— Extraction treatment, orthodontics during growth, and care after treatment
When considering Invisalign, it is important to look beyond the clear appearance of the aligners and ask whether the treatment is suitable for your teeth and jaws. Even with the same Invisalign system, the approach and course of treatment can vary depending on the tooth movements required, whether you are still growing, and the condition of your gums and roots.
If extractions are needed, we must plan how the spaces will be closed. For growing children, we also need to consider the permanent teeth yet to erupt and the growth of the jaws. After treatment, maintaining the result is equally important. In this article, we will look at how Invisalign is used and managed under these different circumstances.
We build on Invisalign's advantages and add other treatment when needed
Invisalign offers several advantages: it is less noticeable, can be removed for meals and brushing, and makes treatment schedules easier to coordinate for patients living far from the clinic. Patients who can wear their aligners consistently can benefit from these conveniences throughout treatment.
During treatment, however, some teeth may be difficult to move as intended with Invisalign alone. In these situations, we may consider using brackets and wires in selected areas or switching to fixed appliances at a particular stage. If a patient cannot maintain sufficient daily wear, the treatment approach also needs to be reassessed.
No appliance is perfect for every situation. The goal is to make full use of Invisalign's advantages while drawing on other appliances when needed to achieve a well-finished bite.
Extraction treatment needs more detailed planning, and timing matters
Extraction treatment remains a demanding application of Invisalign. Closing extraction spaces requires control of the inclination and roots of the front teeth while maintaining the position of the molars and the bite. A 2025 systematic review and meta-analysis by Alhafi and colleagues compared 15 studies involving a total of 1,084 patients. In non-extraction treatment, there were no significant differences in treatment quality or duration between clear aligners and fixed appliances, whereas fixed appliances achieved higher treatment quality in extraction cases. 1 However, the participants and treatment methods differed across studies, so these findings cannot be applied directly to every patient.
This does not mean that Invisalign is unsuitable whenever extractions are needed. Depending on the direction and amount of movement required, it can be used advantageously in cases such as protrusion accompanied by crowding or an open bite. We consider how much space will be used to align crowded teeth, how far the front teeth need to move back, and how to control the vertical bite relationship. Some movements are difficult even with brackets and wires, making case-specific planning and the use of auxiliary appliances important.
We also consider the timing of treatment. During growth, remaining jaw growth and dental development can be used as part of treatment, allowing some problems to be approached more favorably than in adulthood.
In adults, growth has finished, and tooth movement must take account of the limits of the supporting bone and the condition of the periodontal tissues. If closing extraction spaces and controlling the roots of the front teeth are judged difficult with Invisalign, extraction treatment with brackets and wires may be chosen. Conversely, non-extraction treatment can be considered if sufficient space and the desired improvement in protrusion can be achieved without extractions.
This is why identifying problems early and not missing the opportunity to use growth and development are important. It does not mean that every child needs to start wearing an appliance early. The role of early diagnosis is to distinguish problems that need intervention now from those that should be monitored as the child grows.
Invisalign First requires planning for later permanent-tooth treatment
Invisalign First can be used for children in the mixed dentition, when primary and permanent teeth are present together. Many children receive this treatment, which focuses on aligning the front teeth, creating space for permanent teeth to erupt, and improving the bite in step with growth. For Class III malocclusion with a narrow upper dental arch, we plan arch expansion; for Class II malocclusion in which growth can be used, treatment is tailored to the child's condition. Other growth-modification appliances may also be used, depending on the skeletal problem.
One point I always explain to parents is that completing Invisalign First does not mean that all permanent-tooth orthodontic treatment is finished. Treatment at this stage is an early phase that creates space and a favorable eruption environment for the front teeth and other permanent teeth yet to come through. It does not complete the alignment and final bite of permanent teeth that have not yet erupted.
After Invisalign First, we therefore continue to monitor the eruption of permanent teeth and jaw growth. Depending on the later alignment and bite, a second phase of orthodontic treatment in adolescence may be needed to complete the permanent dentition. This should be distinguished from retreatment because the initial treatment was incorrect or because of a simple relapse.
Retention also differs from care after adult orthodontic treatment. Because teeth are still being replaced and the jaws are growing, fixed retainers may be used only in selected areas, or removable or modified appliances may be used for a period of time. It is important to adjust the appliances to the child's developmental stage and review them regularly, preserving the space and alignment achieved without obstructing the eruption of permanent teeth.
Keeping teeth aligned over time is also part of treatment
At the end of treatment, I always emphasize wearing retainers. Teeth do not automatically remain in their new positions simply because they are straight and fit together well. Whether treatment used Invisalign or braces, retention is necessary to preserve the result over time.
Retainers include removable appliances, such as Vivera, the clear retainers made by the manufacturer of Invisalign, and fixed retainers bonded to the inner surfaces of the teeth. Appropriate retainers may be selected or combined according to the alignment before treatment and the condition afterward, so they should be used as prescribed by your orthodontic specialist.
Removable retainers should be worn for the time and in the manner instructed, and fixed retainers should be checked regularly for detachment or distortion. If a retainer no longer fits well or the teeth seem to have moved, it is advisable to have them checked rather than waiting until the next routine visit.
Invisalign is about more than transparency. Detailed planning by a specialist, consistent aligner wear by the patient, and retention after treatment all need to work together. Understanding and preparing for this process before choosing an appliance is the first step toward achieving a satisfying result and maintaining it over time.
References
[1] Alhafi ZM, Hajeer MY, Alam MK, Jaber ST. Quality and stability of orthodontic treatment outcomes with clear aligners versus fixed appliances: a systematic review and meta-analysis. European Journal of Orthodontics. 2025;47(6). View paper