Apollo Global Management Inc. has invested in Swiss dental firm vVardis Holding AG in a deal that values the company founded by two sisters at about about $1 billion, according to people familiar with the matter.

Co-chief executive officers Haley and Goly Abivardi, both of whom are dentists, will retain an approximately 70% stake in vVardis, said the people, who asked not to be identified because the financial details of the transaction are private. Representatives for Apollo and vVardis declined to comment on the financial details.