Orthodontic tooth removal, known as therapeutic extraction, involves removing healthy permanent teeth to resolve discrepancies between tooth size and jaw size. This long-standing method creates the necessary space for aligning crowded teeth and correcting bite issues. The decision to remove teeth is complex, depending on the severity of the original malocclusion and the desired functional and aesthetic outcome. This necessity is weighed against non-extraction techniques and potential long-term consequences.
Why Tooth Removal Becomes Necessary
The primary justification for tooth removal is severe dental crowding, known as arch length discrepancy. This occurs when the total width of the teeth exceeds the available space in the dental arches, making proper alignment impossible without reducing tooth mass. Orthodontists typically consider extraction when crowding exceeds a threshold, often a discrepancy greater than 10 millimeters.
Extraction is also indicated for correcting pronounced dental protrusion, or bimaxillary protrusion, where the front teeth flare excessively forward. Removing teeth allows the orthodontist to retract these flared teeth into a more upright position, improving the bite and achieving a more balanced facial profile.
The teeth most frequently selected for removal are the first or second premolars (bicuspids), typically four in total. These are strategically chosen because their removal provides a direct pathway for retracting the anterior teeth and resolving posterior crowding.
Alternatives to Creating Space
For mild to moderate crowding, non-extraction methods can create space without sacrificing permanent teeth. One common technique is Interproximal Reduction (IPR), which involves carefully shaving a small amount of enamel from the sides of teeth to reduce their width. This method is suitable for cases with crowding between four and eight millimeters, creating small but cumulative amounts of space.
Expansion methods are often employed for discrepancies involving jaw width to increase the perimeter of the dental arch. Palatal expanders, for instance, widen the upper jaw (maxilla), generating space for crowded teeth.
Orthodontists may also use distalization techniques, pushing back molars further in the arch when space is needed toward the front. These strategies succeed when the jaw structure allows controlled expansion and crowding is not severe.
Evaluating the Functional Benefits of Extraction
When correctly indicated, extractions offer functional advantages that contribute to a stable final result. Removing teeth provides the necessary space to correct severe bite issues, facilitating a stable Class I occlusion—the ideal relationship between the upper and lower teeth. This accurate interdigitation is crucial for efficient chewing and reducing abnormal wear patterns.
The space created enables the precise positioning of the front teeth, establishing a proper overjet and overbite relationship. Ideal alignment ensures teeth are positioned over their supporting bone, leading to increased long-term stability and a reduced risk of relapse. Furthermore, a well-aligned dental arch is easier to clean, lowering the long-term risk for periodontal disease and tooth decay.
Potential Drawbacks and Risks
The decision to extract teeth carries potential drawbacks and risks. A frequently discussed concern is the aesthetic impact on the facial profile. Removing premolars and retracting the front teeth can sometimes result in an overly flattened or “dished-in” facial appearance, especially if treatment is not carefully planned. This retraction can lead to a noticeable reduction in lip prominence, potentially causing a sunken profile.
A significant biological risk is external apical root resorption (EARR), the permanent shortening of tooth roots associated with orthodontic movement. Research suggests EARR may be more prevalent in extraction cases compared to non-extraction treatments, likely due to the greater distance teeth must be moved. The maxillary central incisors are most commonly affected by this irreversible process. Patients also face general surgical risks, including pain, swelling, and the possibility of infection following the extraction.
Long-Term Stability and Results
The long-term value of orthodontic extractions is intrinsically linked to the stability of the final result. When extractions are performed in cases of severe tooth-to-jaw size discrepancy, they allow the remaining teeth to be positioned in harmony with the underlying skeletal structure. This harmonious positioning is widely considered a key factor in achieving a more biologically stable outcome.
Regardless of whether teeth are extracted or not, the permanence of the alignment depends heavily on the consistent use of retainers after the braces are removed. Retention is considered a continuation of the treatment, as teeth will naturally tend to shift back toward their original positions over time. Patients may be given a fixed retainer, which is a thin wire bonded to the back of the front teeth, or a removable retainer, which must be worn according to a prescribed schedule. Properly planned extraction treatment, followed by dedicated retention, provides the most reliable pathway to maintaining the final alignment for many years.