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| Title |
Clear Aligner Therapy Allows Predictable Maxillary Molar Distalization in Non-Extraction Orthodontic Treatment |
| Clinical Question |
In orthodontic patients requiring maxillary molar distalization, does clear aligner therapy compared with conventional orthodontic mechanics provide predictable distalization with effective anchorage and movement control? |
| Clinical Bottom Line |
Current evidence suggests that clear aligner therapy can predictably accomplish an estimated 2-3 mm of maxillary molar distalization while also maintaining acceptable anchorage and movement control. While distal molar tipping and anterior anchorage loss is a possibility with treatment, clear aligner therapy shows promising clinically effective outcomes that are comparable to conventional orthodontic mechanics. Additional randomized control trials can assist in strengthening the certainty of the conclusions. |
| Best Evidence |
(you may view more info by clicking on the PubMed ID link) |
| PubMed ID |
Author / Year |
Patient Group |
Study type
(level of evidence) |
| #1) 38921511 | Shen/2024 | 257 orthodontic patients from 13 included studies (221 patients in 11 studies with relevant data) | Systematic Review and Meta-Analysis | | Key results | This systematic review analyzed 13 longitudinal studies to examine current evidence on the amount of molar distalization that is possible with the sequential distalization protocol of clear aligner therapy. An additional aim of the review was to determine the accompanying effects of rotation and tipping of molars and anchorage loss. The study used meta-analyses on maxillary first and second molars in both post-distalization models and radiographic images. With the addition of a random effects model for the remaining tested parameters, the authors were able to arrive at conclusions while also accounting for variability in study designs of the 13 studies. The meta-analysis demonstrated a significant maxillary first molar distalization of 2.07 mm (95% CI: 1.38–2.77 mm) and maxillary second molar distalization of 2.38 mm (95% CI: 1.19–3.57 mm). An analysis of the parameters using radiographic analysis showed that distalization was achieved at the crown level while root-level distalization was less consistent. Overall, the evidence from each of the studies determined about 2 mm of distalization is possible with clear aligner therapy, although the movement can often be accompanied by side effects of molar crown distal tipping and intra-arch anterior anchorage loss. | | #2) 41015416 | Disthaporn/2025 | 452 orthodontic patients from 16 included studies | Systematic Review | | Key results | The systematic review evaluated 16 studies with a total of 452 orthodontic patients. The aim of the study was to evaluate both effectivity and accuracy of clear aligners in accomplishing maxillary molar distalization and rotation in adult class II non-extraction cases. The studies were categorized into two groups, with Group B (aligner outcomes with refinements) reporting a greater sense of accuracy and distalization due to sequential distalization protocols with refinements. The studies reported that molar distalization ranged between 1.84 mm to 2.98 mm, with some studies demonstrating distalization accuracy close to 85%. Analyses also show that first molar rotation reached 8.09 degrees with a 78.4% maximum accuracy. The study stated challenges with the distalization being anterior anchorage loss, buccolingual tipping, and patient compliance monitoring. Overall, the outcomes analyzed by the study determine that clear aligner therapy can effectively achieve molar distalization and rotation in class II non-extraction cases. | | #3) 38733349 | Wang/2024 | 46 adult orthodontic patients treated | Retrospective Study | | Key results | This retrospective cohort study aimed to evaluate both dental and skeletal changes that come from molar distalization with clear aligners and the total arch distalization that occurs with fixed appliances using miniscrews in patients with mild-moderate crowding. The study evaluated dental and skeletal changes using pre-treatment and post-treatment lateral cephalograms. Both treatment modalities accomplished an estimated 2-3 mm of molar distalization. The clear aligner group demonstrated less distal molar tipping in comparison to the fixed appliance group, with tipping degrees of -2.29 and -5.24 respectively. Additionally, fixed appliance groups exhibited greater vertical dimension increases compared to clear aligner therapy. Overall, the study compared fixed appliances with clear aligner therapy and depicted clear aligners having better control of vertical dimension and distal tipping in molars when treated with miniscrew-assisted molar distalization approaches. | |
| Evidence Search |
PubMed: Clear aligner therapy AND molar distalization |
Comments on
The Evidence |
The systematic reviews and retrospective study create an overall body of evidence that supports clear aligner therapy as effective in achieving approximately 2-3 mm of distalization along with acceptable movement control. Confidence is improved by the consistency of the results throughout all three studies. Shen et al. and Disthaporn et al. increase the confidence of the result as they report similar measurements of distalization and identified molar tipping and anterior anchorage loss as possible treatment effects. The Wang et al. article demonstrated clear aligner therapy as capable of achieving similar amounts of distalization as compared to fixed appliances.
Despite the findings pointing towards a positive conclusion, the quality of the evidence is limited. The systematic reviews by Shen and Disthaporn report on about 50% of the same articles, which quantitatively limits the quality of evidence. Moreover, the systematic reviews and meta-analyses were developed on the bases of retrospective and non-randomized studies with a consistent moderate to high risk of bias within all the studies. Additionally, the substantial variability of methodology existing among studies, widely due to differences in aligner systems, limits the extent of meta-analyses that is available. Concurrently the studies highlight a need for future research with a focus on randomized trials that include standardized outcome measurements to improve certainty of the findings.
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| Applicability |
The findings of these studies are applicable to an orthodontic population with mild to moderate crowding that require maxillary molar distalization with non-extraction treatment approaches. The evidence suggests that treatment with clear aligner therapy can be expected to achieve approximately 2-3 mm of molar distalization while also being able to maintain acceptable movement control. Clear aligner therapy is gaining in popularity with the orthodontic population due to an increased amount of patient comfort, esthetic perception, and potentially better control of vertical dimension. The clinical applicability of the study can be limited due to the lack of randomized control trials and standardized measurement outcomes. |
| Specialty/Discipline |
(Orthodontics) |
| Keywords |
Molar Distalization, Clear Aligner therapy
|
| ID# |
3764 |
| Date of submission: |
06/14/2026 |
| E-mail |
Lozanoa7@livemail.uthscsa.edu |
| Author |
Arabellah Lozano |
| Co-author(s) |
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| Co-author(s) e-mail |
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| Faculty mentor/Co-author |
Kelly Lemke, DDS, MS |
| Faculty mentor/Co-author e-mail |
lemkek@uthscsa.edu |
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?) |
post a rationale |
| None available | |
|
Comments and Evidence-Based Updates on the CAT
(FOR PRACTICING DENTISTS', FACULTY, RESIDENTS and/or STUDENTS COMMENTS ON PUBLISHED CATs) |
post a comment |
| None available | |
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