Brushing Teeth on Shabbat: A Reevaluation in Light of Recent Research – Part Two by Rabbi Dr. Ephraim Rudolph DDS


Kol Torah proudly presents this second part of a groundbreaking Halachic piece written by Rabbi Dr. Ephraim Rudolph, a TABC alumus. Last week, we raised the concern that tooth brushing might violate the rabbinic prohibition of Refuah, taking medicine on Shabbat, in light of recent research indicating the therapeutic nature of teeth brushing. This issue will begin by discussing possible reasons to permit brushing teeth on Shabbat for the sake of preventing illness.

Prevention of Future Illness

Despite the recent research indicating the therapeutic benefits of brushing teeth, it is possible to argue that it should not be classified as refuah because remineralization may be considered a dynamic process rather than healing, and the “white spots” that are “cured” by fluoride are not actual cavities that would classify someone as a choleh. Furthermore, some professionals and scientists still question the validity of the idea that the remineralization process can reverse caries. They maintain that the regression of the white lesion may be due to brushing the biofilm off the teeth or that the fluoride in toothpaste cannot positively affect the demineralization-remineralization struggle[1]. Additionally, not all scientists agree that the bactericidal capabilities of fluoride have any direct effect on the reduction of cavities [2]. Also, some studies have shown that only certain toothpastes have the ability to reduce bacteria[3]. Given all of this, it may be possible to argue that toothpaste does not provide refuah.

However, there still may be an issur of fluoride use on Shabbat. This is due to the fact that all agree that fluoride at the very least prevents future decay. Therefore, this becomes an issue of whether or not a healthy person may engage in an act on Shabbat that will fortify his wellbeing and thereby prevent future illness.

The Magen Avraham argues that a healthy person may not take medicine on Shabbat for the purpose of refuah[4], whereas the Beit Yosef writes that it is permissible[5]. R. Ovadia Yosef writes that even the Magen Avraham would permit tooth-brushing because toothpaste is not a medicine; the purpose of tooth-brushing is to remove the food and plaque from the teeth before they cause the teeth to rot. As noted above, R. Yosef classifies this as “mavri’ach ari,” not as refuah.

However, as we further noted, this is not how brushing prevents cavities. Even if we do not consider remineralization to be “healing,” it is indisputable that the prevention capabilities of fluoride go beyond simply the removal of plaque. Since this form of prevention is more than just mavri’ach ari, the Magen Avraham might indeed maintain that it is prohibited on Shabbat.

One might argue that even given its extensive preventative qualities, brushing teeth is similar to taking vitamins, which in general are not taken to cure illnesses, but rather to strengthen healthy individuals[6]. The permissibility of taking vitamins on Shabbat is subject to dispute among the Poskim.

R. Moshe Feinstein explains that the Magen Avraham is referring to people who are healthy but have weak dispositions, and they want to take medicines that will help them fortify their constitutions. In such individuals, the medication leads to some sort of physiological change, and it is therefore prohibited for them to take medication on Shabbat. However, if a healthy person has no health concerns but nevertheless wants to take the medication in order to further strengthen himself, even the Magen Avraham would allow him to do so on Shabbat. R. Feinstein writes that vitamins fall into the latter category. They do not create any real change in the body or alter a person’s overall constitution; they only minutely fortify a person, in the same manner as does eating fruits and vegetables. Therefore, he concludes, it is permitted to take vitamins on Shabbat even according to the Magen Avraham[7].

R. Shlomo Zalman Auerbach, in contrast, is of the opinion that it is forbidden to take vitamins on Shabbat. They are permitted only if they are taken as a food supplement, not in order to strengthen oneself[8]. According to this view, any vitamin, no matter the degree to which it will strengthen a person, is prohibited[9].

Fluoride in toothpaste should at the very least be viewed as akin to a vitamin, and therefore it is subject to this disagreement between R. Feinstein and R. Auerbach. However, one could argue that even according to R. Feinstein, toothpaste is problematic according to the Magen Avraham. In his responsum, R. Feinstein concludes that if a person is truly weak in his nature and the vitamins actually cause the body to become strong, the scenario is subject to the disagreement between the Beit Yosef and the Magen Avraham, and we should be strict in this case because the Pri Migadim and the Levush seem to agree with the Magen Avraham’s view. Since, as explained above, most people’s teeth naturally become weak through demineralization and fluoride “strengthens” the tooth by either reducing and inhibiting demineralization or by enhancing remineralization, perhaps even R. Feinstein would maintain that tooth-brushing is prohibited on Shabbat.

Furthermore, the very comparison to vitamins is questionable. As presented earlier, fluoride and other ingredients act directly on bacteria. This is more than what a vitamin is capable of doing; vitamins enhance and strengthen the body but do not act directly on bacteria.

