Toothbrushing on Shabbat
Toothbrushing on Shabbat
I am a dentist and I was learning the the halachos of brushing on Shabbat. In Rav Ovadia Yosef’s Tshuva he quotes Rav Zweig who said toothbrushing was assur due to refuah. Rav Yosef disagreed because he said that brushing only removes the food stuff from the teeth so it is only mavriach ari, no refuah is happening. However, this is not so true based on the current research. The science of cavity prevention is no longer about removal of plaque by brushing but all about something called remineralization. In short bacteria eat sugars and produce acid that demineralize the teeth (“softens the tooth structure) after a certain point enough mineral structure has “corroded” away that the bacteria can penetrate into the tooth. REmineralization is the concept that during that demineralized state of the tooth, fluoride and other vitamins and minerals like calcium and phosphate can be absorbed by the tooth and re-harden or remineralize the tooth preventing or delaying the bacteria from entering the tooth. The area that is remineralized in some cases is harder than the original tooth. Fluoride is very potent in the remineralization process and has numerous functions in the remineralization process. Many scientific articles have been written proving and documenting this phenomenon. There is still a debate whether in practical terms it reduces cavities but that is due to the many factors that go into cavity development (diet, genetics how well a person brushes), but it is true that fluoride remineralizes the teeth. The dental world has pretty much accepted this notion and has been working on finding the best combination of chemicals and vitamins that remineralize the teeth the best. Toothpaste companies have added certain ingredients that will enhance the remineralization process. My first question is based on this science would remineralization be called refuah? If it is would it still be allowed on Shabbat? I understand the heiter of ma’chal beri’im but many people have cavities; in certain communities and countries most people have cavities and so brushing for them would be refuah. Also if the dental community believes this is how fluoride works would fluoride would be considered “ikar l’refuah” which maybe would make it similar to aspirin and therefore according to some not be considered ma’achal beri’im? I understand that most people are still under the impression that brushing is to remove plaque but many dental schools are teaching remineralization and many newer dentists are teaching their patients about it. Dentists even prescribe extra strength fluoride for people that have a lot of demineralization also toothpaste companies are marketing this concept as well. So it could be that soon the general population will understand that when they brush they are doing so to help remineralize and “heal” their teeth and that will be their kavana when they brush their teeth. I teach this concept on a daily basis. Finally, even if remineralization is not refuah, and it is considered only prevention, based on our knowledge would fluoride be at least considered a vitamin and therefore subject to the debate about whether vitamins are allowed on Shabbat?
Even if the purpose of toothbrushing would be widely understood as not only removing plaque but rather as actually proactively healing the teeth, this would not be included in the prohibition of Refuah on Shabbos. In order for something to qualify as Refuah on Shabbos it has to be for the purpose of healing an illness. The rationale the Gemara explains is that a person who begins to treat an illness and does not have sufficient medicine may come to violate Shabbos to produce medicine. Any activity done by normal healthy people on a daily basis would not be considered an illness being treated, as there is no concern that one will get carried away for such an activity. He is presently not suffering any symptoms and has no immediate gain from the treatment. The Gemara and Shulchan Aruch discuss various cases which may have positive medicinal value, such as moisturising the skin, and yet for the reason explained above is not refuah.
It should be noted however, that according to most authorities, toothbrushing on Shabbos is prohibited for a different reason. That is, smoothing out the toothpaste is a violation of the Melacha of Memachek. Liquid based toothpaste formula is available for Shabbos use. Some authorities require using a seperate Shabbos toothbrush with thicker bristles to avoid the issue of Sechita, and because of concerns of Uvdin D’chol.
See Igros Moshe O:C 1:112, Tzitz Eliezer 7:30:8, Minchas Yitzchak 3:50.