Reality is that the 3-1-1 Quart bag rules is a game, especially lately - going thru certain US airports at peak time, it's a matter of going thru the motion. Laid them out neatly on top of shoes, laptops & jackets - zipped straight thru to the other side of the conveyer belt.

I've seen 4 oz. items going thru as part of a stuffed ziplock bag, no questions asked or visual exam; and, for something like toothpaste, it's pretty normal in size.

AquaFresh has 100 ml (3.38 oz) for sale at places like Walgreen or CVS here in the US, might have to check local stores for availabilities. Unit pricing for those tiny travel sizes are truely ripoffs.

The tiny single-use Colgate toothpaste are cute, I collect/save them at hotels that offer it and travel with them - heck with being green or reducing carbon footprint, it's the war theater on terror. Think of the tens of thousands of bottles dumped into giant 55 gallon drums everyday at airports, wasted.