Evidence map›Paper›PMID 42174193›Full record

ArticleClinical oral investigations2026

Three-dimensional stability during orthodontic retention: A comparative analysis of conventional, CAD/CAM-fabricated, and robotically bent fixed retainers versus removable appliances.

Jeannine Köck, Franziska Lang, Christian Niederau, Marta Rizk, Hannah Al-Sakati, Norbert Lang, Michael Wolf, Isabel Knaup

Abstract readComparative Study
In one paragraph

Article in Clinical oral investigations, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

8 authors.

Jeannine KöckDepartment of Orthodontics and Orofacial Orthopedics, RWTH Aachen University Hospital, Pauwelsstr. 30, Aachen, 52074, Germany.
Franziska LangDepartment of Orthodontics and Orofacial Orthopedics, RWTH Aachen University Hospital, Pauwelsstr. 30, Aachen, 52074, Germany.
Christian NiederauDepartment of Orthodontics and Orofacial Orthopedics, RWTH Aachen University Hospital, Pauwelsstr. 30, Aachen, 52074, Germany.
Marta RizkDepartment of Orthodontics and Orofacial Orthopedics, RWTH Aachen University Hospital, Pauwelsstr. 30, Aachen, 52074, Germany.
Hannah Al-SakatiDepartment of Orthodontics and Orofacial Orthopedics, RWTH Aachen University Hospital, Pauwelsstr. 30, Aachen, 52074, Germany.
Norbert LangDepartment of Orthodontics and Orofacial Orthopedics, RWTH Aachen University Hospital, Pauwelsstr. 30, Aachen, 52074, Germany.
Michael WolfDepartment of Orthodontics and Orofacial Orthopedics, RWTH Aachen University Hospital, Pauwelsstr. 30, Aachen, 52074, Germany.
Isabel KnaupDepartment of Orthodontics and Orofacial Orthopedics, RWTH Aachen University Hospital, Pauwelsstr. 30, Aachen, 52074, Germany. iknaup@ukaachen.de.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

objectivesTo evaluate three-dimensional anterior tooth position changes during orthodontic retention and to compare the effectiveness of three distinct fixed retainer fabrication designs including robotically bent retainers alongside with removable retainers. MATERIALS AND

methodsThis retrospective cohort study included 113 patients (226 dental arches; mean retention period 1.3 ± 0.6 years). Combined fixed lingual plus removable retention (group 1, n = 148 arches) comprised CAD/CAM Memotain, conventional multistranded stainless-steel (Twistflex), and robotically bent retainers; group 2 (n = 78 arches) received removable retention only. Digital model superimposition using a three-dimensional tooth-specific coordinate system quantified rotational and translational tooth movements, Little's Irregularity Index (LII), transverse arch widths, and bonding failures.

resultsCombined fixed and removable retention showed higher stability than removable-only retention (55% vs. 33% stable arches). Removable retention increased the odds of moderate-to-severe instability (maxilla OR 4.37, 95% CI 1.74-10.98; mandible OR 14.35, 95% CI 3.24-63.56), whereas fixed lingual retention was protective (maxilla OR 0.23, 95% CI 0.09-0.58; mandible OR 0.07, 95% CI 0.02-0.31). Instability mainly involved canine rotations and vertical translations. Robotically bent and CAD/CAM Memotain retainers showed the lowest movement magnitudes and variability, with minimal LII increases. Intercanine and intermolar widths remained stable across fixed retainers. Bonding failures (25%) strongly predicted severe instability.

conclusionsThree-dimensional tooth movements during retention mainly involve canine rotations and vertical translations. All fixed retainer designs (Twistflex, CAD/CAM-fabricated, and robotically bent) provided greater stability than removable-only retention. CLINICAL RELEVANCE: All fixed retainer designs require regular monitoring of bonding integrity; digitally fabricated and robotically bent retainers demonstrated marginally lower dimensional variability, which may be clinically relevant over longer observation periods.

Indexed as

Computer-Aided DesignOrthodontic Appliance DesignOrthodontic Appliances, RemovableOrthodontic RetainersRoboticsFemaleHumansMaleRetrospective StudiesCAD/CAM retainerFixed lingual retainerOrthodontic retentionThree-dimensional analysisTooth movementWire syndrome

Identifiers

PMID42174193
PMCPMC13197294

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.