I read the same recipe - baking soda plus coconut oil - sonewhere else on Steemit and I am testing it. Will send you the link.
First days of use: uncommon taste but it works. I used a toothpaste with baking soda as an ingredient before - so the difference cannot be that big. However, I try to use less chemical components in daily life and enjoy using this mix for cleaning. I add baking soda and sea salt to my bath, too.
Several times I read that kurkuma can be added to the selfmade toothpaste and is helpful to brighten your teeth.
Advise, however, for persons wearing a tooth provisorial (not ceramics): Your provisorial turns yellow and it is tought to bleech with some bleaching toothpaste afterwards. Better no use while havin provisorial teeth!