Consider a 10-day trip without resupply. A bathroom is not exactly available next to the campfire. What would be different about brushing teeth: frequency, tool, etc.?
Those are some of the problems I have encountered and solutions which have worked for me.
P: Water is scarce.
S: Brush, spit (profusely), rinse, spit, rinse, spit. This amounts to only 2 small gulps of water - as little as 100ml.
The brush shake hard, rinse lightly, shake hard. That gets the toothpaste residue off.
by @Chris H
Sacrifice a small squirt from a bicycling bottle to give the brush a very rough rinse.
P: Batteries are scarce and in the dark the toothpaste drops to the ground.
S: Squirt the toothpaste into your mouth instead of onto the toothbrush. Soon you will learn to measure the correct dose. And will obviously never drop it.
P: A toothpaste weighs a ton.
S: Purchase a tiny package or carry a nearly empty one.
P: I forgot my brush. And paste.
S: Chew some tough grass or young branch to make it into a brush. Use it to remove food in between the teeth. Never forget again as 10 days without tooth care is too much.
P: My brush is wet, it's gonna rot.
S: Dry it at the rest/dry/eat session at lunch.
My go-to solution for backpacking teeth brushing is to use baking soda.
- odor-free, so you don’t have to worry about treating it as a smellable
- extremely light, as it is a powder
- does actually work
Some cons are the taste and texture which aren’t great, and it may not be ideal for long periods of time (as fluoride is good for teeth health). However, for a week or two, a little container of baking soda is great.
I store it in something like this:
Image courtesy of Amazon, no affiliation.
The container solves most of the cons of trying to bring baking soda as a powder. The little spout dispenses the powder directly onto the brush, and then you can use it like normal.
And if weight is really critical, you can actually cut your toothbrush handle off, most of the way up. All-in-all, lighter than regular toothpaste, and odor-free, which can be of concern in many areas.
I'd take a toothbrush (cut the handle down for easier packing if space is tight) and a small tube of toothpaste, to be used sparingly, about half as much as at home.
You can also brush your teeth without toothpaste, but with a brush. This might be a good idea in the most sensitive areas if you don't want to dispose of toothpaste in a hole in the ground. For occasional use you can swallow a little bit.
Rather than pouring water onto the brush if fresh water is scarce, I take some water into my mouth and wet the brush with that, having applied a smear of toothpaste to it first.
In more highly travelled areas, a little toothpaste is insignificant so I tend to spit the toothpaste into a hole in the ground (well away from water of course) then cover it up. The spat out toothpaste can be diluted/washed in with water (not necessarily clean) or by urinating on the mess on the ground.
While I can sometimes find tiny tubes of toothpaste, they're overpriced and wasteful, so I only use them if space is at a real premium. Instead I save the end of a tube for travel (hiking, bikepacking, or motorised travel).
I always take a toothbrush backpacking and brush twice a day. If space and weight are absolutely critical you can cut a length off the handle and have a half-length but useable toothbrush.
I once tried 3 days without brushing and it was pretty grim. I wouldn't go 10.
Toothpaste is not necessary for 10 days (arguably not necessary at all) - brushing without toothpaste does a perfectly good job of removing food, and solves the problem of how to carry toothpaste, where to spit it, etc.
If it makes you feel better, also use a small toothbrush or one of those tiny brushes (praxi brushes?) that easily get into the spaces between teeth. You can forget about toothpaste. Your teeth can survive just fine without toothpaste for 10 days. Longer. Swish water around your mouth after eating, and swallow it.
But, do not worry about spitting out food and plaque particles on the ground. You pee much more volume than you spit.
If you are uncomfortable when you are not squeaky clean, just concentrate on what a marvelous treat your first shower and first vigorous brushing will be. Homo sapiens went through a couple of million years of evolving while dirty. You can be dirty for 10 days. (Although I admit, I would go crazy if I did not wash my hair at all during a ten day trip.)