A relatively common problem that I see as an orthodontist is a patient who never developed upper lateral incisors. Lateral incisors are the teeth immediately to the right and left of the two front teeth. The first thing that I explain to the patient and their parents is that this is not something that went wrong with the way the child was raised- this did not happen because they didn’t eat enough broccoli, or because there was an accident or lack of fluoride! Technically, the condition is called lateral incisor agenesis, and the failure of these teeth to form is thought to have a strong genetic component, arising from mutations in specific genes that impacts about 2% of the population.
The earlier missing lateral incisors are detected the better, as early detection often keeps more treatment options open. This is one of the reasons the American Association of Orthodontists (AAO) recommends an initial orthodontic examination around the age of 7. At this age, we can clearly detect that lateral incisors are not developing, and start to review options for the family involved. Lateral incisors usually erupt and replace the existing primary (baby) teeth at the age of 7-8 years old. If the laterals are missing, the baby teeth usually will remain and the missing laterals could go undetected by the family unless detected by the dentist or orthodontist. The upper canines, which are the third teeth from the center, will often erupt where the lateral incisors should be, and make the lateral baby teeth fall out. This is the age (usually 10-13 years old) where the problem will become visibly apparent. Young teens have social and aesthetic concerns, as the pointy canines are in a place that they don’t belong, and are often accompanied by excess spacing.
When missing lateral incisors have been identified by your dentist or orthodontist, the decision of how to treat this issue can be quite complicated, and involves many factors including facial and skeletal structure, dental relationships, individual tooth morphology (shape and appearance), aesthetic preferences, the age of the patient and financial considerations. Because I see so many of these patients in my practice, the following is a basic guide to properly treat this condition.
There are two main treatment options for replacing these missing laterals:
1) Opening the space where the laterals should be (and moving the canines back to their proper location if they erupted too far forward) which will set things up for implants and crowns to be placed in the future.
- Advantages of this option are: 1) All the teeth are left in their natural, ideal position in the mouth, with all their individual shapes and contours looking like they “belong” in that position. 2) Once the implants are placed, they are extremely durable and should last a lifetime. 3) Placing an implant leaves the surrounding teeth in their natural healthy state, as opposed to bridges that require greatly reducing the tooth structure of the two usually entirely healthy adjacent teeth (this option has largely fallen out of favor for this reason).
- Relative disadvantages/considerations of the implant option: 1) After the braces are removed, the patient usually has several years of open spaces where the space was left for the future implant (I will explain the reason for this below). 2) Because there are spaces, a removable retainer or “flipper” with plastic teeth will be worn in public so it appears that there are teeth in these areas. Usually these need to be removed while eating. For some patients there are there are “fixed” options that are bonded in place to the adjacent teeth, but they are not as durable as the future permanent tooth replacements. 3) The longer there are missing teeth in an area, the more supporting bone (called the alveolar ridge) disappears. A bone graft is often needed in these areas to make sure that there is a sufficient thickness of bone under the gingiva (gums) to support and completely surround the implant. 4) This is usually a highly visible area, and it may be difficult to make the gingival area look really nice, especially if there has been a fair amount of bone loss in this area. It is truly an art form to get the gum contours to look natural around an implant site! 5) Of course, finances are a consideration, as having bone grafts, implants and crowns done properly will come with their respective fees.
2) The second option for missing lateral incisors in what is called canine substitution. This is where the orthodontist moves the canine into the missing laterals space.
- Advantages of this option are: 1) All the teeth in the mouth are natural, 2) At the end of braces, all the spaces are closed, and there is no time period waiting with open spaces in the mouth, 3) there is no need for large procedures such as implant placement or bone grafts after the braces are removed, and therefore the associated costs are usually less. 4) The finish of the gingival (gum) structure is usually more predictable.
- Relative disadvantages of this option: 1) The upper canines are taller, wider, have a more convex surface, have a pointed tip, and are a darker shade than the lateral incisors. Therefore, these teeth need to be extensively reshaped in order to have the appearance of lateral incisors, and may need additional cosmetic procedures by your dentist to get the color and shape correct (bonding, veneers, or whitening). 2) Every upper tooth other than the two central incisors are technically not in the correct space, they are one full tooth forward of where they should be located. Often they will fit great in this position, sometimes they will not- your orthodontist will have a good idea if your teeth will fit together nicely with this option.
Having said the above, these factors are “all things being equal” comparisons. Facial structures, teeth, and the upper and lower jaws come in all variety of shapes, sizes and relative relationships to one another. These individual factors will also largely influence the decision as to which option to choose. For example:
- If your bite is fitting ideally with little crowding, you have a great profile and lip structure and you are just missing two lateral incisors, you will likely be a great candidate for two implants.
- If the shape of your canines would require too much tooth removal to have an acceptable appearance (or your first premolars are very short and will not look acceptable in the canine position), then you may lean towards the implant option.
- If you have upper teeth that protrude forward of the lowers, or have considerable crowding of your lower teeth, you may be a better candidate for canine substitution.
- If your upper and lower teeth are both tipped outwards too much (called biprotrusion), with or without lower crowding, you may be a candidate for canine substitution, along with extraction of two lower teeth.
- If the upper canines have erupted into the missing incisor spaces, and all the premolars and molars behind the canines have drifted forward a large distance, it may be extremely difficult to move them back to make space for implants, especially as a late teen or older.
These are just a few of the different factors that we consider when helping patients decide what is best for their situation. The take home message is that there are multiple factors that go into deciding the best course of action when dealing with the issue of missing lateral incisors. Your orthodontist and dentist should work together to determine the best plan for your individual teeth, facial structure, and esthetic preferences.
Dr. Dan Rejman is a board certified orthodontist in Castle Rock, Colorado. He maintains two busy practices exclusively in Castle Rock.