I am a 25-year-old religious man, and I have a problem that began a few years ago. My skin breaks into a rash after wearing my tefillin on my left arm every weekday. Allergies to pollen run in my family, but nobody has had such a problem. Is there such a thing as being allergic to tefillin? T.N., Elad Judy Siegel-Itzkovich comments: I have been holding on to this query for several weeks, as I did not find an expert who could answer the question. Fortunately, while reading the latest issues of the Hebrew-language Israel Journal of Family Practice and the Israel Journal of Dermatologic Surgery and Dermatology (both published by Medical Media in Netanya, I found identical articles by Dr. Ehud Werner, an independent physician with Maccabi Health Services and Kupat Holim Meuhedet in Kiryat Ono who deals with this exact problem. He says that "tefillin allergy" is relatively rare in Israel. It is due not to the tefillin themselves that contain parchment, but to the potassium dichromate used to process the leather straps. There have been no reported reactions to the formaldehyde or black dye (PPD) used to make the tefillin. "From our experience, the allergy first appears from the age of 13 [bar mitzva] when a boy starts praying with tefillin but can [suddenly] appear even in elderly men." In most cases, continues Werner, the inflammatory response appears in the area of the middle finger, around which the straps are wrapped. It is less common on the forearm and much less common on the nape of the neck. In some patients, the rash appears in the form of "straps," but in others, the rash is not under the places on the skin that are in contact with the straps. In most of the cases, several years pass until the diagnosis is made, but in some, the diagnosis has been made even 10 years or more after the man began to see the rash. Werner estimated that about 24 percent of Israelis put on their tefillin on a regular basis (the vast majority are men, but some women do it as well). Among them, apparently only a handful become allergic to the chemical on them. It may be this is due to the fact that they are worn for less than an hour and usually about 15 minutes, he adds. They are also used only in the early morning when it is cooler and the wearer is not likely to sweat; perspiration could magnify the risk of an allergic reaction. There is a solution permitted by Halacha, says Werner, to place cloth between the skin and the straps but not between the skin and the tefillin boxes worn on the forearm and the head. Most people with this allergy prefer to buy phylacteries whose leather is processed without potassium dichromate. There is a place in Bnei Brak called Machon Pe'er that sells such tefillin. I have two dental implants in my jaw, and they seem to be doing fine. My dentist always tries to save a diseased tooth with a root-canal procedure, while my implantologist claims that implants are the best. I can understand their motivations, but who is right? M.T., Jerusalem Judy Siegel-Itzkovich comments: A recent study in the Journal of Oral Implantology took the second view, claiming that single-tooth dental implants are "98.5 percent successful after seven years," while the American Academy of General Dentistry maintained that "first-time root canals fail 5% of the time and at much higher rates in repeat procedures." I asked Dr. Shlomo Zusman, head of dental services at the Health Ministry, who commented that "a natural organ is always better then a metal replacement" and that a dentist should make every effort to save a natural tooth if possible before recommending a permanent artificial implant. Dr. Steve Sattler, a veteran Jerusalem dentist, commented: What is the better treatment - root canal or implant? As of now, there is no definitive answer. Some teeth have only a root-canal option, others only an implant option and some both." The dentist, using his skill and knowledge, will help the patient decide. The success rate for implants is still only around 80% (any dentist who says it reaches 95% and over is not telling the truth). Some root-canal treatments last for 50 years and more, and some fail after five years. Some implants hold for 20 years, and some fail after a year or two. Obviously, some dentists who are implantology fans will say that implants are the best, and the endodontists will say the opposite. At present, most objective dentists have adopted implantology as yet another option to be used as necessary. Readers welcomes queries from readers about medical problems. Experts will answer those we find most interesting. Write Rx for Readers, The Jerusalem Post, POB 81, Jerusalem 91000, fax your question to Judy Siegel-Itzkovich at (02) 538-9527, or e-mail it to email@example.com, giving your initials, age and residence.