actually fluoride topically applied as in toothpastes is great for remineralizing the teethwall.
all the research about fluoride being bad only applies to the water and other overconsumption of fluoride. sometimes 'alternative' tends to take things a little bit too far.
i started using half my brain capacity and realized only ingestion can cause fluoride toxicity. and no, maybe apart from children who tend to swallow ingestion doesnt happen while brushing. and toxicity neither. if that would be the case, then only from water and/or other sources (tablets whatever)