For you, Nicole, since you’re in a city with an actual dental school: start there. They will likely be the most up front with pricing for services provided by folks with different levels of training, and that pricing with respect to ACA exchange dental plans.

For folks without access to such — if the plan covers certain evidenced-based care contingencies, and you fall into one of those categories or think you might, then yeah, get the insurance. I have terrible terrible teeth (chronic periodontis), and the cost of premiums + coinsurance at my dentist of choice is far less than cleanings (root scaling, oh boy) and imaging would be otherwise. I don’t even see a dentist in their super-preferred tier. (There’s a whole ‘nother parenthetical aside about what happens when you combine “terrible teeth” with “extreme phobia” and how when you do find a practice… THAT’S YOUR PRACTICE.)

Here’s an example of such contingencies:
https://www.uaex.edu/extension-policies/employee-benefits/fringe/dental-pdfs/Evidence_Based_Dentistry.pdf (I’m not an employee of the University of Arkansas or its Extension office. It’s just a handy PDF that covers much of what I’ve seen before.)

Dental insurance covers very little (in terms of $ or therapy) of the amount of health care you might need for your mouth. On the other hand, if you need it, it can be far, far better than nothing.

And have you read the June Thomas Slate.com series on The American Way of Dentistry? Watched some of the Frontline stuff on dental billing in the US?