Extraction of One Lower Incisor for Orthodontic Treatment

GearsEvery now and then I’ll get a question from a reader whose doctor has recommended the removal of a single lower incisor to fix their crowding. Why would anyone remove just one lower incisor? Is this an accepted treatment technique? What are the pros and the cons? In some patients it seems that the only crooked teeth are those right down in front. It is tempting to ask, “Why don’t you just pull out one of the overlapping ones? Although the technique is not new, the removal of a single lower incisor has recently experienced a resurgence with the increased popularity of “short-term orthodontics.” In some cases this is an acceptable option, but there are consequences that must be considered beforehand.

In a normal bite, the number of top teeth and the number of bottom teeth match each other. They fit like gears in a watch and removing a single “gear” in either arch can create problems. If the teeth are of an appropriate size and shape, removing just one lower incisor will create either excessive overbite or a deep bite. Excessive overbite (officially called “overjet”) means that the upper teeth stick out too far relative to the bottom teeth. A deep bite (ironically termed “overbite” by professionals) means that the top teeth overlap the bottom ones too much so that less of the lower teeth are visible. In a patient who wants faster treatment and is willing to accept these compromises, the removal of a single lower incisor may be an acceptable treatment option.

If the lower teeth are too wide compared to the upper teeth, or if the upper front teeth (most commonly the lateral incisors) are genetically too narrow, there is a natural mismatch in the size of the “gears” and the removal of a single lower incisor may actually be the best treatment option. In cases where the upper teeth look great but the lower anteriors are crowded and crooked, an orthodontist may deliberately create a tooth-size mismatch by narrowing the size of the upper front teeth. Using a technique called Interproximal Reduction (IPR), the orthodontist can make the width of the upper front teeth slightly narrower to compensate for the tooth that has been removed in the lower arch.

In both scenarios I just described, there is one compromise that must be acceptable to both the patient and the orthodontist. Removing a single lower incisor always means that the centerline of the upper teeth will line up with the middle of a tooth in the lower arch. This is not usually noticeable to casual observers, but is a tradeoff that should be understood at the beginning of treatment.

In my practice I never remove a lower incisor without doing a treatment simulation first. This can be done “old school” by rearranging the teeth on a plaster model to simulate the final outcome or it can be done digitally using software like Suresmile. Digitally manipulating the teeth before treatment begins helps me determine if I can merely align the teeth in their original size and shape, if I will need to slenderize them (IPR), or if the removal a single incisor is the best option. Even after more than 20 years’ experience, I am still sometimes surprised with the outcome of these simulations.

I have nothing against the removal of a single lower incisor as part of orthodontic treatment in appropriate cases. As I’ve outlined here, patients whose doctors recommend this as part of their treatment should ask about excessive overbite and overjet at the end of treatment. As with many other treatment techniques, there are tradeoffs and you just need to make sure you understand them going in.

NOTE: The author, Dr. Greg Jorgensen, is a board-certified orthodontist who is in the private practice of orthodontics in Rio Rancho, New Mexico (a suburb on the westside of Albuquerque). He was trained at BYU, Washington University in St. Louis, and the University of Iowa in the United States. Dr. Jorgensen’s 25 years of specialty practice and 10,000 finished cases qualify him an expert in two-phase treatment, extraction and non-extraction therapy, functional orthodontics, clear aligners (Invisalign), and multiple bracket systems (including conventional braces, Damon and other self-ligating brackets, Suresmile, and lingual braces). This blog for informational purposes only and is designed to help consumers understand currently accepted orthodontic concepts. It is not a venue for debating alternative treatment theories. Dr. Jorgensen is licensed to diagnose and treat patients only in the state of New Mexico. He cannot diagnose cases described in comments nor can he select treatment plans for readers. Because he has over 25,000 readers each month, it is impossible for him respond to all questions. Please read all of the comments associated with each article as most of the questions he receives each week have been asked and answered previously. The opinions expressed here are protected by copyright laws and can only be used with written permission from the author.