Getting good data on the Tooth Fairy's generosity these days is like pulling teeth.

Two reports on the average amount left behind by the legendary visitor offer conflicting results -- and evidence that the Minnesota version is a cheapskate.

A recent Visa survey had the average gift per tooth falling 13 percent, from $3 last year to $2.60. In March, a Delta Dental of Minnesota poll had the average rising 18 percent, from $2.13 to $2.52.

But it's more than the numbers that are in dispute.

Delta Dental of Minnesota spokeswoman Heather Hofmeister said her company is "concerned that [Visa's] 'Tooth Fairy Survey' imitates our 'Tooth Fairy Poll.'" While the companies are not fighting tooth-and-nail, Hofmeister said, "We are reviewing this matter with legal counsel."

Delta Dental of Minnesota has conducted its poll annually since 1998. Visa's survey, taken in July, was its first.

There's also a cavity between the two reports on the Tooth Fairy's largesse in this neck of the woods. Visa's respondents had the Midwest tied with the West with an average reimbursement of $2.80, well ahead of the South's $2.60 and the East's $2.10. Delta Dental of Minnesota's poll had Minnesota children receiving an average of $2.01 per tooth.

"We've noticed over the years that giving typically varies by region," Hofmeister said, "but we don't know why."

Obviously, insight about incisors is hard to come by.