– Dogwood stems can be used as a chew stick or toothbrush.
– Birch twigs can also be used the same way.
– Without the modern sugar-based diet, you won’t need to worry about this as much
– Paste of wood ashes works as toothpaste. Rinse thoroughly to avoid irritating gums.
– Gargle of pine needle extract (from soaking pine needles) works to freshen breath somewhat and has some antiseptic properties.
– Oak tanin (from soaking bark) is also antiseptic.
– Flossing, or more likely in a survival situation, picking your teeth is almost as important as some form of brushing. Keeping food out of the spaces between teeth as well in the hollows of molars goes a long way. Carve some tooth picks or use thorns from non toxic plants (i.e. wild roses, hawthorns)