Q. Do not know about his teeth but his breath is bad
A. Small dogs often develop tartar on their teeth, causing bad breath and inflammation of the gums. Your dog needs to have an exam with your vet to determine the cause of the bad breath. If it is indeed bad teeth/dental disease, he will also need bloodwork to determine his ability to handle anesthesia. If his bloodwork is good, he should have a dental cleaning and possibly extractions. Leaving his teeth as they are means that the inflammation and infection causing the bad smell will continue, and the bacteria in his mouth has a direct route to infect heart valves, a condition called vegetative endocarditis. Most dogs recover quickly and do great after a dental and extractions and live longer, healthier lives as a result.
A. Bad breath is often caused by bad teeth or an infection in the mouth. I'd suggest a dental exam by his veterinarian. Small dogs often suffer from dental disease and require early dental care and cleanings.