The best known divestiture was probably AT &T. The Government was the culprit causing the actions decades ago.
Back "then" companies were trying to be conglamorates; having many different businesses under one roof. Bigger was better. I am not going to study "timelines", but it was over a decade ago that many companies, on their own, started to divest themselves of unprofitable business or businesses that were not their core strength.
Most divestitures now are Company mandated. It is a way to focus on your strengths.
Obviously RRHI felt their focus should be mining. I am sure this has to do with capital needed to get Lantis going. Capital put toward mining appears to provide a better return then trying to use any to get the Dental Technology to market.
Although I really felt strongly about OCT, if just mining will bring a better return to stockholders, I can't fault the decision.
It will be interesting to see if Stan and Greg can do something with the software and patents they possess anytime in the near future.