It isn't as simple as just getting a vet to do a dental check. You need to be sure that the vet knows what guinea pig teeth should look like. I've had a few piggies arrive here at TEAS, after owners have been told that their guinea pigs teeth are so bad, that they need to be euthanised. After a dental check, by Simon Maddock, it has been found that either the problem is minor or in more than one case, there is no dental issue.
However, there has been numerous cases of piggies being deemed to not have a dental issue, and then being found to have a mouth full of ulceration, due to teeth growing into the cheeks.
Sadly so few vets can diagnose or deal with dental problems. Sorry to sound so negative, but after spending 7 years running TEAS, I have seen so many misdiagnosis or very poor treatment.