Orthodontic Retention and Relapse: Current Concepts and Clinical Management
Dr. Vani Ravikumar, BDS, MDS (Orthodontics), FPFA, Fellow WFO *
*Correspondence to: Dr. Vani Ravikumar, BDS, MDS (Orthodontics), FPFA, Fellow WFO.
Copyright.
© 2026 Dr. Vani Ravikumar, This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Received: 22 August 2026
Published: 01 September 2026
DOI: https://doi.org/10.5281/zenodo.22241637
Abstract
Orthodontic treatment is followed by a period in which the dentition remains vulnerable to positional change. Some of this change represents true relapse toward the pretreatment arrangement, whereas other changes reflect maturation, ageing and continued adaptation of the dentofacial complex. Because these processes are difficult to predict for an individual patient, retention has become an integral part of orthodontic treatment rather than a short terminal stage. This narrative review discusses the biological basis of post-treatment change and the clinical use of removable and fixed retainers. Attention is given to Hawley and vacuum-formed retainers, bonded retainers, patient adherence, periodontal considerations, appliance failure and the duration of retention. Available evidence does not support a single retainer or wear schedule as the best option for every patient. Recent systematic reviews suggest that vacuum-formed and Hawley retainers have broadly comparable effects on arch dimensions, while fixed retainers may offer advantages for maintaining lower anterior alignment but require ongoing supervision. Bonded retainers also have a meaningful risk of failure, and distorted or partially detached wires can produce unwanted tooth movement. Retention should therefore be planned according to the original malocclusion, the extent and direction of tooth movement, periodontal status, anticipated compliance and patient priorities. Clear instructions, regular review and a realistic discussion of long-term retention are essential. In routine practice, the most appropriate strategy is usually not the retainer that appears theoretically superior, but the one that can reliably control the patient's principal stability risks and can be maintained safely over time. Patients should also understand that a retainer does not eliminate all future dental change. Long-term follow-up should therefore focus on both maintenance of alignment and early identification of retainer-related problems, particularly with bonded appliances. The review also emphasizes that retention decisions should be revisited when appliances fail, when the patient's circumstances change, or when clinically relevant tooth movement becomes apparent.
Keywords: orthodontic retention; relapse; orthodontic retainers; fixed retainers; vacuum-formed retainers
Review approach. This narrative review was informed by targeted searches of PubMed and by examination of recent systematic reviews, evidence-based reviews and selected clinical studies concerning orthodontic retention, relapse, fixed and removable retainers, periodontal outcomes, retainer failure and adherence. Priority was given to systematic reviews, randomized clinical trials and recent evidence published through August 2026. The purpose was to synthesize clinically relevant evidence rather than to perform a formal systematic review or meta-analysis.
Introduction
Orthodontic treatment changes the position of teeth within a biological system that continues to remodel after active appliances are removed. The expectation that teeth will remain permanently in their corrected positions without retention is therefore unrealistic. Long-term follow-up studies have shown that dental alignment may change for years after treatment, including in patients who initially achieved good correction. [1-3] Some of these changes are recognizable as relapse, while others are part of normal maturational change.
Retention is intended to hold the teeth in a clinically acceptable position while the supporting tissues adapt and, in the longer term, to manage the continuing tendency for dental change. The contemporary literature does not identify a universally optimal retention protocol. Instead, retainer type, design and wear schedule need to be considered in relation to pretreatment characteristics, treatment-induced changes and patient-related factors. [4,5]
This review provides a clinically focused synthesis of current evidence on orthodontic retention and relapse. It considers the biological basis of instability, the principal retainer types, retention regimens, patient adherence, periodontal implications, complications and practical approaches to long-term follow-up.
Why do teeth relapse after orthodontic treatment?
Post-treatment tooth movement has several overlapping causes. Immediately after appliance removal, the periodontal ligament and the supracrestal tissues are still adapting to the new tooth positions. Remodeling of these tissues does not occur instantaneously, and the remaining periodontal and gingival forces may contribute to early movement. Rotated teeth are particularly prone to positional change, which has been one reason why adjunctive procedures such as circumferential supracrestal fiberotomy have been investigated.[6]
Growth and maturation provide another source of change. Mandibular arch dimensions, incisor position and facial relationships can continue to alter after active treatment, particularly in younger patients. In adults, normal ageing is also associated with changes in tooth position. Long-term studies of untreated and treated populations indicate that mandibular anterior irregularity may increase with time even when there is no return to the exact pretreatment malocclusion. [2,3]
The extent of treatment-induced change also matters. Expansion, correction of rotations and movements that substantially alter the patient's original arch form may create a greater demand for retention. Nevertheless, relapse is not sufficiently predictable to allow clinicians to identify a small group of patients who can safely be considered 'no-retention' cases. [4,7]
Removable retainers
Hawley retainers
The Hawley retainer has remained in clinical use because it is durable, adjustable and relatively easy to repair. Its acrylic baseplate can be modified when minor tooth movement occurs, and the design permits some occlusal settling. Its principal disadvantages are visibility, the possibility of speech disturbance during the initial period of use and dependence on patient adherence.
