electrode tip, especially in angular welding situations, in order to be able to reach the desired position precisely – the electrode always welds at the points where it touches the workpieces directly.
The welded joints should always be made as smooth as possible afterwards, but only as strong as absolutely necessary in order to avoid unnecessary weakening of the weld seam.
In conclusion, the greatest advantage of welding in dental technology and orthodontics over soldering is that stable welded joints can be produced without the use of solder.
This means greater safety for patients thanks to more stable connections with maximum biocompatibility.
Note: The examples shown only illustrate the various appliances in terms of their technical welding implementation and do not make any further technical claims with regard to medical aspects.
Individual, technical treatment considerations are of course reserved for medical specialists.
