What exactly is regular cider vinegar ??? no clue.
A second option IMHO could just be lemon juice. Un sweetened, you want no Sugar - no glucose, no fructose no lactose no-ose.
I've used lemon juice and acv to good effect, just brush your teeth 20-30 min after it, that's it. It can be a bit hard on your enamel.
Thanks.
Srinath.