One way to know to know when your cat needs a dental- take a photo as the cat is yawning. Of course, your veterinarian can do a mouth exam and determine if a dental is needed. Most old cats need to have their teeth cleaned. Dentals are important for the longevity of both cats and dogs. Infected gums and rotten teeth cause heart and kidney disease which greatly hasten an animal’s demise. The tartar and gingivitis are both evident in this photo of my old cat Addie. My vet did lab work to make sure she could withstand the anesthesia. Her kidneys and liver were just fine. I think Addie was 14 years old at the time of her last dental. She lived to be 18 years old.