If you’re like most people, you’ve probably never heard of the rare conditions known as tooth fusion or germination, and understandably so. It is estimated that only about 2.5 percent of Caucasian and 5 percent of Asian children experience either of these dental issues, and most people never hear about either condition unless it affects them or their child. So, what are germination and fusion and should you be concerned if your child is affected? Dr. Stephen Hill of Allen, Texas sheds some light on these little know dental phenomena.

Though most are born toothless, the average child eventually grows twenty baby teeth before losing them to make room for their permanent adult teeth.  Sometimes, however, that number is off thanks to rare conditions known as fusion and germination.


Tooth fusion is what happens when two separate tooth buds grow together and form into one tooth that is literally fused together. Fused teeth may have two separate tooth buds, and even their own pulp chambers and canals, but upon extraction or falling out, will still be fused together as one solid tooth. Fused teeth are more common in children than adults, but in extremely rare cases can appear in adult teeth.

On the other hand, tooth gemination is what happens when a single tooth base splits off and forms two teeth that on the surface of the crown appear to be separate – but are actually still conjoined at the base. Much like tooth fusion, tooth gemination is much more common in children than adults, however it is more likely to occur in adults than tooth fusion.

So, what should you do if your child is diagnosed with tooth fusion or gemination? According to Hill, it depends on the tooth.

"Teeth that are fused or geminated should be monitored closely by the parents and dentist," he said. "Often, geminated teeth may be more prone to cavities because the space between the crowns is so tight- it can make brushing and flossing that tooth very difficult." 

Another issue that may occur with fused or geminated teeth is that because of their size and complex root system, the fused or geminated tooth may have trouble falling out on its own, requiring an extraction.  This is especially important because in ideal conditions, two teeth should be growing underneath one fused or geminated tooth. This means that by failing to fall out, the fused or geminated baby tooth can stall the development of not just one, but two adult teeth and cause a lot of crowding on the surface in the meantime.

Other potential problems caused by geminated and fused teeth?

"Sometimes there are no adult teeth below a fused or geminated tooth," Hill said. "This can create a big gap when the fused or geminated tooth falls out- and would most likely require braces to correct." 

Thankfully, Hill says just because a child has a fused or geminated baby tooth does not mean they will have a fused or geminated adult tooth, but in some extremely rare cases, adults do develop teeth with these phenomena. When this occurs, patients can choose to leave the tooth as is, try to have the tooth surgically separated without removing it, or even have it filed down to take up less space, usually requiring a crown and/or root canal as well.

 "The most important thing to remember about fused or geminated teeth is that most of the time they pose no danger to the child, and shouldn’t be cause for much concern," Hill said. "As long as you are paying close attention to brushing and flossing, and you are working with your dentist to keep a close eye on the development of adult teeth below the surface, most fused or geminated teeth won’t require any intervention."