Non-Cochrane · intervention · PM42475394
Adverse effects of removable orthodontic aligners: A systematic review with single-arm meta-analysis.
Ronchi Lemos Cintia, Aguilar Ventura Fadel Marianella, Polmann Helena, et al. · PloS one · 2026 · PubMed · doi:10.1371/journal.pone.0350741
Findings
11 findings
| Population | ||||
|---|---|---|---|---|
| Orthodontic patients treated with removable clear aligners | Removable (clear) orthodontic aligners (aligner arm only) | None (single-arm meta-analysis) | Apical root resorption (linear, mm) 18 months · Overall | Mean change -0.69 [-0.96, -0.41] GRADE not reported 2 studies · 89 participants |
| Orthodontic patients treated with removable clear aligners | Removable (clear) orthodontic aligners (aligner arm only) | None (single-arm meta-analysis) | Apical root resorption (linear, mm) 6 months · Overall | Mean change -0.20 [-0.45, 0.05] Moderate Downgraded: risk of bias 3 studies · 125 participants |
| Orthodontic patients treated with removable clear aligners | Removable (clear) orthodontic aligners (aligner arm only) | None (single-arm meta-analysis) | Plaque Index change (Silness-Loe 0-3) 3 months · Conservative imputation of SD (primary) | Mean change 0.23 [-0.49, 0.95] Low Downgraded: risk of bias, imprecision 3 studies · 87 participants |
| Orthodontic patients treated with removable clear aligners | Removable (clear) orthodontic aligners (aligner arm only) | None (single-arm meta-analysis) | Apical root resorption (linear, mm) Baseline to 18 months · Subgroup by follow-up: baseline to 18 months | Mean change -0.31 [-0.53, -0.08] GRADE not reported 2 studies · 89 participants |
| Orthodontic patients of any age or sex treated with removable clear aligners | Removable clear aligner therapy (aligner arms only) | None (single-arm synthesis of aligner groups) | Pain/discomfort after aligner placement (VAS 0 to 10) 3 days · Clinical orthodontic settings, 15 countries | MEAN 1.55 [1.09, 2.21] Low Downgraded: risk of bias, inconsistency 7 studies · 259 participants |
| Orthodontic patients treated with removable clear aligners | Removable (clear) orthodontic aligners (aligner arm only) | None (single-arm meta-analysis) | Plaque Index change (Silness-Loe 0-3) 3 months · Optimistic imputation of SD (sensitivity) | Mean change 0.23 [-0.49, 0.94] GRADE not reported 3 studies · 87 participants |
| Orthodontic patients of any age or sex treated with removable clear aligners | Removable clear aligner therapy (aligner arms only) | None (single-arm synthesis of aligner groups) | Pain/discomfort after aligner placement (VAS 0 to 10) 1 week · Clinical orthodontic settings, 15 countries | MEAN 1.08 [0.33, 3.51] Very low Downgraded: risk of bias, imprecision, inconsistency 6 studies · 229 participants |
| Orthodontic patients of any age or sex treated with removable clear aligners | Removable clear aligner therapy (aligner arms only) | None (single-arm synthesis of aligner groups) | Pain/discomfort after aligner placement (VAS 0 to 10) 24 hours · Clinical orthodontic settings, 15 countries | MEAN 3.06 [2.15, 4.37] Very low Downgraded: risk of bias, imprecision, inconsistency 10 studies · 418 participants |
| Orthodontic patients treated with removable clear aligners | Removable (clear) orthodontic aligners (aligner arm only) | None (single-arm meta-analysis) | Apical root resorption (volumetric, mm3) End of follow-up · Overall | Mean change -4.37 [-5.51, -3.24] Moderate Downgraded: risk of bias 3 studies · 47 participants |
| Orthodontic patients treated with removable clear aligners | Removable (clear) orthodontic aligners (aligner arm only) | None (single-arm meta-analysis) | Apical root resorption (linear, mm) Baseline to 6 months · Subgroup by follow-up: baseline to 6 months | Mean change -0.06 [-0.35, 0.22] GRADE not reported 2 studies · 47 participants |
| Orthodontic patients treated with removable clear aligners | Removable (clear) orthodontic aligners (aligner arm only) | None (single-arm meta-analysis) | Apical root resorption (linear, mm) End of treatment (follow-up 6 to 26 months) · Overall (all follow-up subgroups) | Mean change -0.33 [-0.55, -0.11] Low Downgraded: risk of bias, inconsistency 6 studies · 216 participants |
Included primary studies 31
Open in Studies| Study | Year | Also included by | Outcomes it informs here | Trial data |
|---|---|---|---|---|
| Wang 2017 matched by author and year (probable) | NR | 2 other reviews | not stated | not extracted yet |
| Alam 2024 matched by author and year (probable) | NR | 1 other review | not stated | not extracted yet |
| Levrini 2013 matched by author and year (probable) | NR | 1 other review | Apical root resorption (volumetric, mm3) | not extracted yet |
| Withayanukonkij 2023 matched by author and year (probable) | NR | 1 other review | Plaque Index change (Silness-Loe 0-3); Apical root resorption (linear, mm) | not extracted yet |
| Yang 2023 matched by author and year (probable) | NR | 1 other review | not stated | not extracted yet |
| Zhang 2025 matched by author and year (probable) | NR | 1 other review | not stated | not extracted yet |
| Zhao 2023 matched by author and year (probable) | NR | 1 other review | Pain/discomfort after aligner placement (VAS 0 to 10) | not extracted yet |
| Al-Dboush 2022 matched by author and year (probable) | NR | this review only | Apical root resorption (linear, mm) | not extracted yet |
| Albhaisi 2020 matched by author and year (probable) | NR | this review only | not stated | not extracted yet |
| Alcón 2021 matched by author and year (probable) | NR | this review only | Pain/discomfort after aligner placement (VAS 0 to 10) | not extracted yet |
