You should take him into your vet for a dental cleaning. My vet (who is my boss as well) generally recommends annual dental cleanings after the age of 3 yrs. At the clinic I work for, a dental on a dog of that estimated size generally costs between $85 - $98 including polishing, anesthesia, anibiotics, and mouth rinse. (Extractions are extra if needed and prices vary depending on which teeth and how difficult the extraction is) Everything we use with our dentals is human grade. They are the same scalers and polishers your dentist uses on you. It's REALLY worth having done as tarter build up can lead to periodontal disease, gingivitis, abcesses, and kidney and liver problems. An ounce of prevention is worth a pound of cure.