I used Dentabits for a few years on my cats and they (IMO) did absolutely nothing! Both Tibby and Molly ended up having to have dentals and extractions at 2.5 years old
Although brushing may be difficult at first, it really is well worth persisting! It is simply the best thing you can do to maintain their dental health.
If you buy some Logic toothpaste from your vet, you can use it on a toothbrush to brush their teeth, OR you can smear it onto their paw for them to lick off!