Ah, so you're a troll. The study I linked showed multiple countries with 40-50% reduction in tooth caries and you've linked to a publication called the Durango Herald.

Have a good day. I hope that other folks who read this don't try to harm our communities with disinformation like this. I'm sorry that you don't seem to be able to understand balance.

(ETA: the guy who wrote the editorial is a gym owner in that area who sells a lifestyle fitness book called Wellness Toolbox. He has 28 years as a fitness instructor. His biography says nothing about him being a dentist or flouride expert of any kind.)

You said you are an engineer and bragged about how smart you are, so I assumed you know how to do research. I'm not going to link every study out there. They are there and available. They do show high levels can be toxic, as with anything else. They also show appropriate levels save communities from tooth decay and the long-term issues those carry. I had faith that you know how to determine if a source is valid, and could do that on your own time. You can even go talk to a dentist and ask them for studies! They are a great resource, and I bet many of them would love to give you that information. I bet even a PCP office could point you in the direction of studies about the dangers and benefits of flouride.

Here's one for example, that explains how appropriate levels have helped and caused no harm. You being an engineer doesn't mean you aren't susceptible to disinformation campaigns. All of us are vulnerable to that sort of messaging, intelligence has nothing to do with it. Ignorance does, not being cognizant that there are people on TV and selling newspapers that have a vested interest in convincing people to harm their own communities and weaken their safety. Creating a bunch of tooth decay where none need be because you are not willing to read multiple sources on your own time and discern which ones are valid and which aren't, is a very weird behavior, to be honest with you.

Flourosis is a real issue, and it naturally occurs in waterways. We also use methods to control that. If we didn't have studies we wouldnt know that information either. We also know the lowest level possible to not cause harm and reduce dental issues in entire communities.

"To minimize fluoride toxicity, the concentration of fluoride in drinking water has been controlled to attain the recommended level of 0.8~1.0 ppm (13)"

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6195894/

So we use our water to brush our teeth, and ingesting it doesn't have any harmful outcomes. If you read the article, one of the people who sounded the alarm was a dentist who saw people from a single town coming in with tooth decay issues at a greater rate than everyone else. He harmed people for years, your teeth are extremely important. I don't even get why so many people are hung up on that specific thing, when no studies show harm from ingesting normal amounts (remember, if you ingest higher than your UI of vitamins you can leach calcium from your bones and get ulcers, too much anything, even natural things we need can cause harm, so this is not flouride specific.) We don't need to show ingesting it is positive, we already know it's neutral and that using it to brush teeth is a net positive for the entire community. flouride isn't a vitamin, you're not taking a One A Day here.

My best guess is that this question "is flouride safe to ingest? Show me a study!" Is a direct feed of propaganda, since all of the deniers are asking it in exactly the same way. Mainly because there are many many studies already available that show you that flouride levels in town water systems are regulated to be under that amount already. This man did know that, and he damaged people's teeth, he damaged children and teenagers teeth for the rest of their lives without them or their parents knowing and you're here making weird false claims to try and justify this. You should, and the others, should really evaluate why you think it's appropriate to lie to people and give them life-long issues that impact every aspect of their health. Eating, using your teeth, having healthy teeth, is far far more important than this ridiculous assertion that we need to learn something that doesn't make sense and is already proven