I will compare the "spiritual phude" the Washtowel Slaveholdery serves to spiritual fluoride--which CAUSES cavities. And that's all you are getting--fluoride. The tooth contains several different minerals--calcium and phosphate are the two major ones. There are three different forms--one each with hydroxy-phosphate, one with chloro-phosphate, and one with fluoro-phosphate. The majority of the stuff in your teeth is calcium hydroxy-phosphate. This stuff is strong but susceptible to acid attack (the hydroxy-part is ruined by being turned into a water molecule in acid). Chloro- and fluoro-phosphate is more resistant to acid. However, calcium fluoro-phosphate, despite being resistant to acid, is brittle. This stuff can actually cause cavities that manifest themselves as breakage of the whole tooth, often without warning. Hence, the balance between the three forms.
What the Washtowel Slaveholdery provides is the fluoride. Which alone does nothing. Even embedded in the tooth, too much fluoride can make your teeth brittle. Too much spiritual fluoride can do the same thing to whatever faith you may have had--too much of the shame and guilt can make the congregation as brittle as a tooth composed of mostly calcium fluoro-phosphate. It can also make your faith brittle--which is why they are so paranoid about reading apostate materials.
At least the dental clinic provides other services. Even if you don't get any fluoride, you are going to get a good cleaning. If your teeth get too much tartar buildup and you do not take care of it, it can ruin your gums. If they get infected, you not only lose teeth (that might be perfectly sound), but you risk getting other infection. And if you happen to have tiny cavities, you can at least be alerted that there is a potential problem so you can take steps to fix them or at least prevent them from getting worse. If you have big cavities, you can get them fixed before the whole tooth breaks and leaves you with a toothache. Try that with the Washtowel "clinic".