I have used Petrodex Enzymatic Toothpaste (beef or chicken flavor) for 5 years and my 4 & 5 year old yorkies have never lost any teeth. I have their teeth cleaned professionally, every few years. I use a little child's toothbrush.
Most of the time I brush every other night, then sometimes every night. Maybe I have doggies with genetically good teeth. But the Vet says I do a pretty good job.
I can't imagine brushing them twice a day!
Thinking about buying some of the 'Drs. Foster and Smith Dental Clens Pads for in between brushings.