A randomized controlled trial involving 397 patients compared Hawley and vacuum-formed retainers during the first six months of retention. The investigators found greater changes in incisor irregularity in the Hawley group, although differences in several other arch measurements were not statistically significant.[8] The study therefore supports the clinical effectiveness of both appliances while illustrating that differences between retainer designs may be outcome specific.
Vacuum-formed retainers
Vacuum-formed retainers (VFRs) are widely used because they are relatively discreet and provide close adaptation to the teeth. Their effectiveness is strongly dependent on fit, material properties and wear. They may also require replacement because of wear, fracture or loss of adaptation.
A 2024 systematic review and meta-analysis included 22 prospective studies involving 1,797 patients and compared VFRs with Hawley and fixed bonded retainers. The review found low- to moderate-certainty evidence that VFRs were broadly as effective as Hawley retainers in maintaining arch width, arch length and alignment. Compared with fixed bonded retainers, VFRs showed similar results for most outcomes, although fixed retainers were more effective for lower anterior alignment in the pooled analysis; the authors noted that the difference was not clinically significant.[9]
These findings are useful when counselling patients: a VFR is not simply an aesthetic alternative with inferior stability, but neither should it be described as universally superior to other retention methods. The decision should be based on the clinical objective and the patient's ability to use and maintain the appliance.
Fixed bonded retainers
Fixed retainers provide continuous mechanical retention without requiring the patient to remember daily insertion. They are particularly useful when prolonged control of the mandibular anterior teeth is considered important. Their main limitation is that the clinician must rely on the appliance remaining passive, intact and hygienically maintainable.
Bond failures and wire fractures are relatively common. A 2023 systematic review and meta-analysis of 34 studies reported an overall failure rate of approximately 35% after exclusion of high-risk studies, with failure increasing as follow-up became longer.[10] The finding does not mean that every fixed retainer will fail, but it demonstrates why patients with bonded retainers should not be discharged from all future review.
An additional concern is unwanted tooth movement associated with a distorted or partially detached retainer. Such movement can occur even when a retainer appears to remain attached to some teeth. The clinical consequences range from minor positional changes to more significant alterations that may require active orthodontic correction.[11] Patients should therefore be instructed to report changes in bite, tooth position, retainer tension or difficulty cleaning the bonded area.
Periodontal and oral hygiene considerations
Retention and periodontal health need to be considered together. Fixed retainers create additional surfaces around which plaque and calculus can accumulate, particularly in the mandibular anterior region. A systematic review comparing fixed and removable retainers found greater plaque and calculus accumulation with fixed appliances, although the clinical significance of these differences varied between studies.[12]
More recent evidence emphasizes a balanced interpretation. A 2024 review concluded that severe periodontal complications have been described with fixed retention, but a clear causal relationship between an intact passive retainer and periodontal breakdown has not been established.[5] The practical implication is not to avoid fixed retainers, but to provide appropriate oral-hygiene instruction and periodic professional assessment.
Patients with fixed retainers should be shown how to clean around the wire and should be assessed for calculus, gingival inflammation, bond failure, wire deformation and unwanted tooth movement. A removable retainer should likewise be kept clean and stored appropriately when not in use.
How long should retention continue?
Duration of retention remains one of the most debated aspects of orthodontic practice. Published protocols range from relatively intensive wear immediately after debonding followed by night-time wear to long-term night-time use from the outset. The available evidence does not justify one schedule for every patient. [4,5]
The important point is that the risk of tooth movement does not disappear at an arbitrary time point such as one or two years after treatment. Long-term observational evidence demonstrates continuing changes in dental alignment, and contemporary reviews consequently support prolonged retention for many patients. [1-5]
A practical approach is to use a more intensive regimen during the early post-treatment period, followed by a transition to night-time wear for removable retainers when appropriate. The exact regimen should be individualized. Patients should be told that retention may need to continue for many years and, where maintaining a particular tooth position is especially important, potentially for life.
