His glucose is high because he either didn’t get insulin the day of his dental, he’s bouncing, or he’s not well regulated. It’s hard to say without a spreadsheet.
His BUN might be high because he could be dehydrated or perhaps he eats a high protein diet (like raw?). It would have been nice if they had done a urinalysis so we could see the urine specific gravity because if I see a lower USG (below 1.040), an increased BUN, and a creatinine around 1.6 or higher, I wonder about very, very early kidney disease. I wouldn’t stress about it although if you can catch a urine sample at home (the best one to get is the very first one of the morning), you can always run it by the vet and let them do a UA. Most likely, the BUN is elevated because he’s dehydrated especially if they had you pull up his food and water for the dental. Again, don’t stress that about kidney disease. It’s pretty easy to take them a urine sample; if his USG is above 1.040, he’s fine and the BUN is just dehydration. If it’s just a tiny bit below, I’d still not worry but I’d recheck his labs in six months or so.
Several things can cause elevated globulin and one of them is severe periodontal issues and since he had 18 teeth removed, that’s probably where I’d start looking at the reason. I’d just be sure it’s down the next labs you get done since labs are just a snapshot in time.