Non-Cochrane · intervention · PM42458363
Effects of different orthodontic retainers on dental arch stability and periodontal health: a systematic review with pairwise meta-analysis and network meta-analysis.
Zhang Xiaochen, Li Ying, Zhang Zhen, et al. · BMC oral health · 2026 · PubMed · doi:10.1186/s12903-026-09123-7
Findings
49 findings
| Population | ||||
|---|---|---|---|---|
| Patients who completed orthodontic treatment and entered the retention phase | Removable retainers (Hawley and vacuum-formed) | Fixed retainers | Gingival index (GI) Follow-up 3 to 24 months pooled · Sensitivity analysis excluding studies at high overall risk of bias | MD 0.04 [-0.03, 0.12] GRADE not reported 2 studies |
| Patients who completed orthodontic treatment and entered the retention phase | Removable retainers (Hawley and vacuum-formed) | Fixed retainers | Little's irregularity index (LII) Follow-up 3 to 24 months pooled · Sensitivity analysis excluding studies at high overall risk of bias | MD 0.47 [0.11, 0.82] GRADE not reported 3 studies |
| Patients who completed orthodontic treatment and entered the retention phase | Removable retainers (Hawley and vacuum-formed) | Fixed retainers | Intercanine distance (ICD) Follow-up 3 to 24 months pooled | MD -0.11 [-0.22, -0.00] Low 3 studies |
| Patients who completed orthodontic treatment and entered the retention phase | Removable retainers (Hawley and vacuum-formed) | Fixed retainers | Arch length (AL) Sensitivity analysis excluding studies at high overall risk of bias | No direct fixed-versus-removable comparison remained; sensitivity analysis not estimable No studies found 0 studies |
| Patients who completed orthodontic treatment and entered the retention phase | Removable retainers (Hawley and vacuum-formed) | Fixed retainers | Plaque index (PI) Follow-up 3 to 24 months pooled · Sensitivity analysis excluding studies at high overall risk of bias | MD -0.04 [-0.15, 0.06] GRADE not reported 2 studies |
| Patients who completed orthodontic treatment and entered the retention phase | Removable retainers (Hawley and vacuum-formed) | Fixed retainers | Little's irregularity index (LII) Follow-up 3 to 24 months pooled | MD 0.24 [-0.14, 0.62] Very low 4 studies |
| Patients who completed orthodontic treatment and entered the retention phase | Removable retainers (Hawley and vacuum-formed) | Fixed retainers | Interpremolar distance (IPD) Sensitivity analysis excluding studies at high overall risk of bias | No direct fixed-versus-removable comparison remained; sensitivity analysis not estimable No studies found 0 studies |
| Patients who completed fixed orthodontic treatment and entered the retention phase | Removable retainers (Hawley or vacuum-formed) | Fixed retainers | Gingival index (GI) Follow-up 3 to 24 months across studies (pooled) | MD 0.04 [-0.03, 0.12] Moderate 2 studies |
| Patients who completed orthodontic treatment and entered the retention phase | Removable retainers (Hawley and vacuum-formed) | Fixed retainers | Arch length (AL) Follow-up 3 to 24 months pooled | MD 0.42 [0.24, 0.60] Low 2 studies |
| Patients who completed fixed orthodontic treatment and entered the retention phase | Removable retainers (Hawley or vacuum-formed) | Fixed retainers | Plaque index (PI) Follow-up 3 to 24 months across studies (pooled) | MD -0.04 [-0.15, 0.06] Moderate 2 studies |
| Patients who completed orthodontic treatment and entered the retention phase | Conventional fixed retainers | CAD/CAM fixed retainers | Interpremolar distance (IPD) Follow-up 3 to 24 months pooled | MD 0.06 [-0.51, 0.65] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Conventional fixed retainers | CAD/CAM fixed retainers | Intercanine distance (ICD) Follow-up 3 to 24 months pooled | MD -0.28 [-0.83, 0.21] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Conventional fixed retainers | CAD/CAM fixed retainers | Plaque index (PI) Follow-up 3 to 24 months pooled | MD 0 [-0.24, 0.23] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Conventional fixed retainers | CAD/CAM fixed retainers | Little's irregularity index (LII) Follow-up 3 to 24 months pooled | MD 0.44 [-0.24, 1.16] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Conventional fixed retainers | CAD/CAM fixed