Ingestible toothpaste was one solution to the problem of spitting and was developed by Dr. Ira Shannon of the Houston VA Medical Center. The product called NASAdent was a foamless toothpaste that could be swallowed.
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Back in the 1960s, NASA worried that their moonwalking employees wouldn’t be able to maintain their dental hygiene. As a result, they developed a foamless, ingestible toothpaste called NASAdent. – Tiny Fox Lab Facts

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Source: ntrs.nasa.gov/citations…