Dental problems

I'm so worried about Stomps. I took him to the vet last weekend because he's not been eating very much. The vet said he had bad gingivitis and needed a dental. I reminded her that he had a dental cleaning at that very clinic not six months ago. His gums are very inflamed, so she prescribed an anti-inflammatory, took some blood and sent me on my way. Since then I've changed Stomps food to soft food and given him the anti-inflammatory and an antibiotic, but he still won't eat. He typically won't start eating his food until Lightning makes a play for it. We've been going through this for years. Since I switched Stomps to wet food, Lightning is desperate to get at it. I monitor things so that Stomps thinks an attempt has been made but Lightning can't actually get to it. But this morning Lightning got past me and didn't give up when Stomps growled, and Stomps wound up attacking Lightning. It was a horrible fight that went on for what seemed like forever. There was blood on both dogs but I couldn't find any actual wounds. Obviously from now on they will be kept apart during feedings. And I'm making an appointment with a dental specialist. I think his teeth need more than just cleaning. I'm sorry this message is so long and rambling, but I'm really worried about him. He's a rescue so I don't know his exact age, but he's at least 10 and probably more like 12. In the last few months he seems to have aged dramatically. Has anyone else had an older dog with teeth problems? Is there anything else I should be doing? Is there anything else I should ask the vet to check for?