We have been laser sintering NP metal with Attenborough in the uk since around 2008. More recently with argen in the uk for precious metals and Heraeus kulzer in Germany for NP c&b and full arch implant substructures with great success! Heraeus seems to be the best of the lot, everything drops on without any issues! We tend to achieve a much better fit with SLM than milled frames. The frames also take up less occlusal space because there is no radius compensation!