Dental disease causes chronic pain, non-specific ill-health due to bacteria entering the bloodstream, serious and potentially fatal heart and kidney disease due to bacteria infiltrating those organs. It is the single most ignored health issue by owners. I have even had a client die of pneumonia caused by bacteria that originated in his dogs' (filthy) mouths, sadly after his wife had declined dental care for the dogs.
You are unlikely to know if your dog is in chronic pain, as they accept it, and will continue to do their best to eat and get through life.
It is not possible to adequately examine or clean teeth without general anaesthetic in an animal. Groomers who are offering this half-baked attempt at a cosmetic clean-up are doing a grave disservice to the dog and the owner.
All small breed dogs are likely to need annual dental cleaning under anaesthetic from the age of about 8.
As vets, we only remove decayed, loose or broken teeth. If teeth are decayed, broken, or loose, your dog will be far more comfortable without them.
Dogs can eat very well with few or no teeth, as long as the teeth that they have are not diseased.
If you teach your dog to accept having his teeth brushed, you will be able to maintain very good dental health. 2 minutes a day will be more than enough. However, brushing cannot remove tartar. Dental descaling is needed for that.
All that chews or bones will do is to randomly crack or wear off some tartar deposits. Equally, bones can break teeth.
Gels and rinses do little to improve dental health.