My two year old guinea pig, Joey, has been struggling with dental issues. I adopted him from a rescue, where he was born, and unlimited hay has always been available. Joey has always eaten it, but never as much as his partner, Calvin. After noticing his weight was dropping and eating seemed to be a challenge (often dropping pellets from him mouth while eating, difficulty eating vegetable and hay), I immediately took him to the vet. Initially, the vet trimmed his incisors which didn't seem to solve any issues. The following week he began drooling and his molars were then filed. The vet found that his molars were pinching his tongue, causing him trouble while eating. Soon after the filing, Joey began to willingly eat critical care from the syringe (rather than force feeding) and was able to eat raspberry and banana (only given in small amounts because of the high sugar levels). Still unable to eat pellets, hay, or vegetables, I took him to the vet the next week and was given an anti-fungal antibiotic, thinking there may have infection in his gums causing him to stop eating (leading to the overgrowth of his molars). Two days after taking the antibiotic, he was able to eat pellets on his own and he began to come out of his igloo more often and seemed to have a lot more energy. After we had finished the antibiotics, we went to the vet again and he trimmed his incisors again. After a day or so, Joey was able to eat vegetables and fruits when cut into tiny pieces. Throughout this whole process Joey has consistently tried and tried again to eat. He has continued to come out when I put fresh hay, veggies, and pellets in the cage (though he can't eat hay and only can eat vegetables when cute in extremely small pieces). I went on vacation for a week and dreaded leaving him with anyone, but luckily found an volunteer at my local guinea pig shelter who was very experienced with dental problems in guinea pigs and hand feeding. As the week went by, she got him to eat a little hay and managed to get his weight up to 710 grams (which his huge because when I first dropped him off he weighed 654 grams)! She called the vet while I was gone, who recommended flushing out the saliva in his mouth. This decreased the amount of drooling, but he still continues to do so. She recommended not feeding as much critical care and feeding more veggies, once I did that his weight dropped. The volunteer who watched Joey wrote down the feeding hours and how much she fed (though it fluctuated). He is currently eating cucumber, red pepper, radish, watermelon, apple, lettuce, and cilantro when cut up small. With these vegetables, I have continued to feed critical care, but it is difficult to know how much because he loves it and would eat as much as I give him (I don't want to over feed). After weighing him this morning, his current weight is 644 grams. Though it varies, I currently feed him about 12 cc/mL per sitting (about 4-6 feedings per day). Is there anything else I should do about his drooling? How much critical care should I feed? Should I take him back to the vet? Any advice is greatly appreciated and sorry for the long post! And yes the vet I have taken him to is experienced in dental problems in guinea pigs