Photo Credit: Jewish Press
Rabbi Dr. David Katz

Can kohanim get dental implants that use ground-up bone from a dead body? Can a Jew be tattooed with pink ink after cleft palate surgery to mask the scar that remains on his lip? Is it necessary to kasher dentures before Pesach? These are just come of the questions addressed in a recently published book, Kesser Dovid: The Halachic Guide to Dentistry (Feldheim), by Rabbi Dr. David Katz.

A practicing dentist for more than three decades, Rabbi Katz is head of oral diagnosis at New York Presbyterian Hospital Queens, associate clinical professor of dentistry at Columbia University School of Dental Medicine, and director of halachic dentistry at Touro College of Dental Medicine. A resident of Teaneck, New Jersey, Rabbi Katz is the father of four (including one dentist) and the grandfather of a half dozen.


The Jewish Press: In Kesser Dovid, you write that most poskim allow one to get a dental implant. What would be the reason to prohibit it?

Rabbi Dr. Katz: There are three potential problems: nivul ha’meis (desecration of the dead), halanas ha’meis (delayed burial of body parts) and hanaas ha’meis (benefiting from the dead). All three are major prohibitions that pertain to everybody and even more so to kohanim who are not allowed to become tamei.

Most poskim, however, hold that there is enough of a change that takes place in the bone graft used for dental implants so that it is no longer considered bone. The companies that manufacture the bone graft demineralize the bone and ground it up into an almost powder form. Also, it comes from a bone bank rather than an individual body, which is another reason to allow its use for dental implants.

You discuss many other interesting teeth-related questions in your book. Let’s go through some of them: Mouthwash on a fast day.

The potential violation would be tasting on a fast day, but the Achronim tend to be meikel on fast days other than Yom Kippur or Tisha B’Av. In fact, the Shulchan Aruch specifically says regarding normal fast days that if someone is accustomed to washing his mouth in the morning, he can do so on these days as well. Even on Tisha B’Av, if someone is an istenis – he is fastidious and can’t bear his bad breath – we tend to allow it.

Identifying a dead body based on dental records.

That is one I got involved in personally. The day after 9/11, I was asked to come down to the site of the World Trade Center to help identify bodies. I worked in the morgue trying to collate information from the dental offices of people who were missing, matching them up with the teeth and jaws of the corpses being presented to us. It was a very moving and sobering experience.

But to answer your question, halacha allows identification of a meis based on, for example, the type of filling or crown used for a specific tooth, a specific anatomic anomaly on the bone associated with a particular tooth, etc. According to halacha, identifying features are categorized as either “simanim muvhakin” (unique personal features), “simanim beinonim” (intermediate features) – two of which are the equivalent of a siman muvhak – and simanim geru’im (suggestive features).

Tattooing to mask the scar remaining after cleft palate surgery.

Up until recent times, when a cleft lip was repaired, the person was left with a white scar. It’s only in the last two decades that we started to learn that we can make a cleft lip look more natural and not noticeable if we inject the scar with a red dye that looks exactly like the rest of the lip.

Now, tattooing is normally assur, but most poskim hold there is no biblical prohibition if writing is not involved. There’s still a rabbinic prohibition, but, in short, many poskim believe that the enhanced [self-confidence] a person attains by having a [normal-looking lip] overrides the rabbinic prohibition.

Doing dentistry work on one’s parent.

Generally speaking, you’re not allowed to inflict any sort of wound on a parent. But poskim have ruled that since children treating their parents have no intent to wound them, there’s room to be lenient if the parent prefers being treated by his or her child. This is another situation where many poskim take a person’s psychological welfare into consideration since some parents are more comfortable being treated by their child.

Kashering dentures for Pesach.

There are many different opinions on whether it’s necessary and, if it is, how to do it. There are a few people who require hagalah [boiling], but in my personal opinion, hagalah is not just overkill but can potentially ruin the denture. Many poskim feel the best option is just to abstain from eating chametz 24 hours before the time of biur chametz and put the denture in a denture cleanser.

Others hold, though, that you should do irui and run the denture under hot water very briefly. Still others say you can dip it in a kli sheni filled with hot water for a second since that duplicates the type of exposure the denture has in the mouth, and the rule of thumb is we always kasher things in the same way that they absorb food.

You write in the book that some people believe kashering dentures is unnecessary – that a proper cleaning is sufficient. What’s the reasoning behind this opinion?

It’s based on the shita of the Rambam and brought down by Rav Shlomo Zalman Auerbach, who wrote a brilliant teshuvah regarding crowns and fillings. He held that anything in the mouth more than six hours is pagum – meaning, the taste has been totally destroyed by the saliva and digestive enzymes in the mouth. So there’s nothing to worry about.

