NASHVILLE, Tenn. (WSMV) - SmileDirectClub has officially shut down its global operations effective Friday. The at-home tooth-straightening start-up, headquartered in Nashville, shut down all operations leaving their workers without a job.

The telehealth company, which sold teeth alignment devices to two million customers, was unprofitable and had been criticized by medical groups.

The “Lifetime Smile Guarantee” has been eliminated “effective immediately,” while payment plan customers are expected to continue making payments and refund protocols are not yet clear.

The market leader provides a service you almost certainly use even if you don't know the bankrupt brand's name.