There has been many more studies on fluoride, none of which have shown that that the low concentrations of fluoride added to drinking water has any negative health effect.
Again, there have not been any randomized control trials testing the efficacy of fluoride in drinking water compared to other delivery methods.
It depends on the area you're dealing with. In some countries, it's more cost effective to put fluoride in the water supply, while in others, fluoride toothpastes are more effective. In Germany, they put fluoride in iodized salt!
Did you just not read my comment? The reason isn’t cost, it’s not that expensive to add fluoride.
The reason is we wouldn’t be adding anything to drinking water if there were better alternatives. If we started again with today’s standards, no scientist would recommend fluoridated drinking water.