and despite the higher pricing , arm & hammer - nothing to do with the legendary oil tycoon armand hammer until he ended confusion by buying a small stake in church & dwight in 1986 - still commands a 63.5 per cent share of the total baking soda dentifrice market , although its sales growth rate over the past six months of about 20 per cent has been below that of baking soda toothpastes generally .