By Mistress Jadwiga Zajaczkowa
Excerpted from: A selection of Dental hygiene and mouthwash products from a variety of medieval and Renaissance sources.
Despite modern ideas to the contrary, people in the middle ages did spend time trying to take care of their teeth and combat bad breath. Dental care prescriptions I've found seem to center around rinsing the mouth, often with an acidic substance (wine or vinegar), though sometimes with a caustic. Teeth were rubbed with a cloth, and/or with mixtures of herbs and/or abrasives. Toothsticks, toothpicks, and rubbers of various kinds are documented in books and archeological sites. Some products, such as the bay leaf/ musk combination and the pills of spices, provide a good smell; though spices also were used to heal infection. The common and repeated ingredients include wine, salt and mint; alum and abrasive materials are included frequently in other recipes. I would say that for SCA use, the sage/salt tooth powder and the mint-vinegar rinse, along with rinsing with clear cold water, would be the best and easiest to use.
Water Rinse--Hildegarde of Bingen, Physica, 1158 (German)
"One who wishes to have hard, healthy teeth should take pure, cold water into his mouth in the morning, when he gets out of bed. He should hold it for a little while in his mouth so that the mucus around his teeth become soft, and so this water might wash his teeth. If he does this often, the mucus around his teeth will not increase, and his teeth will remain healthy. Since the mucus adheres to the teeth during sleep, when the person rises from sleep he should clean them with cold water, which cleans teeth better than warm water. Warm water makes them more fragile." (Book 2, Section 2]
Mint mouthwash--Bankes' Herbal, 1525
"For the stinking of the mouth and filth of the gums and of the teeth, wash thy mouth and gums with vinegar that mints have been sodden in; after that, rub them with the powder of mints or with dry mints."
Fill a pint jar with mint sprigs, pour your favorite vinegar overtop. Allow to soak at least overnight, if not longer. For use, the vinegar is poured off and used to rinse the mouth.
Mint's action against halitosis and indigestion was well known to period herbalists and appears again and again. It's also associated with eating, as in Ovid where someone rubs the table with the herb before setting the table for dinner . You'll want to rinse with water afterward, though.
Sage tooth whitening scrub--Gervase Markham, The English Housewife. 1615
"For teeth that are yellow: Take sage and salt, of each alike, and stamp them well together, then bake till it be hard, and make a fine powder thereof, then therewith rub the teeth evening and morning and it will take away all yellowness."
60 fresh (small) sage leaves
2 tablespoons sea salt
(You want equal weights, not volumes, of sage and salt, and it must be fresh.)
Beat the sage leaves into the salt in groups of 10-20 leaves, adding sufficient leaves to form a rather dry paste (use a mortar and pestle or a food processor). Spread on a baking sheet and bake for 20 minutes in a 300 degree oven, until it forms a hard crust. Leave it in the oven overnight to dry, crumble it up, and stored in a moisture-proof container.To use, rub on with a damp finger, linen square, or toothbrush; rinse mouth out after using.
Belief in sage's antiseptic and healing properties is cited in Banckes' Herbal: "It will make a man's body clean; therefore who that useth to eat of this herb or drink it, it is marvel that any inconvenience should grieve them that use it."
Salt is one of the common alternative tooth brushing powders suggested in modern texts, and its granular nature would help polish the teeth. The chlorophyll in green herbs such as sage freshen the breath.
An Herbal  Also known as Banckes' Herbal. Author unknown, published 1525. Facsimile/transcripted edition, ed. by Larkey & Pyles. (NY: Scholars' Facsimiles and Reprints, 1941)
Hildegarde of Bingen. Hildegard von Bingen's Physica:
the complete English translation of her classic work on
Health and Healing. Trans. from the Latin by Patricia
Throop. (Rochester, VT: Healing Arts, 1998).
Markham, Gervase. The English Housewife: containing
the inward and outward virtues which ought to be in a
complete woman., first printed 1615. Published 1986
by McGill-Queen's University Press, Montreal; edited
by Michael R. Best
Reprinted from the Fall, 2005, issue of Arts and Sciences, a special issue of the Pikestaff,
the official newsletter of the Kingdom of the East. Used by permission.