To make your own tooth powder or paste, the basic rule would be to simply be creative.

You can mix in, at the proportion of your choosing, any of the ingredients[1] mentioned under Toothpaste Alternatives, as well as others such as borax powder[2], therapeutic essential oils,  MSM (which not only helps to fight infection and pain but also to whiten teeth) and many more.

For "herbal" inspiration have a look at Herbs for strengthening teeth and gums and Gum home remedies and therapeutic mouthwashes to see if any of the listed plants could be helpful for your specific needs. Then grind them into a fine powder, use as essential oil etc.

Personally, I make use of surplus or old kitchen spices and herbs by adding them to my self-made tooth powder or paste. As long as I add xylitol or erythritol or some other tooth-friendly sweetener, it always tastes good, and most all herbs and spices have some beneficial medicinal property.

Note: Most of the following recipes actually have therapeutic qualities, so for maximum benefit allow them to sit on your teeth for several minutes before rinsing your mouth.

Sample recipes DIY toothpaste or powder

Self-made toothpaste based on healing earth (white clay), bentonite or other medicinal clay

Medicinal clays help draw toxins out of the body (and mouth if used for brushing) and thanks to their varying mineral content, should also help to some extent in remineralizing the enamel.

If available, use clay that has been very finely ground (ultrafine). This type is easier on the enamel than for example whiting or whitening (chalk powder) which is popular in England as a tooth powder.

Sample recipe number 1

Mix c. 100 g of white clay with boiled water and a pinch of sea salt (adding the water in drops!) until you have a cream-like consistency. Add c. five drops of tea tree or peppermint oil. They are bactericidal and prevent bacteria from breeding in your toothpaste. Nevertheless it's best to only prepare small amounts of this toothpaste.

Regarding white clay, Annie Karl wrote to me that she "was informed by an intuitive healer, several years previously, that white powdered clay and calcium fluoride (tincture) will rebuild bone tissue, including tooth bone. I was informed by another intuitive that brushing the teeth with white powdered clay will make the teeth stronger and more resistant to decay."

Sample recipe number 2

Mix one third cup of bentonite clay with a quarter cup of boiling water until you have a cream-like consistency. Allow to cool, then add a tablespoon of virgin coconut oil (for the reasons compare further below), some high-quality sea salt (such as a quarter teaspoon) and for a sweet taste, some tooth-friendly xylitol and/or stevia[3] and finally some twenty or more drops of any essential oil or combination of oils you like.[4]

Self-made toothpaste based on activated charcoal

Sample recipe number 3

Mix 2 parts activated charcoal with 1 part licorice root, add a pinch of  bentonite clay and several drops of essential oil of orange to taste.

Self-made toothpaste based on virgin coconut oil (VCO)

A powerful germ fighter[5], virgin coconut oil can beautifully replace the somewhat controversial glycerin[6] as a basis of self-made toothpaste.

Add for instance some natural antimicrobial flavouring agent (such as essential rosemary oil), xylitol and baking soda, and you have a delicious toothpaste look-alike which is super healthy for teeth and gums and lasts "forever".

Sample recipe number 4

Mix 1 tbs of coconut oil, 1 tbs of turmeric, 2 drops of oil of cloves, a pinch of sea salt. Stir well.

General

Feel free to add finely ground minerals and trace elements to any self-made toothpaste or powder. This could be anything from very finely ground eggshells and/or seaweed[7] and various types of medicinal clay to colloidal mineral drops.[8]

Make sure to mix the ingredients of all the above recipes well and store your DIY toothpaste in a glass or mason jar (not in plastic since essential oils will "eat into" the plastic).

Footnotes

1 Baking soda would be a favourite, compare Baking soda as tooth powder for cleaning teeth.
2 Borax is one of Dr. Hulda Clark's favourites for non-toxic cleaning around the house. One person wrote that she mixes borax powder with baking soda in equal amounts which makes her teeth and mouth feel very clean, with the added bonus that the borax also helped with her candida.
3 For the tooth benefits of stevia, see Best tooth-friendly sugar substitutes) .
4 See essential oils for inspiration and background information on how to choose and use them.
5 See Another tooth-friendly oil? Virgin coconut oil.
6 Compare Dental health prerequisite number 7) .
7 More on integrating eggshell (and seaweed, respectively) into your tooth-friendly regimen under Foods rich in minerals & trace elements.
8 Compare Products for strengthening teeth and enamel, reducing cavities and sensitivity.

More on dental care