The Omori Group is a booming dentistry franchise company that doubled its sales to 1.07 billion yen last year and now aims to double them again to 2 billion yen this year.

But to share in this success, would-be Omori dentists have to do more than just wield a deft drill or fit a snug set of dentures.

These days, whatever Omori's mega-earnings might suggest, tending to the nation's teeth is a cut-throat business characterized by two competing trends -- on one hand, an over-supply of practitioners; on the other, millions of mouths that are healthier than they've ever been.