I have Waggel insurance for my 2 younger dogs and they supposedly cover dental, the teeth must be checked yearly though, my older dog is uninsured, we save monthly for her and the cat, she has just recently had a dental and two extractions and 6 moles removed and was just over £500 at the new independent vets that has recently opened and is so much cheaper than corporate vets where she had a dental two years ago and one tooth and one mole removed and was nearly £900.

 

Sometimes going with cheaper insurance at the beginning is a false economy as the premiums tend to jump hugely.
I never had massive increases year to year with petplan, although have only had one pet insured if I used insurance again it’d be with them.

 

3rd option in between insurers who cover dental as standard, and those who don't cover it at all - those who have it as an optional add-on to your standard policy. One of mine is with Petgevity (previously called Petsure) who are one of the ones who do that. However I agree with @Arny that Petplan may be cheaper longer term, assuming there's no other reason why it's not a good fit.