It's covered by most employer health plans, so patients don't see the true cost and don't shop around much. That's not the case for lasik or elective plastic surgery.
Of course since the latter are elective, customers have the luxury of shopping around and taking their time.
I'm not sure where you've been employed, but dental plans have always been separate from the actual health plans and generally cover nothing beyond giving a pittance per year that hardly rolls over. Once that's gone, you get to pay the full cost.
I've had to deal with the true cost of dental work and I can guarantee you anyone that's needed to deal with significant dental issues has had the same experience. So why hasn't the free market dropped down prices? Why are we still paying more for basic dental work compared to other countries?
Why haven't dental costs fallen through the floor if it's a free market?