Hi there...you are such a good pet parent to be thinking about your little dog's teeth! Many owners simply tolerate the tartar and bad breath, which is not a good thing for their dogs!!
Our dogs (like us) get a buildup of plaque on their teeth from the saliva, food particles, immune cells and bacteria. Often, this plaque is worse on the big canine teeth in the front and the big cutting, carnassial teeth near the back of the mouth. If the plaque matrix is not disrupted within about 48 hours, it will organize and become tartar. The tartar then protects the bacteria as they eat away at the bone underneath the tooth. SO...if you can mechanically stop the plaque from organizing (sounds like a union problem, doesn't it? :-)) you can help lengthen the time between dental cleanings.
The best way to do this is by daily brushing. As your little guy is a little older, he might not tolerate it as well, but you can try to teach him to let you brush his teeth by starting with a gauze pad wrapped around your finger (maybe use some beef broth to make the experience more "fun"), then try graduating to a soft bristle tooth brush and a pet dentifrice. Don't use human toothpaste ever!!
As Purduegirl said, T/d is also a good option either as his sole diet or as treats. The mechanical action helps disrupt plaque better than most dry kibble. Flat rawhide strips are also recommended.
You can find good chews, food and toys by looking for the Veterinary Oral Health Council (VOHC) seal on different pet dental products.
Finally, (sorry for the length of this), ask your veterinarian about a product called Oravet. It's a barrier sealant that the veterinarian can apply after the next cleaning and then you apply weekly after that. The sealant helps to prevent plaque from forming and can really help stretch out that time between dentals.
Teko: I hate to disagree, but a lot of veterinarians would not appreciate your advice about neck bones. Many pets get tooth fractures and even GI obstructions from chewing on bones.
Good luck!
There is Prescription Diet food that is specifially made to help keep teeth clean. I believe it is T/D but your vet will know for sure. It's not exactly cheap, but I would imagine he doesn't eat a ton. In addition to the chew bones and things like that, try to avoid giving him soft foods and table scrapes, as these can increase tartar build-up.
I know getting his teeth cleaned isn't cheap, but it is necessary, and tartar/tooth decay is also strongly linked to heart diease. So by giving him clean teeth, you are not only making him more comfortable, as decaying teeth and gingivitis is pain, you can also add to his life by helping to prevent heart disease.
I give my dogs a neck bone from time to time. They do not splinter and they have to really chew and chew to break em up. But, it has to be neck bones and no other kind. In a dogs world, the bones and occasional raw meat clean their teeth. I went thru the cleaning thing with my last one and have been researching it.
Dogs need to have their teeth cleaned every couple of years. Chewing bones helps break off the tartar but once you have had his teeth cleaned try using a rubber finger tip tooth brush available in most pet shops. I'd also look for a new vet as in California we pay about $120, but the cost of teeth cleaning is more complicated as the dog must be given anesthesia