Deninger proposed that inadequate fluoride nutrition contributed to defective tooth enamel, described his calcium fluoride supplementation experiments, and acknowledged that his few examples were not conclusive.
Please see also the German essay about Albert Deninger by Peter Meiers:
- Meier P - "Albert Deningers Calciumfluorid-Experimente" (2011, 2016)
http://fluoride-history.de/Deninger.pdf