However, according to those scientists who maintain that the bactericidal effect of fluoride does not play a role in the reduction of cavities, or for those toothpastes that do not have disinfecting abilities, fluoride is indeed comparable to vitamins. It therefore could be argued according to this scientific understanding, and if fluoride is viewed as simply fortifying but not strengthening the teeth, then according to Rav Moshe tooth brushing should be allowed on Shabbat, at the very least if one uses non-bactericidal toothpaste.

With regard to gingivitis, a conscientious brusher would most likely not have the disease. In his case, brushing will solely help prevent future gingivitis. However, the prevention of gingivitis is different from the prevention of cavities. The ingredients in toothpaste prevent gingivitis by killing the bacteria before they can become harmful or by preventing the colonization of the bacteria. Thus, use of toothpaste may be more similar to the case of using a bandage to cover a healed wound, and the Magen Avraham permits this type of prevention[10]. The act of brushing itself also prevents gingivitis, as frequent brushing removes plaque, which is used by the bacteria to cause harm, and also disrupts the biofilm, thereby preventing colonization on the teeth[11]. This would be classified as mavri’ach ari, and not refuah.

In summary, given the recent research, it is difficult to classify fluoride’s anti-cavity prevention powers as purely mavri’ach ari. Furthermore, the prevention that takes place is for someone who is in a weakened state, i.e., the demineralized enamel, in which case even R. Feinstein would be strict. Finally, according to many researchers, toothpaste has antibacterial properties which would remove toothpaste from being classified as a preventative material[12].

Possible Leniencies:

Common Sense Perception

Rav Asher Weiss responded in a teshuva addressed to this author that the prohibition of refuah is based on a common sense perception and not based on science[13]. People brush their teeth in order to maintain a healthy mouth. They do not brush with the perception that they are healing their teeth with toothpaste[14]. Therefore, even if remineralization is refuah, there would still no prohibition of refuah on Shabbat[15].

Sakanat Ever

In a personal conversation, R. Hershel Schachter shlita concurred that it is possible that given the recent research on the therapeutic benefits of fluoride and antimicrobial agents, there is a concern that brushing one’s teeth should be considered a prohibited act of refuah on Shabbat[16]. However, R. Schachter suggested that brushing teeth on Shabbat is still permitted – even for people with cavities and gingivitis – because if the cavity is not treated properly, no matter how small it is at present, the damage may progress and potentially result in tooth loss and diminished function of the jaw[17]. Similarly, gingivitis can progress to periodontitis, a gingival inflammation coupled with bone loss, and severe periodontitis can result in tooth loss[18]. Thus, neglecting to brush one’s teeth on Shabbat raises a concern of sakanat ever, loss of the proper function of a limb[19]. Although not all neglected cavities and gingivitis result in tooth loss, there is at least a doubt of sakanat ever, and we treat a safek sakanat ever as a vadai sakanat ever[20]. Since one is allowed to violate a din derabbanan in order to prevent sakanat ever, R. Schachter maintains that brushing one’s teeth is permitted on Shabbat despite its therapeutic benefits.

R. Shlomo Zalman Auerbach rules that if a person is not currently sick but he will become a choleh she’ein bo sakana if he does not take medicine, he is allowed to take medicine on Shabbat[21]. This is true even if the person will get sick only after Shabbat if he does not take the medication on Shabbat[22]. Similarly, R. Schachter notes, even though cavities and gingivitis will not progress to the point of tooth loss on Shabbat itself, and indeed will take years to reach that level, it should be permitted to brush teeth on Shabbat in order to prevent sakanat ever in the future.

R. Schachter points out that although in theory missing one day of brushing and rinsing will not cause tooth loss, however many people are busy during the week and take care of their teeth properly on the weekend. Therefore, in reality brushing teeth on Shabbat is critical to prevent a person from sakanat ever.[23]         

There is a big difference between Rav Weiss’s leniency and Rav Schachter approach. The foundation of Rav Weiss’s leniency is based on the current perception of brushing teeth. However, due to the push in the dental and oral health care community to educate people about this new understanding of fluoride, it is possible that the perception of brushing teeth will change. While many people may not fully understand remineralization they may still in the future come to perceive fluoride as a vitamin that they are using to re-harden their teeth. If this possibility occurs one may need to rely on Rav Schachter’s leniency.

We will, God willing, continue this piece next week. We will begin the next part of this series with other possible reasons to permit brushing teeth on Shabbat, including the leniency applied to sick people on Shabbat.

[1] L.L. Tathiane, Anelise Fernandes Montagner, Fabio Zovico Maxnuck Soares, and Rachel de Oliveira Rocha, “Are Topical Fluorides Effective for Treating Incipient Carious Lesions? A Systematic Review and Meta-Analysis,” JADA 147:2 (February 2016): 84-91.

