I detect a bit of denial despite proof in the filings & directly from a company PR.
I can give you a method of how two companies can work together in R&D and keep R&D payments off the books. Use a third party. This way the other companies payments never hit Sintx coffers. We already have evidence of this via Sonnys research team which works outside of Sintx. Furthermore we have evidence that Zimmer likely paid said research team in 2017. You can deny these things all you want but the evidence is there. Some conclusive like todays PR, some not as conclusive yet very probable, like the 2017 milestone payment.
You mentioned how Sonny was quick to mention companies at Thalmann however those were companies they were working with well before that conference. Sintx was working with Dentsply & Morgan in 2016 yet this information was never disclosed when they actually raised funds mid 2016 and again Jan 2017. Nope it was revealed Sept 2017 only after I started connecting their JDA with Zimmer. Of course NGK is linked to Zimmer via JMDM.