Can orajel for mouth sores work on toothaches also?

Sometimes:: It's a topical anesthetic, and so it will deaden pain if it's in contact with the exposed nerve.

Maybe - temporarily: You might get short term relief but it won't solve the underlying problem. Since it's a topical anesthetic, it may temporarily ease pain in the gum or a tooth that's open. But it won't help an infected tooth or deeper infection in the mouth. A toothache needs to be seen by the dentist for proper treatment.

Not effectively: Toothache caused by infection. Topical analgesic will not cure infection. Please, you need to see a Dentist ASAP.