In the early 1900s when I was a child growing up on the working class Huxley housing estate of Victorian-style terraces, everyone I knew cleaned their teeth with salt, which was of course mildly abrasive and was also said to kill germs.
I understand from a retired pharmacist that it was quite common to use twigs of wood as toothbrushes. A twig was cut to expose the soft interior and the outer bark was peeled back slightly. The exposed end was then rubbed onto the teeth, which made it divide into fibres which served as brush bristles. Willow was apparently particularly suitable, although certain other woods could also serve. Presumably the practice was only common in rural areas with easy access to suitable trees.
I suspect that, as often as not, ordinary people did not use toothbrushes at all, particularly in built-up areas. By the time that I was growing up in the 1940s, toothbrushes were bristle set in a wooden handle.
I understand that slightly better off people cleaned their teeth with a mixture of salt and bicarbonate of soda, which was known as 'tooth powder'. The bicarbonate of soda would have made the salt slightly frothy. Toothpaste was years away.
The treatment for toothache for ordinary people seems to have been to pull out the tooth. My father regularly told the following story, although I am not sure how true it was. He may have been joking. He said that strong thread was tied round the offending tooth with the other end tied round the handle of an open door. Then the door was slammed shut. I suspect this may have happened with children's loose milk teeth in large families where money was scarce. Dentists certainly did exist but were probably used as a last resort.
I shall never forget one day, as a child, when I overheard a local man saying that he cleaned his teeth with Vim. Vim was an abrasive scouring powder used for scouring pans.
I thought I would have a go with it - but I only learnt later that he had false teeth made of metal!
My mouth smarted for days afterwards.
By the 1930s it was not uncommon for people to be so disillusioned with caring for their teeth and with the appearance of their bad teeth that they had them all out in favour of dentures. This of course cost because there was no National Health Service. Some women were actually given this dubious treatment as a 21st birthday present.