Patient adherence
Removable retention introduces a behavioural component that is absent, or at least reduced, with fixed appliances. Self-reported wear may overestimate actual use, and adherence can decline as the interval from active treatment increases. Comfort, appearance, speech, convenience, forgetfulness and understanding of the purpose of retention all influence compliance.[4]
Simple interventions can make a meaningful difference. Instructions should be given verbally and in writing, with demonstration of insertion and removal. Patients should know how to clean the appliance, where to store it and what to do if it is lost or damaged. At follow-up visits, asking about actual wear rather than simply asking whether the retainer was used can help identify practical barriers.
Fixed versus removable retention: what does the evidence say?
The evidence does not support a blanket recommendation that fixed retention is better than removable retention, or vice versa. A 2023 Cochrane review found substantial heterogeneity across retention studies and judged much of the available evidence to be low or very low certainty.[7] A 2024 systematic review similarly found broadly comparable performance of VFRs and Hawley retainers for several arch dimensions, with some outcome-specific differences involving fixed retainers.[9]
More recent evidence continues to refine rather than overturn this position. A 2023 network meta-analysis comparing CAD/CAM and conventional fixed retainers found some short-term advantages for CAD/CAM designs in selected outcomes but emphasized the limited evidence for long-term durability.[13] A 2025 systematic review of smart retainers found that sensor-based monitoring can objectively measure wear, but pooled evidence did not demonstrate a consistent improvement in wear time.[14]
The clinical message is straightforward: choose the retention strategy according to the problem being controlled. A patient with a high risk of lower anterior relapse and reliable access to maintenance may be well suited to fixed retention, whereas another patient may prefer removable retainers because of oral hygiene, comfort or lifestyle. In some cases, combined fixed and removable retention is reasonable, but the additional benefit of routinely using both remains incompletely established.[4]
Practical retention protocol in routine practice
Retention should be discussed before the end of active treatment, not for the first time at the debonding appointment. Patients should understand the expected wear schedule, the likely duration of retention, the maintenance required and the possibility of replacement costs.
At retainer delivery, the clinician should check fit, comfort, occlusion and the patient's ability to insert and remove the appliance. For fixed retainers, each bonded segment should be inspected and the wire checked for passivity. Early review provides an opportunity to identify poor compliance, appliance damage and hygiene problems before they become clinically significant.
Long-term review can be less frequent once the patient is stable, but it should not necessarily cease. The interval should reflect the patient's relapse risk, retainer type, oral hygiene and ability to recognize problems. A patient with a fixed retainer should be advised that an apparently intact wire does not eliminate the need for periodic assessment.
Discussion
The central difficulty in orthodontic retention is that stability is not a single biological endpoint. The position of a tooth is influenced by periodontal remodeling, soft tissues, occlusal contacts, growth, maturation and ageing. This explains why studies with different follow-up periods and different outcome measures can reach apparently different conclusions.
Current evidence supports a conservative approach to retention because the individual risk of post-treatment change cannot be predicted with adequate precision. At the same time, the literature does not justify describing any retainer as maintenance-free. Removable appliances require adherence, while fixed appliances require professional monitoring and may fail or contribute to unwanted tooth movement if they become distorted.
The strongest practical principle is therefore individualized retention. The orthodontist should identify the principal stability risks created by the original malocclusion and treatment, discuss realistic expectations with the patient, select a retainer that can control those risks and establish a maintenance plan that is acceptable to the patient. This approach is more defensible than applying a single retention protocol to all patients.
Limitations of the current evidence
Research on orthodontic retention is difficult to compare because studies differ in retainer design, material, wear schedule, treatment type, follow-up duration and outcome measures. Many trials are relatively short, and long-term randomized evidence is limited. The 2023 Cochrane review highlighted concerns about risk of bias and low certainty across many comparisons.[7] Newer technologies such as CAD/CAM and sensor-enabled retainers are promising, but their long-term clinical advantages remain uncertain. [13,14]
These limitations should be acknowledged when translating research findings into clinical protocols. Retention recommendations should be updated as better long-term comparative evidence becomes available.
Conclusion
Relapse and other post-treatment tooth movements are common consequences of the continuing biological and maturational changes of the dentition. Retention should therefore be regarded as an integral part of orthodontic treatment. Fixed and removable retainers can both be effective, but neither is universally superior. The choice should reflect the patient's relapse risk, the movements achieved during treatment, periodontal health, anticipated adherence and personal preference. Long-term maintenance, clear patient instructions and regular assessment of retainer integrity are essential to reduce avoidable relapse and retainer-related complications.
Declarations
Ethics approval: Not applicable. This article is a narrative review of published literature and does not involve human participants or identifiable patient data.
Funding: No external funding was received for this work.
Conflict of interest: The author declares no conflict of interest.
Data availability: Not applicable.
Acknowledgements: None.
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