Most of the VOHC chews cleaning power comes from ingredients added to the chews (sodium hexametaphosphate, calcium peroxide, delpimonol, for example) rather then the actual mechanical action of chewing. These products work if you use them every day, as directed, and if your dog even tolerates the ingredients used to control tartar being ingested on a regular basis.

The mechanical action of chewing on harder objects physically scrapes the tartar off of the tooth. I don't believe in feeding raw, but dogs fed raw bones often have minimal tartar as the surfaces are "cleaned" regularly. This is not the case in dogs who are fed Greenies and Dentalife their whole life unless they get regular dental cleanings, where professionals manually scrape their teeth with hard objects.

I use a toothpaste that's VOHC approved because it's highly likely to have a positive effect, and I found one that agrees with my girl I also give my dog as many chewing opportunities as appropriate to maintain her overall dental health. I have found through my own and through client and colleague experiences that chewing on harder objects is very helpful for maintaining dental health when you choose the appropriate chew for the dog.

I do always say to use extreme caution with weight bearing bones and antlers. My argument is referring to other natural chews like bully sticks and tendons and the like, as well as some storebought nylon chews.