While dentists must often help children and adults deal with common problems like gum disease and tooth decay, some conditions are rather more unusual. Most children have 20 primary teeth, which give way to 32 adult teeth, but some people can experience developmental disorders called gemination and fusion that disrupt the number of visible teeth. Read this article to learn more about the symptoms of these conditions and find out what a dentist needs to do if he or she diagnoses one of these problems.
What is the difference between gemination and fusion?
People sometimes confuse gemination with fusion because the two disorders result in similar symptoms. In fact, the two conditions are almost entire opposites.
Gemination occurs when a developing tooth tries to split into two distinct teeth. Geminated teeth have one root, but the bud divides into two teeth. As such, when you look on a radiograph, a geminated tooth has one pulp canal and two pulp chambers. While a geminated tooth actually only has one crown, a cleft in the surface can make it look like you have two teeth.
Fusion occurs when two developing teeth fuse together to form one tooth. In these cases, you will have one large crown made from two teeth, but you will still have two separate pulp canals and two independent root chambers.
With gemination, your tooth count is the same as anyone else. With fused teeth, you will have one tooth less than a normal person.
Which teeth are at risk?
Children are at higher risk of gemination and fusion than adults, and these problems most commonly affect primary teeth. These conditions affect up to 2.5 percent of Caucasian children, but Asian children are more likely to experience these problems. Dentists see these symptoms in around 1 in 250 adults. Dentists normally see gemination on the upper teeth and fusion on the lower teeth.
What are the risks and consequences of gemination and fusion?
While gemination and fusion normally only affect your primary teeth, these conditions can disrupt or slow down the eruption of adult teeth. In some cases, geminated or fused teeth will cause crowding, and your child could also end up with large gaps between his or her adult teeth. Sometimes, geminated and fused teeth completely stop the adult teeth erupting.
If fused or geminated teeth are quite narrow, the risk of tooth decay increases because the enamel layer is not thick enough to protect the dentin underneath. Many geminated or fused teeth have deep grooves down the middle, where debris can allow harmful bacteria to thrive. In a few rare cases, permanent teeth never develop under fused teeth.
How would a dentist treat these problems?
A dentist will need to carefully examine geminated or fused teeth to decide how best to treat the problem.
In some cases, geminated or fused teeth will simply resolve themselves. If the dentist can see the healthy development of secondary teeth, he or she will probably leave the teeth alone. Nonetheless, more commonly, a dentist will extract a fused or geminated tooth.
Other options are available for affected adult or secondary teeth. To improve the esthetics, a dentist will sometimes shave down and smooth the surface of an affected tooth. That aside, if the pulp is too close to the surface of the tooth, your dentist will probably recommend a root canal treatment and a crown.
Dentists can sometimes surgically divide fused teeth. This procedure can work well because you still have two pulp chambers and two separate root systems. Nonetheless, this type of work can become complicated and costly because the patient normally needs two root canal treatments. In adult teeth, many people simply leave geminated or fused teeth alone.
Fusion and gemination are relatively unusual problems that can affect tooth development. If you think you or a loved has one of these conditions, talk to your family dentist for more advice.