retainers | Complications Follow-up 3 to 24 months pooled | RR 0.99 [0.62, 1.61] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Conventional fixed retainers | CAD/CAM fixed retainers | Gingival index (GI) Follow-up 3 to 24 months pooled | MD -0.08 [-1.26, 1.2] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Conventional fixed retainers | CAD/CAM fixed retainers | Arch length (AL) Follow-up 3 to 24 months pooled | MD -0.07 [-0.89, 0.73] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Hawley retainers | CAD/CAM fixed retainers | Arch length (AL) Follow-up 3 to 24 months pooled | MD 0.27 [-2.1, 2.62] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Hawley retainers | CAD/CAM fixed retainers | Intercanine distance (ICD) Follow-up 3 to 24 months pooled | MD -0.54 [-1.51, 0.39] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Hawley retainers | CAD/CAM fixed retainers | Little's irregularity index (LII) Follow-up 3 to 24 months pooled | MD 0.99 [-0.13, 2.2] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Hawley retainers | CAD/CAM fixed retainers | Gingival index (GI) Follow-up 3 to 24 months pooled | MD -0.02 [-2.02, 2.05] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Hawley retainers | CAD/CAM fixed retainers | Interpremolar distance (IPD) Follow-up 3 to 24 months pooled | MD -0.12 [-2.79, 2.49] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Hawley retainers | CAD/CAM fixed retainers | Plaque index (PI) Follow-up 3 to 24 months pooled | MD -0.06 [-0.43, 0.31] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Vacuum-formed retainers | CAD/CAM fixed retainers | Little's irregularity index (LII) Follow-up 3 to 24 months pooled | MD 0.63 [-0.33, 1.7] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Vacuum-formed retainers | CAD/CAM fixed retainers | Intercanine distance (ICD) Follow-up 3 to 24 months pooled | MD -0.34 [-1.07, 0.40] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Vacuum-formed retainers | CAD/CAM fixed retainers | Complications Follow-up 3 to 24 months pooled | RR 1 [0.15, 6.68] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Vacuum-formed retainers | CAD/CAM fixed retainers | Plaque index (PI) Follow-up 3 to 24 months pooled | MD -0.04 [-0.35, 0.26] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Vacuum-formed retainers | CAD/CAM fixed retainers | Interpremolar distance (IPD) Follow-up 3 to 24 months pooled | MD -0.14 [-2.28, 1.96] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Vacuum-formed retainers | CAD/CAM fixed retainers | Gingival index (GI) Follow-up 3 to 24 months pooled | MD -0.03 [-1.72, 1.74] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Vacuum-formed retainers | CAD/CAM fixed retainers | Arch length (AL) Follow-up 3 to 24 months pooled | MD 0.34 [-0.62, 1.28] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Hawley retainers | Conventional fixed retainers | Arch length (AL) Follow-up 3 to 24 months pooled | MD 0.34 [-1.84, 2.56] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Hawley retainers | Conventional fixed retainers | Gingival index (GI) Follow-up 3 to 24 months pooled | MD 0.05 [-1.58, 1.67] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Hawley retainers | Conventional fixed retainers | Plaque index (PI) Follow-up 3 to 24 months pooled | MD -0.06 [-0.34, 0.23] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Hawley retainers | Conventional fixed retainers | Intercanine distance (ICD) Follow-up 3 to 24 months pooled | MD -0.26 [-1.03, 0.58] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Hawley retainers | Conventional fixed retainers | Interpremolar distance (IPD) Follow-up 3 to 24 months pooled | MD -0.18 [-2.79, 2.39] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Hawley retainers | Conventional fixed retainers | Little's irregularity index (LII) Follow-up 3 to 24 months pooled | MD 0.55 [-0.36, 1.5] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Vacuum-formed retainers | Conventional fixed retainers | Interpremolar distance (IPD) Follow-up 3 to 24 months pooled | MD -0.21 [-2.26, 1.81] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Vacuum-formed retainers | Conventional fixed retainers | Little's irregularity index (LII) Follow-up 3 to 24 months pooled | MD 0.19 [-0.51, 0.95] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Vacuum-formed retainers | Conventional fixed retainers | Intercanine distance (ICD) Follow-up 3 to 24 months pooled | MD -0.08 [-0.54, 0.54] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Vacuum-formed retainers | Conventional fixed retainers | Plaque index (PI) Follow-up 3 to 24 months pooled | MD -0.04 [-0.24, 0.15] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Vacuum-formed retainers | Conventional fixed retainers | Arch length (AL) Follow-up 3 to 24 months pooled | MD 0.41 [-0.13, 0.94] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Vacuum-formed retainers | Conventional fixed retainers | Gingival index (GI) Follow-up 3 to 24 months pooled | MD 0.04 [-1.16, 1.27] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Vacuum-formed retainers | Conventional fixed retainers | Complications Follow-up 3 to 24 months pooled | RR 1.01 [0.16, 6.34] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Vacuum-formed retainers | Hawley retainers | Plaque index (PI) Follow-up 3 to 24 months pooled | MD 0.02 [-0.29, 0.31] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Vacuum-formed retainers | Hawley retainers | Gingival index (GI) Follow-up 3 to 24 months pooled | MD -0.01 [-1.63, 1.61] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Vacuum-formed retainers | Hawley retainers | Little's irregularity index (LII) Follow-up 3 to 24 months pooled | MD -0.36 [-1.19, 0.49] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Vacuum-formed retainers | Hawley retainers | Interpremolar distance (IPD) Follow-up 3 to 24 months pooled | MD -0.03 [-1.65, 1.58] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Vacuum-formed retainers | Hawley retainers | Arch length (AL) Follow-up 3 to 24 months pooled | MD 0.07 [-2.09, 2.2] GRADE not reported Studies not reported |
| Patients who completed orthodontic treatment and entered the retention phase | Vacuum-formed retainers | Hawley retainers | Intercanine distance (ICD) Follow-up 3 to 24 months pooled | MD 0.20 [-0.37, 0.82] GRADE not reported Studies not reported |
Included primary studies 18
Open in Studies| Study | Year | Also included by | Outcomes it informs here | Trial data |
|---|---|---|---|---|
| Gelin 2020 Innovative customized CAD/CAM nickel-titanium lingual retainer versus standard stainless-steel lingual retainer: A randomized controlled… PMID:33144526 | 2020 | 1 other review | not stated | not extracted yet |
| Ashari 2022 A two-year comparative assessment of retention of arch width increases between modified vacuum-formed and Hawley retainers: a multi-center… PMID:36018418 | 2022 | this review only | not stated | not extracted yet |
| Atack 2007 Which way forward? Fixed or removable lower retainers. PMID:18004927 | 2007 | this review only | not stated | not extracted yet |
| Demir 2012 Comparison of retention characteristics of Essix and Hawley retainers. PMID:23173119 | 2012 | this review only | not stated | not extracted yet |
| Elhosseiny 2025 Effectiveness of CAD/CAM titanium fixed lingual retainer versus conventional stainless steel fixed retainer (randomized controlled… PMID:40528130 | 2025 | this review only | not stated | not extracted yet |
| Eroglu 2018 Comparative evaluation of salivary microbial levels and periodontal status of patients wearing fixed and removable orthodontic retainers. PMID:31375228 | 2019 | this review only | not stated | not extracted yet |
| Gera 2023 Stability, survival, and patient satisfaction with CAD/CAM versus conventional multistranded fixed retainers in orthodontic patients: a… PMID:35964235 | 2023 | this review only | not stated | not extracted yet |
| Jasim 2024 Poly-ether-ether-ketone (PEEK) versus dead-soft coaxial bonded retainers: a randomized clinical trial. Part 1. Stability, retainer… PMID:39206494 | 2024 | this review only | not stated | not extracted yet |
| Kartal 2020 Comparative evaluation of periodontal effects and survival rates of Memotain and five-stranded bonded retainers : A prospective short-term… PMID:32780168 | 2021 | this review only | not stated | not extracted yet |
