For a toothbrush, I carry the lightest child’s size toothbrush I can find. I keep it in a plastic flip top sandwich bag. This ensures that it doesn’t get dirty, while in my ditty bag, and that it gets a little air so it doesn’t get moldy. I really miss toothpaste, when I don’t have it, so I carry a trial size tube.
I only use a little bit of toothpaste. A little bit of toothpaste does as good a job as a lot of toothpaste and I don’t have anything to spit out when I’m done — it’s considered bad form to leave toothpaste residue on the ground or on the leaves.
I have used the toothbrush/toothpaste/carrycase toothbrush. They work well and you can refill them but they are a little heavier.
I have tried the two piece ones that you connect together and wouldn’t recommend them. The brush section sometimes flings out of the handle section.
Note: The small tubes of toothpaste are often kept in the “travel size” section and not with the big tubes of toothpaste.
I carry a little transfer tube and refill my travel sized toothpaste tube with it. Here is a video I made at youtube.