Here's the basic lines I use when I encounter the anti vaccine, amalgam, sealants, fluoride, root canals, etc, etc etc crowd, because I fully agree with the above posts about how the reality is you will never convince these people, regardless of how much "good" scientific evidence you show them, that their view is wrong, because after all, they tend to believe that we in the dental/medical profession are all about making money with the help of big pharma
Me: Mrs Jones, I understand that you have some concerns about the proposed treatment/materials/etc that I am proposing that we use to take care of the disease process/help reduce the risk of future disease processes in your daughter Sally
Mrs Jones: Doctor J, I read all about what you want to do on/for my precious little Sally on-line and saw a segment on Dr Oz's show recently that said that what you want to do/use will cause my little Sally to get X (insert your favorite far out disease/condition here

) I also read on some other website, since you know that I do my research about everything that I give my kids and only give them organic, fair trade products because I know that organic sugars aren't as bad for a person as regular sugar

. So I won't let you use X on little Sally, but read that if I just have her rinse with coconut oil 3 times a day and then give her vitamin C supplements that her body can fix what you say is wrong with it/prevent it from every getting that disease, without ever having to use what you propose which I heard Dr Oz say will give her Autism/Cancer/etc
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Me: Mrs Jones, I fully understand as both a parent and a clinician, the concerns that you have about doing what is best for your child. There is so much information out there on the internet that can even make it seem at times that drinking a simple glass of water will likely lead to imminent death! I can assure you that I have done a wealth of research based on peer reviewed, reproduceable studies about all the materials that I use in my office, and feel very comfortable about using them on/in/for my patients and my own family as well. That is how I choose to operate my practice. If this is something that you have some concerns about, I would be more than happy to forward your records to another office of your choosing.
Lesson to be learned, you will never be able to connect with some patients, so don't get offended if you don't. Just learn to politely encourage them to seek care elsewhere, as long term your sanity and blood pressure will be much better that way!