The only product I have used with some success is the CET Aquadent. It did prolong the time for a couple of my pups' dentals. Most of mine need dentals yearly and I found that when I used that I was able to push a couple into 18 months.
Please note that it has xylitol which has caused some people on this forum to say it is unhealthy. I did speak at length with my vet and telephoned the company. They also consulted with my vet and then sent me the paperwork I had requested regarding the amount of xylitol in this product. My conclusion
for my pups is that it is safe to use.
Virbac Animal Health | United States ? C.E.T. AQUADENT® Drinking Water Additive
I have never seen that chews have changed anything...my opinion is that brushing of the teeth is probably the best thing; but even that does not prevent the need for dentals.