§ Mr. Rankinasked the Secretary of State for Scotland what research he is conducting into the value of zirconium as a preventative to dental decay in children's teeth; and to what extent the results show that it is more efficient and less harmful than adding sodium fluoride to drinking water.
§ Mr. RossNone. I understand that work on this substance in the United States is still in a preliminary stage and that no scientific evidence has been published about it. I do not accept the suggestion that the addition of sodium fluoride to drinking water to provide a concentration of one part per million is in any way harmful.