[Tear resistance of laser-welded dental alloys]

The investigation was undertaken to establish the place of lasers as tools in the dental technical laboratory. Tests were undertaken to study resistance to tears in laser welded dental metal alloys. (Degudent U, Degulor M of Fa. Degussa.) Availabel as laser apparatus were a cw Nd:YAG-laser (400 Watt capacity) and a pulse Nd:YAG-laser (max. 45 pulse energy, 9.2 pulse length). Welding tests on models with both lasers resulted in higher resistance to tears than was achievable by conventional soldering processes. Furthermore it could be shown that in certain alloy compositions, used in our experiments, welding by the cw process resulted in greater resistance to fissuring than by the pulse process. By adopting the alloy as well as the preparation of appliances to the laser process we feel that markedly superior results can be achieved as we describe in this first communication.