I would tell you not to brush twice a day. If your dog already has a lot of build up, tarter, and plaque he may need a dental cleaning from your vet to get all that off his teeth.
Good quality dry food will help break off the palque and tarter, as well as chew toys, bones, pigs ears, greenies ( my dog gets these once every couple months or so)
Fiona is 11 months old, and I have not brushed her teeth at all, they are gorgeous!
I would just tell you if they are that bad, brushing and chew toys will not get rid of the build up, and your more than likely going to need to get them done at the vets.
Good Luck