You write that becoming a doctor or dentist is halachically problematic for a kohen. As a kohen yourself, how did you handle this question when you were considering going to dental school?

I was peripherally aware of the question, but the teshuvah by Rav Moshe Feinstein that was very strict on this issue was written in the early 1970s and not widely circulated until the late 1970s, early ‘80s. I went to school in the mid-1970s and had gotten a hetter. Poskim since Rav Moshe tend to be machmir, but originally it was not so clear that it was prohibited. In fact, prior to Rav Moshe’s teshuvah there were two Israeli chief rabbis who were meikel.

I want to be very clear, though: Almost everybody holds that even if a kohen can attend medical or dental school, he cannot participate in any way shape or form in the actual dissection of a dead body. He can only stay in the room and observe. There’s only one posek in modern times who allows kohanim to actually participate in the dissection. That’s Rav Goren, and he set forth very specific guidelines on how to do so.

You write that it is much easier for a kohen to attend dental school than medical school since dissection is far less critical to the education of dentistry students.

That’s correct. But it’s very important that he make arrangements in advance. To go in without properly notifying the school and then for the school to find out you’re not participating creates a potential chillul Hashem. Guidelines need to be set forth beforehand in an honest and kavodik manner so that people will respect us and not think we are trying to run circles around them.

You said earlier that you helped identify bodies post-9/11. How were you able to do so as a kohen?

I asked several poskim, all of whom said that in a meis mitzvah situation – where no one knows the identity of a body – an expert is allowed to become tamei to help identify it.

In your 35 years of practicing dentistry, what would you say were the most interesting halachic questions you encountered?

One was about five or six years ago when two rabbis in Bnei Brak ruled that people who had fillings or crowns in their mouth could not eat chametz within 24 hours of Pesach and were not allowed to eat any sharp foods – for example, onions, garlic, or radish – on Pesach based on the halachic rule of “mecha’ye l’shevach” (rejuvenating tastes).

The question was presented to me, and since I didn’t want to give my own personal psak, I went to rabbis more learned than myself who ruled, based on Rav Shlomo Zalman Auerbach’s teshuvah, that everything in the mouth is pagum after six hours – even chametz. In other words, the Bnei Brak [ruling] is a chumra and a person with fillings or crowns doesn’t need to be concerned.

What would you say to someone who argued that all the intricate back-and-forth halachic debates in your book are superfluous since in the end halacha will almost always accommodate useful innovations such as dental implants, for example?

You’re assuming that everybody is coming from the same background as yourself, which is not the case. For example, in Bnei Brak it is the accepted opinion that people with fillings may not eat sharp foods on Pesach. They also maintain that one may not chew sharp maror. It must be swallowed. The poskim who issued these rulings are not lightweights. They are great gedolim.

I’ll give you another situation. A number of years ago, there were people advocating that a married woman not be allowed to have braces because of mikveh issues. And if they do have braces, they must take them off before tevilah, they said. So in Israel, for example, there were dental offices set up to take braces on and off people who had to go to the mikveh.

Another example is the issue of Listerine breath strips on Yom Kippur. Some say it’s outright asur while others permit them for someone who is very sensitive. So these issues are far from straightforward, and what seems reasonable to you may not be to someone else.

I would say that more times than not, rabbis want to make living life as easy as possible. But even then, they cannot do at the expense of violating biblical prohibitions. For example, you can’t give a tissue graft in a non-pikuach nefesh situation. Even if you want to, you can’t. The same with being treated on Shabbos. If it’s not pikuach nefesh – and there’s a debate on what is and what isn’t pikuach nefesh – it’s prohibited.

You got semicha a decade ago, which is about 40 years later than most people get it. What made you pursue semicha as a middle-aged man?

I come from a line of rabbis and I didn’t want to be the one to break the chain. I had always been learning and I’m currently on my third Daf Yomi cycle, but I had started to feel a calling to learn in a more structured method and achieve semicha. So I decided back in 2006 to find a program that would accommodate my schedule. Ultimately I joined one run by Yeshiva Keter HaTorah, which required approximately 20 hours of learning a week for two years.

My chavrusa was the rosh yeshiva of the program, Rav Doniel Channen, so I was very fortunate. I would get up at 3:30 in the morning and learn with him three or four times a week. For the final bechina, which was a 10-12 hour test followed by a 3-4 hour oral farher, I had to travel to Israel. It was no simple situation.


Previous articleThirteen Outrages In The Rubashkin Prosecution
Next articleQuick Takes
Elliot Resnick is chief editor of The Jewish Press and the author and editor of several books including, most recently, “Movers & Shakers, Vol. 2.” Follow him on Facebook.