I have had many problems with tartar buildup. I go to the dentist every 6 months and he wants to do deep cleaning each time. So I did some research and read somewhere that almost all toothpaste has glycerine which coats teeth and cannot be removed until you use a glycerine free product. So after some more googling I ordered natural toothpaste and my dentist was amazed I had very little tartar yesterday. I also did some peroxide + baking soda rinses a few times a month.
Just wanted to share this with everybody -- look for glycerine free toothpaste!