I use James spy. He's super with my youngster, who had never had his teeth done before. He has a really nice, Quiet approach. Can't recommend him enough!
Please ensure any edt you use is fully qualified. If there were any future problems using an unqualified edt could invalidate an insurance claim. Also some courses abroad are very short and aren't recognised by veterinary bodies here.
I second James Spy. As eventingmum mentioned, the insurance point is a very important one - my old boy was referred to Paddy Dixon at The Bush for some more extensive work. Think my bill would have been close to £1k, but luckily Petplan covered it as I had a full dental history (charts etc.) because I had been using JS and he'd requested the referral. They wouldn't have accepted the claim if I'd had no records.
I'm reluctant to recommend anyone for anything having been stung before but more than happy to recommend James.
Prior to him I used the equine vet practice I was with. They sedated and it transpired didn't do a very good/thorough job. James has transformed my horse and he now stands like a rock to get done. He previously reacted out of genuine fear but James was/is incredibly patient and has a way with horses.
I'm with a different vet practice now and haven't looked back. A couple of vet due-hardship have swapped to using James and a third is using him next time. The most recent horse on my yard couldn't be done without a lot of sedation and had extreme reactions to getting his teeth done. James got him done with no hassle and no sedation. I thought the owner was going to cry she was so happy and her horse was so relaxed throughout.
Ditto Eventing Mum; make sure whoever you use if fully trained, qualified, registered and insured.