What do you think about chocolate toothpaste? It's exactly the bitterest chemical found in chocolate, theobromine, which encourages the fight against cavities.

This chemical, a molecule similar to caffeine, is also a stimulant.

Preliminary tests revealed to a Tulane team that this chemical is more efficient than fluoride in strengthening the crystalline structure of teeth against erosion by acid-producing bacteria, linked to most tooth decay.

"Since tooth decay is the most preventable disease still plaguing humankind, the findings are potentially quite important. Moreover, the last half-century has witnessed "little to no innovation" in cavity-fighting additives for toothpastes." said lead researcher Arman Sadeghpour.

But pure chocolate won't work: its sugars boost the tooth decay bacteria while the fats that give the chocolate its creaminess are not desirable.

Theobromine is 3,7-dimethylxanthine while caffeine is 1,3,7-trimethylxanthine; this means they are basically the same compound, only that caffeine has an extra methyl group (a carbon atom with three hydrogens attached).

"But the subtle structural distinctions between these two xanthines account for their profound physiological differences. Whereas caffeine may harm bones and teeth, theobromine appears to bolster both structural materials," said Sadeghpour.

Teeth and bones are continually demineralizing and remineralizing on a microscopic scale.

Sadeghpour cut into pieces leftover human molars from 13 individuals and applied on those pieces variable doses of fluoride or theobromine. After all the molar slices were inserted into a machine with a diamond bit, that pressed for 5 seconds, inducing an indentation, the depression's size permitted to assess a tooth enamel's hardness.

In all tests, theobromine was better than fluoride. In other tests, Sadeghpour covered all but a tiny portion of each piece of tooth exposed overnight to solutions of fluoride or theobromine.

The next day, the treated tooth surface was kept for 10 minutes in strong acid: the theobromine-treated teeth had kept 8 % more calcium than fluoride-treated teeth.
The team is going to check if theobromine is also efficient in real-life conditions: exposure to the cavity-producing bacteria encountered in our mouths.