Can diclofenac help with dental pain?

I doubt it will help with tooth ache. I took it for years for degenerative spine disease. Worked well for that for a while.
But I can recommend Ibuprofen. It's one of the best pain meds out there outside of RX meds. I augment my hydrocodone with it so I don't have to take so much.

Diclofenac is an anti-inflammatory medication, most-likely used for orthopedic discomforts. So, while it may help with inflammatory pain, it would not likely help much with pain caused from an oral infection /periodontal disease. On it's own, it's anti-inflammatory action might help an infection to spread and it's hard on the stomach.
Acetaminophen (regular or arthritis strength) might be a better pain relief choice but, it also comes with warnings about possibly causing liver issues.