[2] Cesar R. Reyes, Raphael Hirata Jr., and Paulo P. Sergio, “Evaluation of Antimicrobial Activity of Fluoride-Releasing Dental Materials Using a New In Vitro Method,” Quintessence International 34(6) (June 2003): 473-7.

[3] V.I. Haraszthy , J.J. Zambon, and P.K. Sreenivasan, “Evaluation of the Antimicrobial Activity of Dentifrices on Human Oral Bacteria,” J Clin Dent. 21(4) (2010): 96-100.

[4] Magen AvrahamOrach Chaim 328:43. The Pri Megadim quotes the Levush, who agrees with this view.

[5] Beit YosefOrach Chaim 328:37. The Bach concurs with this view.

[6] There may be some vitamins that are capable of refuah as defined by Halakha.

[7] Iggerot MosheOrach Chaim 3:54. R. Feinstein claims that the Pri Megadim is also in agreement with his chiddush (novel approach), but he points out that the Machatzit HaShekel is not.

[8] Minchat Shlomo 2:34:37, Shulchan Shlomo 3:328:1; Shemirat Shabbat Kehilchata, ch. 34, note 85.

[9] See Yalkut Yosef 328:55:63, who cites this debate. See Pitchei Teshuvot 328:62 notes 496 and 499.

[10] Magen AvrahamOrach Chaim 328:31.

[11] Richard H. Nagelberg, “Understanding Advances in Oral Rinse Technologies,” Compendium of Continuing Education in Dentistry (October 2011).

[12] The only remote possibility of allowing fluoride on Shabbat even if one compares fluoride to vitamins is if one follows the view of the researchers who don’t believe that toothpaste has significant antimicrobial properties, to reject the notion that demineralization equals a weakened state and to follow Rav Moshe’s leniency.

[13] Rabbi Yitzchok Zilberstien offered a similar oral response to a friend of the author; that people brush with the intention of removing plaque, not to heal teeth. Rav Weiss concurs.

[14] Or that they are even strengthening their teeth with some sort of vitamin.

[15] It is possible that not everyone agrees to this distinction. The Shulchan Shlomo quoted Rav Shlomo Zalman as debating whether or not based on new scientific insight brushing is prohibited due to the issur of refuahand Rav Shlomo Zalman never mentions this leniency.

[16] It is possible that Rav Schachter gave a different leniency because he does not agree with Rav Weiss’s distinction.

[17] O. Fejerskov and E.A.M. Kidd, eds, Dental Caries: The Disease and its Clinical Management (Copenhagen: Blackwell Monksgaard, 2003).

[18] M. Schatzle, H. Loe, W. Burgin, A. Anerud, H. Boysen, and N.P. Lang, “Clinical Course of Chronic Periodontitis: Role of Gingivitis,” J Clin Periodontol 30(10) (2003): 887-901; A. Hugoson, B. Sjodin, and O. Norderyd, “Trends Over 30 Years, 1973-2003, in the Prevalence and Severity of Periodontal Disease,” J Clin Periodontol. 35(5) (2008): 405-14.

[19] See Ketzot HaShulchan 138 : Badei HaShulchan 18

[20] Minchat Shlomo (Tinyana) 60:15.

[21] Ibid. 60:16. The Radbaz writes that refuah is forbidden on Shabbat even if one thinks that he will become sick in the future. R. Auerbach clarifies that this is true only when there is a safek if one will become sick; if he certainly will (vadai), then refuah is permitted. Our case is also only one of safek; if one does not brush his teeth, he may lose his teeth. However, the Pitkei Teshuvot (328, n 24) suggests that the Radbaz is referring only to refuah that violates a melacha. Taking medication is a lesser prohibition, so he might agree that it is permitted even if there is only a safek that one will become ill in the future otherwise. Alternatively, one could argue that the Radbaz was speaking about a choleh she’ein bo sakana, while our case is one of sakanat ever.

[22] Pitchei Teshuvot 328, n. 514                            

[23] After speaking with other Rabbanim about this leniency a few questions were raised. Is it really true that many people only brush properly on the weekends and that if they would forgo brushing on Shabbat they would be in jeopardy of losing their teeth? Also is it true that brushing only on the weekends will prevent tooth loss? As will be presented later in the article, remineralization requires a constant level of fluoride and if remineralization is the key to retaining teeth than brushing teeth only on Shabbat may not be successful in preventing decay and future tooth loss. Additionally, it is interesting to note that the earlier poskim did not utilize this heiter. While they may have not been aware of the remineralization aspect of brushing, they did know that brushing prevents the decay that results in tooth loss. Yet no one applied the leniency of sakanat ever to permit brushing on Shabbat. 

Brushing Teeth on Shabbat: A Reevaluation in Light of Recent Research – Part Three by Rabbi Dr. Ephraim Rudolph DDS

Brushing Teeth on Shabbat: A Reevaluation in Light of Recent Research - Part I by Rabbi Dr. Ephraim Rudolph DDS