I have read your article on tori, which said they appear on the roof of the mouth and are more common in women than men. I have a seven-year-old son who has two lumps under his tongue along the inside of his teeth. His dentist said they may be tori. He seemed alarmed that they have already begun at such a young age, but he assured me that lots of people have them and they are harmless. I would like to learn as much about this as I can. Any help you can give would be appreciated.

M.C.

Torus mandibularis (plural, tori) is a benign, bony outgrowth from the inner surface of the lower jaw (mandible). Another commonly used medical term you may hear is exostosis (the plural is exostoses). Exostosis translates as "bony outgrowth" -- no mystery there.

Tori are far more common in older individuals than in children. Now, tori have a characteristic "look and feel," so if your dentist thinks these are tori, chances are very good that he's right. However, it concerns me that he said "they may be tori," a hedging reply that could indicate some uncertainty on his part. I think that it would be fair to ask him, "If they aren't tori, what else could they be?" Since tori are uncommon in kids, this is a reasonable question.

There are, unfortunately, a wide variety of "hard growths" that can arise from the mandible. Some of these growths arise from the mandible itself, while many others arise from the tooth or the tooth root. I am using "growth" in a very loose way to indicate "a lump that does not belong." In some cases, such a growth might represent abnormal development of the underlying tissue (bone, tooth root or tooth); this would include bony growths such as tori and many bony cysts. In other cases, a growth may represent a true neoplasm, or tumor. In the latter group, some tumors are malignant (cancerous), while others are benign (noncancerous). Some growths grow slowly (such as tori), while other growths behave in a much more aggressive fashion.

Thus, your most important task is to confirm that these lumps are tori. It should be possible to confirm this with dental films, but in ambiguous situations other studies may be necessary (such as a "mandible series," a Panorex, or a CT of the mandible). Once the dentist has confirmed the diagnosis, you should question him about the growth characteristics of tori in children. I looked for this information in the medical literature but could not find anything relevant; however, this information might be well known among dentists. If your dentist cannot give you some idea as to what the future holds, he could try asking an academic pediatric dentist. What could be a mystery to one practitioner may be common knowledge to the "super-specialist."

If these growths are indeed tori, then I suspect the answer will be, "Slow growth is common; we'll just have to wait and see whether these tori cause your son any problems." Bear in mind that I am not a dentist (I'm an ear, nose and throat specialist), so please don't take this as the last word!