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Dentistry/loss of bottom first molars - space maintainers needed?


QUESTION: Hi Dr. Moss,

My son who is almost 7 has developed a sinus tract (no pain, no swelling) on his bottom right first molar. His x-rays show a dark shadow under the this tooth and also his bottom left first molar. The bottom left molar is asymptomatic. Both of these molars had large fillings done about a year ago.

His dentist is recommending extraction of both bottom first molars and space maintainers (lingual arch). What is your opinion? I feel comfortable extracting the one with the sinus tract but not sure about the left molar. I would leave it alone if it can buy us some time.

Your past answers seem to indicate that space maintainers are not necessary for the bottom first molars. Could you please point me to a journal article so that I can make my case with the dentist?

Also, is the space maintainer also unnecessary when the top first molar is extracted. My son's upper right first molar was extracted 6 months ago. It looks to me like the tooth has moved about 1mm.

Thank you very much,
Brent Ridley

ANSWER: Dear Mr. Ridley,

The radiographs of your son's lower first molar teeth clearly indicate that they are infected.
They should both be removed in the near future to protect the the teeth that are developing below them and to prevent the infection from spreading (it will one day.)

There is no need to maintain the spaces for first primary molars, the spaces do not close. Note that there has been no closure in the upper jaw where the first molar is missing.

Your pediatric dentist was trained to make space maintainers for missing primary molar teeth, he or she sincerely believes they are necessary ,trying to re-educate your dentist will not help.

You are caught between two different opinions,and regretfully there is no way that I can help you  other than to tell you that if a space maintainer is placed it will do little harm .

It is not your job to educate your dentist ,you could ask the dentist if or how often s/he has ever seen the space for a first molar close ?  

The reference that you need is not a paper rather it is the text book on orthodontics written by Samuel Hemley (New York University) and my over 45 years of practice and teaching in both Pediatric and Orthodontic dentistry.

Perhaps this helps,

All the best,
Dr. Moss

---------- FOLLOW-UP ----------

QUESTION: Thank you very much for your advice. I am grateful for your expertise.

A few remaining questions:

Should my son take amoxicillin before the teeth are extracted? Does it offer more protection against complications after the extractions?

Would you recommend sealants for his lower permanent molars (both erupted)?

Do you have any advice re: reducing harmful bacteria in his mouth? I have cut out sweets/carbs and I'm brushing and flossing him after each meal.

Thank you,

Dear Mr.Ridley,
Antibiotics are definitely not indicated.
If applied well sealants are effective in preventing cavities in susceptible tooth areas.
I do not think your son is susceptible to cavities, the bilateral nature of his tooth breakdown in his primary molar teeth indicate to me  a developmental problem that occurred for a relatively short period of time when the distal surfaces of  his primary molars were forming.
I suspect something like a high fever caused by illness somewhere between birth and one year of age.
Brushing twice a day with a good fluoride toothpaste is all you need to do to maintain the remaining teeth which appear to be in excellent condition .  Flossing and brushing after every meal or even once a day is neither effective or necessary .
Regarding diet, the best advice is cut down on frequency of snacking between meals. It doesn't make any difference whether it is bread or a candy bar, both have an almost equal potential to feed oral bacteria.  There is nothing in the radiographs or history to suggest that your son has a greater susceptibility to caries.
All the best,
Dr. Moss


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Stephen J. Moss


I am a professor emeritus at New York University, with a background that includes extensive research, scientific writing and biology. I also am an international consultant in health education, particularly in developing education on new science for health professionals and consumers. I am a past president of the American Academy of Pediatric Dentistry, former head of the NYU Division of Oral Biology and I represent the World Dental Federation at the United Nations. I travel around the world to provide health education to professionals and consumers.


Having retired from New York Universit, where I directed the pediatric dentistry training program, a walk-in dental clinic and research on oral biology, I formalized my professional and consumer health education initiative in the form of Health Education Enterprises. This entity consults and provides information on new science pertaining to oral and general health, particularly leading edge concepts that can be employed in the health professions to improve the public's health. As such, I am an expert in communicating new science and its usefulness to professional and lay audiences alike. I also had a pediatric dentistry practice in New York City for nearly 30 years.

I am affiliated with the American Dental Association, the World Dental Federation, the International Association of Pediatric Dentistry and the American Association of Pediatric Dentistry among other formal organizations. My experience has included a research fellowship at the National Institutes of Health and work at the Forsythe Dental Research Center

lpha Omegan USA, Nowa Stomatologia Poland, Journal of Public Health Dentistry, The Journal of the Southeastern Society of Pediatric Dentistry USA, News Bulletin Japan, Journal of Marmara University Dental Faculty Turkey, Italian Journal of Paediatric Dentistry Italy, Asian Dentist Singapore, The Journal of the Israel Dental Association Israel, ROBRAC Brazil, Italian Journal of Paediatric Dentistry
Italy, FDI World, STOMA Portugal, Pediatric Dentistry The Philippines, Modern Stomatology Bulgaria, Journal of the Indian Society of Pedodontics and Preventive Dentistry India

I obtained a doctor of dental science (DDS) degree, a master of science degree and am a board certified pediatric dentist.

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