Quote (Thor123422 @ Aug 3 2018 04:58am)

They have studied dietary versus topical application and found topical doesn't get all of the benefits.

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Most of the ingested fluorides reach the teeth via saliva, whose fluoride content varies from less than 0.01 to 0.05 ppm. Fluoride absorption in bones and teeth decreases with increasing age [15]. It is widely accepted that fluoride only helps prevent dental decay by topical means—by direct action on the tooth enamel predominantly after eruption and dental plaque [16, 17]

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Early support was based on an assumed systemic role of fluoride in reducing decay [3, 4]. However, later studies have shown that the differences in fluoride concentration in surface enamel between permanent teeth from areas with no fluoride or low levels and fluoridated areas were minimal and support the fact that effect of fluoride is almost exclusively posteruptive and topical rather than systemic challenging claims made for water fluoridation's efficacy [23–25].

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This paper discusses two paradigms central to cariology. The first concerns the most successful caries-preventive agent: fluoride. When it was thought that fluoride had to be present during tooth mineralisation to 'improve' the biological apatite and the 'caries resistance' of the teeth, systemic fluoride administration was necessary for maximum benefit. Caries reduction therefore had to be balanced against increasing dental fluorosis. The 'caries resistance' concept was shown to be erroneous 25 years ago, but the new paradigm is not yet fully adopted in public health dentistry, so we still await real breakthroughs in more effective use of fluorides for caries prevention.

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In this updated review of the pre-eruptive vs. post-eruptive benefits of fluoride in the prevention of dental caries, a re-examination of the literature, which is often cited to support the notion that swallowing fluoride, either in water or in pill form, was done in recognition of the mounting evidence for the topical mechanism as being the primary mechanism for the prevention of dental caries. Maximum benefits from exposing newly erupted teeth to topical fluoride in the oral cavity may have been seriously under-estimated. This has obvious implications for the use of systemic fluorides to prevent dental caries and forces everyone working in the field to examine more closely the risks and benefits of fluoride in all its delivery forms.

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A dogma has existed for many decades, that fluoride has to be ingested and acts mainly pre-eruptively. However, recent studies concerning the systemic effect of fluoride supplementation concluded that the caries-preventive effect of fluoride is almost exclusively posteruptive. Moreover, epidemiologists have cast doubt on the validity of the 'old' studies dealing with fluoride use. The concept of the posteruptive fluoride effect is supported by in vitro and in situ investigations demonstrating that the mode of action of fluoride can be attributed mainly to its influence on de- and remineralization kinetics of dental hard tissues. Therefore, topical fluoride application (e.g. in the form of fluoridated dentifrices) should be encouraged.

Quote (EndlessSky @ Aug 3 2018 04:47am)

There was never a reason to put fluoride in the water in the first place.

The only reason it happens is because its a cheap way to get rid of uranium processing byproducts.