good bars are passive and do not cause stresses. BAD bars, well that's another matter.
very true. now can you say with any degree of certainty that the bars coming from a plaster model at +/- 100um, milled in a machine capable of +/- 10um give passive fit? that Nobel course as listed above will tell you passive fit is +/- 2microns.
are we at all certain a 3dprinted structure would be better? i highly doubt it. 3dprinted metals have memory. more so than cast, and milled.
can you say with any certainty that the plethora of labs that would make bars on their 40k machine can do as good as a cnc worth a quarter million, backed by professional cnc machinists?
the solution that labs are adopting is ridiculous and terrible. but its cheap, and its sexy and makes you feel good so it sells.
#2, no you might not put denture teeth on bars but tons of labs will make zirconia super rigid brittle doodads with built in teeth. these things are so durable they will be digging up the bones of people who had them 3000 years from now and go hey look he had one of those zirconia prosthetics, then probably dust it off and teleport it to a museum.
what i'm saying is this rigid structure isn't the best for the patient, and reduces the lifespan of the implant. a SEMI-rigid material like trinia which can deform up to 1.5mm before breaking to undue stress, is far more valuable to labs looking for working solutions on the cheap acrylic can't do that zirconia cant do that. drop a zirconia frame one day see how well it absorbs impact. tell me how its good for anyone and their pocketbook?
the longevity of an all on x case depends entirely on passivity of fit, and if that cannot be guaranteed outside of a cnc worth a quarter million then the obvious solution is to go to a flexible alternative, or buy nobel's premanufactured all on 3 solution and don't think about it. but who wants to do that? nobody. which is great because trefoil isnt marketed to labs anyway, its marketed to surgeons and gp's. nobel wants to actively cut you out of making bars, and cut Panthera out too (if you didnt know they used to be Nobel). Nobel has an ACTIVE interest in sh!tting all over you as a lab because with the more tool you as a lab have for making quality work, the less money nobel makes. I wouldn't go to a nobel course except for a free lunch, and I'd probably complain even about that.