Another vote for "not worth it." Too many restrictions. Many/most of the less expensive plans require patients to use certain dentists. When I researched a few, the only participating offices were those chain places.
I've never had any of these things happen before but had a run of bad luck last year and broke a tooth, two crowns cracked, and I needed three root canals. It cost upwards of $8K, but dental insurance wouldn't have covered most of it anyway.
Here's an example of plans through
AARP.