Natural toothbrush alternatives
Traditionally used "chewing sticks" found to have medicinally active properties
There seem to be three trees traditionally used as "toothbrush trees" cherished in the orient and Middle East, the Neem, Peelu and gum arabic tree respectively, which people have used to good effect even before modern toothbrushes were invented... In addition to offering an ecological way of cleaning your teeth, they also are ideal as a brush replacement when travelling etc.
Neem tree (Azadirachta indica)
People in India have chewed slender branches of the neem tree for thousands of years to clean their teeth and to this day, neem twigs continue to be sold for this use.
Products and derivatives of the Neem tree, the "tree of a thousand uses" have been used for medicinal (incl. in Ayurveda), cosmetic, agricultural and other purposes due to its antifungal, antibacterial, antiviral, pest-control, sedative and more effects. Neem extracts can also be found in Ayurvedic and other toothpastes.
Peelu, the toothbrush tree (Salvadora persica)
(aka Arak tree,
and Miswak/siwak or sewak when referring to the teeth-cleaning chewing stick or twig)
Another effective natural toothbrush prized since many centuries, the use of Salvadora persica twigs has even been recommended by the World Health Organization for oral hygiene purposes.
Scientific research such as "The miswak (chewing stick) and oral health. Studies on oral hygiene practices of urban Saudi Arabians" (see www.ncbi.nlm.nih.gov/pubmed/15224592?dopt=Abstract), "An in vitro antimicrobial comparison of miswak extract with commercially available non-alcohol mouthrinses" (see www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=16451373&query_hl=1&itool=pubmed_docsum), "Comparative effect of chewing sticks and toothbrushing on plaque removal and gingival health" (published at www.ncbi.nlm.nih.gov/pubmed/15643758) as well as "The Effect of Salvadora Persica Extract (Miswak) and Chlorahexidine Gluconate on Human Dentin: A SEM Study" (see www.ncbi.nlm.nih.gov/pubmed/12239575) shows that the Peelu tree or miswak may boast a number of medicinal properties such as being antiseptic, astringent, detergent and containing enzyme inhibitors. Analyses have shown Salvadora persica to contain, among other ingredients, much fluoride and silica1 as well as sulphur, vitamin C and flavonoids.
There seem to be several toothpastes or powders available which contain salvadora persica/miswak extracts such as Peelu tooth powder and toothpaste, Sarakan toothpaste (sold only in the UK) and likely others.
Gum arabic tree (Acacia nilotica)
aka Sant tree, Al-sant, babul, prickly acacia and Egyptian thorn, while South Africans refer to it as scented thorn or lekkerruikpeul and Australians as thorn mimosa
Thin twigs of Acacia nilotica have been used as a toothbrush in large parts of the Indian sub-continent.
Where to get Neem and/or Peelu twigs/Miswak
The internet seems to be a rich source of online sellers offering these twigs or products derived from them such as toothpaste, tooth powders and rinses containing Neem or Peelu extracts. Otherwise Indian, Arabic or other Oriental as well as health food retail stores may stock them. In fact, I saw miswak twigs offered in an "alternative health" store just yesterday (July 31, 2010) here in the midst of Berlin.
Other things you may wish to try in lieu of a man-made toothbrush
Cinnamon sticks may also work well and additionally freshen the breath.2
Sample usage instructions for miswak and similar natural toothbrushes
Chew one end of the twig until the end frays so you obtain a little "brush" with which you clean your teeth and gums (wth the fibrous ends cleaning some of the spaces in between the teeth). Cut the used end off after two weeks or so and restart the procedure until the twig has been used up. If available, rinse your mouth with water afterwards which may allow the juices extracted from the twig to help disinfect your mouth.
2 Cinnamon essential oil possesses antimicrobial properties, likely due to cinnamon containing eugenol [most famously found in cloves], an anesthetic which has local antiseptic properties.