Here, dental insurance isn’t really “insurance” like health insurance. Everyone needs dental work and preventative. Dental insurance is better thought of as a “discount plan”.
The cost of preventative is factored in. You have to go to their dentists with whom they have a relationship with and have negotiated a rate. And then they barely pay anything on major stuff.
If an employer is paying for it, great, it’s a little bonus–but I don’t think it is usually in your best interest to sign up out of pocket, unless you know you need something major done and the premium is less than the maximum payout. BUT–usually these plans (when signed up individually) have a waiting period on major items. This means you have to factor in 2 years of premiums to see if it is worth it.
On a side note, if you do need some major work done, there are a lot of different countries you can go to and get it done for a lot less and also get a vacation in at the same time.