| Kramer 2019 Vacuum-formed retainer versus bonded retainer for dental stabilization in the mandible-a randomized controlled trial. Part I: retentive… PMID:31665279 | 2020 | this review only | not stated | not extracted yet |
| Maskim 2025 A randomized controlled trial comparing retainers in bimaxillary proclination cases. PMID:39912971 | 2025 | this review only | not stated | not extracted yet |
| Naraghi 2023 Stability of maxillary anterior teeth during retention and 1 year after removal of retention-an RCT on adolescents retained with two… PMID:37119264 | 2023 | this review only | not stated | not extracted yet |
| O'Rourke 2016 Effectiveness of bonded and vacuum-formed retainers: A prospective randomized controlled clinical trial. PMID:27585768 | 2016 | this review only | not stated | not extracted yet |
| Pullisaar 2024 Stability, survival, patient satisfaction, and cost-minimization of CAD/CAM versus conventional multistranded fixed retainers in… PMID:38394353 | 2024 | this review only | not stated | not extracted yet |
| Rowland 2006 The effectiveness of Hawley and vacuum-formed retainers: a single-center randomized controlled trial. PMID:18068589 | 2007 | this review only | not stated | not extracted yet |
| Tabellion 2025 Post-treatment stability after insertion of CAD/CAM fabricated or Conventional fixed orthodontic retainers: a two-year follow-up. PMID:40347399 | 2025 | this review only | not stated | not extracted yet |
| Tran 2024 Relapse and failure rates between CAD/CAM and conventional fixed retainers: a 2-year follow-up of a randomized controlled clinical trial. PMID:38168815 | 2024 | this review only | not stated | not extracted yet |
| Ugrin 2024 Comparison of efficacy of thermoplastic retainer with round and rectangular bonded lingual wire retainer in the mandible two years after… PMID:38424224 | 2024 | this review only | not stated | 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 | Shared studies | Jaccard |
|---|---|---|
| Effect of Direct Versus Indirect Bonding Techniques on Fixed Retainer Failure Rates: A Systematic Review and Meta-Analysis. (2026) | 1 | 0.03 |
Review question
| Element | Planned (methods) | Found (results) |
|---|---|---|
| Population | Patients who completed active orthodontic treatment and required retention (adolescents or adults, any sex) | Patients who completed fixed orthodontic treatment and entered the retention phase (n=1,471; 18 RCTs) |
| Intervention | Orthodontic retainers: conventional fixed (FRs), CAD/CAM fixed (CAD/CAM FRs), vacuum-formed (VFRs), Hawley (HRs) | CAD/CAM FRs, FRs, VFRs, HRs (one trial also had a dual retention FR plus VFR arm) |
| Comparison | Other eligible retainer types within the network; fixed versus removable retainers in pairwise comparisons | Fixed versus removable retainers (pairwise); FRs vs CAD/CAM FRs, VFRs vs FRs, HRs vs FRs, HRs vs VFRs (network) |
| Outcomes | Dental arch stability (arch length, Little irregularity index, intercanine distance, interpremolar distance), periodontal health (gingival index, plaque index), retainer-related complications | GI, PI, AL, LII, ICD, IPD, complications |
| Study designs | RCTs | RCTs (n=18) |
| Timing | Not specified | Follow-up 3 to 24 months |
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 | Yes | yes |
| 2Protocol established before the reviewcritical | Partial Yes | Partial Yes | yes |
| 3Choice of study designs explained | No | No | yes |
| 4Comprehensive literature searchcritical | No | Partial Yes | no |
| 5Study selection in duplicate | Yes | Yes | yes |
| 6Data extraction in duplicate | Yes | Yes | yes |
| 7List of excluded studies with reasonscritical | No | No | yes |
| 8Included studies described in detail | Partial Yes | Partial Yes | yes |
| 9Risk of bias assessed satisfactorilycritical | RCT: Yes · NRSI: N/A | NRSI: N/A · RCT: Yes | no |
| 10Funding of included studies reported | No | No | yes |
| 11Appropriate meta-analysis methodscritical | RCT: Yes · NRSI: N/A | NRSI: N/A · RCT: Yes | no |
| 12Impact of risk of bias on the pooled results | Yes | Yes | yes |
| 13Risk of bias accounted for in interpretationcritical | Yes | Yes | yes |
| 14Heterogeneity explained | Yes | Yes | yes |
| 15Publication bias investigatedcritical | Yes | Yes | yes |
| 16Conflicts of interest reported | Yes | Yes | yes |
| Overall | Critically Low | Low | no |