Yes, PLEASE have the vet do a dental exam! If he's reluctant, find another vet to do it. At least he should do a visual check with a scope, but I would prefer dental xrays be done also in case it's his tooth roots that are bothering him. Loki's molar spurs were very slight and it wasn't thought to be the initial problem until they saw his molar roots on the xrays. They were too long and causing a lot of soreness.