| Almagrami 2023 matched by author and year (probable) | NR | this review only | Plaque Index change (Silness-Loe 0-3) | not extracted yet |
| Almasoud 2018 matched by author and year (probable) | NR | this review only | Pain/discomfort after aligner placement (VAS 0 to 10) | not extracted yet |
| Altkuri 2024 matched by author and year (probable) | NR | this review only | Pain/discomfort after aligner placement (VAS 0 to 10) | not extracted yet |
| Antonio-Zancajo 2021 matched by author and year (probable) | NR | this review only | not stated | not extracted yet |
| Buschang 2019 matched by author and year (probable) | NR | this review only | not stated | not extracted yet |
| Çetin and Akdeniz 2025 matched by author and year (probable) | NR | this review only | not stated | not extracted yet |
| Damasceno Melo 2020 matched by author and year (probable) | NR | this review only | not stated | not extracted yet |
| Diddige 2019 matched by author and year (probable) | NR | this review only | Pain/discomfort after aligner placement (VAS 0 to 10) | not extracted yet |
| Eissa 2018 matched by author and year (probable) | NR | this review only | Plaque Index change (Silness-Loe 0-3); Apical root resorption (linear, mm) | not extracted yet |
| Fraundorf and Kim 2020 matched by author and year (probable) | NR | this review only | not stated | not extracted yet |
| Fujiyama 2014 matched by author and year (probable) | NR | this review only | Pain/discomfort after aligner placement (VAS 0 to 10) | not extracted yet |
| Khalil 2023 matched by author and year (probable) | NR | this review only | Apical root resorption (linear, mm) | not extracted yet |
| Liu & Song 2024 matched by author and year (probable) | NR | this review only | not stated | not extracted yet |
| Mahayyudin 2024 matched by author and year (probable) | NR | this review only | Plaque Index change (Silness-Loe 0-3); Apical root resorption (linear, mm) | not extracted yet |
| Mertoglu 2025 matched by author and year (probable) | NR | this review only | Plaque Index change (Silness-Loe 0-3); Apical root resorption (linear, mm); Apical root resorption (volumetric, mm3) | not extracted yet |
| Pereira 2020 matched by author and year (probable) | NR | this review only | not stated | not extracted yet |
| Rossi 2024 matched by author and year (probable) | NR | this review only | Apical root resorption (linear, mm) | not extracted yet |
| Rucker 2012 matched by author and year (probable) | NR | this review only | Pain/discomfort after aligner placement (VAS 0 to 10) | not extracted yet |
| Schaefer 2010 matched by author and year (probable) | NR | this review only | not stated | not extracted yet |
| Selvakumar 2024 matched by author and year (probable) | NR | this review only | Apical root resorption (volumetric, mm3) | not extracted yet |
| White 2017 matched by author and year (probable) | NR | this review only | Pain/discomfort after aligner placement (VAS 0 to 10) | not extracted yet |
Overlap with other reviews
Reviews that include the same primary studies are not independent evidence. Shared counts match studies by PMID, DOI or NCT, and otherwise by author and year (a probable match). Only the non-Cochrane dental reviews have study lists, so overlap with Cochrane reviews is not counted yet.
Review question
| Element | Planned (methods) | Found (results) |
|---|---|---|
| Population | Orthodontic patients of any age or sex | Orthodontic patients wearing clear aligners (n=1,636; mean age 13.9 to 45 years) |
| Intervention | Removable clear aligners | Removable clear aligners |
| Comparison | None (aligner arms only) | None (single-arm) |
| Outcomes | Adverse effects during or after aligner treatment | Pain/discomfort, apical root resorption, plaque (pooled); periodontal status, enamel demineralization, white spot lesions, speech, halitosis, open gingival embrasures, TMD, awake bruxism, caries, chewing performance (narrative) |
| Study designs | Cohort studies and clinical trials, randomized or not | 34 studies (10 RCTs, 6 non-randomized clinical studies, 18 cohort studies) |
| Timing | Not specified | Pain at 24 hours, 3 days, 1 week; plaque at 3 months; root resorption at 6 months, 18 months and end of treatment |
AMSTAR 2 items
Two independent extractors rated each item. Their ratings are shown side by side because they have not been reconciled yet. The overall rating follows Shea et al. 2017: one critical flaw gives Low, more than one gives Critically Low.
| Item | Extractor A | Extractor B | Agree |
|---|---|---|---|
| 1Research question includes PICO components | Yes | No | no |
| 2Protocol established before the reviewcritical | Partial Yes | Partial Yes | yes |
| 3Choice of study designs explained | No | No | yes |
| 4Comprehensive literature searchcritical | Yes | Yes | yes |
| 5Study selection in duplicate | Yes | Yes | yes |
| 6Data extraction in duplicate | Yes | Yes | yes |
| 7List of excluded studies with reasonscritical | Yes | Yes | yes |
| 8Included studies described in detail | Yes | Yes | yes |
| 9Risk of bias assessed satisfactorilycritical | RCT: Yes · NRSI: Yes | NRSI: Yes · RCT: Yes | no |
| 10Funding of included studies reported | Yes | Yes | yes |
| 11Appropriate meta-analysis methodscritical | RCT: Yes · NRSI: Partial Yes | NRSI: Yes · RCT: Yes | no |
| 12Impact of risk of bias on the pooled results | No | No | yes |
| 13Risk of bias accounted for in interpretationcritical | Yes | Yes | yes |
| 14Heterogeneity explained | Yes | Yes | yes |
| 15Publication bias investigatedcritical | No | No | yes |
| 16Conflicts of interest reported | Yes | Yes | yes |
| Overall | Low | Low | yes |