crowns are not as bad as root canals. just be sure the Amalgam is removed before its capped. also, the composite material can contain FLUORIDE! diamond lite or diamond crown is the way to go. you may also be able to talk the dentist into trying a filling first. composite can be used in big fillings. its your money.
but for now you dont want to detox. 4 drops is fine. breath in through the nose, out through the mouth. avoid hot food and drink. avoid much chewing, as that creates heat and increases outgassing by many factors.
raw juicing with plenty of greens. and of course you will crave stuff. and above all, relax and thank god for your blessings. sing to your baby. they love that.