Retention constitutes a fundamental phase of orthodontic treatment, of which the patient must be made aware from the outset. Retention, which can be fixed or movable, has the task of maintaining over time and stabilising the results obtained during treatment. This study assessed the efficacy of using removable restraints versus fixed solutions for maintaining long-term outcomes. A comprehensive search across major databases—Pubmed, Web of Science, Scopus—used ‘relapse’ and ‘orthodontic’ as keywords to gather articles on relapse discussions. The primary focus was relapsed cases in post-fixed orthodontic therapy. Both fixed and removable retainer systems prove effective in preserving orthodontic achievements. While fixed devices require regular wire integrity checks, mobile devices require patient compliance, proper usage, and a recommended wear time. Studies indicate that fixed retainers are generally successful, with relapse rates varying based on the retainer type. Full-time use of removable devices surpasses night-only wear. Vacuum-formed and Hawley retainers offer similar effectiveness. Fixed retainers excel in long-term alignment stability, whereas removable ones have higher failure rates yet remain beneficial.

Relapse is one of the commonest risk factors in orthodontics. Post-treatment changes following orthodontics could be due to periodontal or occlusal factors, but they can also be due to soft tissue changes and growth. Soft tissue changes and growth are beyond an orthodontist's control, and this explains the unpredictable nature of orthodontic relapse. Patients need to be informed of the unpredictable nature of relapse before they begin treatment, and the possible need for long-term retention to help reduce the amount of relapse.

The present systematic review aimed to evaluate and compare the post-treatment relapse of overjet, overbite, and mandibular incisor crowding in patients treated with extraction and non-extraction orthodontic approaches and to assess the influence of treatment modality on long-term stability. The review was conducted following PRISMA guidelines. Data were extracted from 10 studies, including retrospective and longitudinal designs, with a total of 720 participants. The primary outcome measures included overjet, overbite, and Little's Irregularity Index. Standardized mean difference (SMD) was used as the summary statistic to compare extraction and non-extraction groups. The risk of bias was assessed using the ROBINS-I tool. The meta-analysis revealed no statistically significant differences in relapse between extraction and non-extraction groups for overjet (SMD: 0.52, 95% CI: -0.18 to 1.23, p>0.05), overbite (SMD: 0.41, 95% CI: -0.11 to 0.93, p>0.05), and incisor irregularity index (SMD: 0.71, 95% CI: -0 to 1.23, p>0.05). Funnel plots indicated no significant publication bias. Risk of bias assessment showed moderate concerns in confounding and participant selection across several studies, while bias due to missing data was notable in longer follow-up studies. The findings suggest that both extraction and non-extraction treatment approaches exhibit similar post-treatment relapse rates for overjet, overbite, and incisor irregularity. The choice of treatment should be based on clinical considerations along with concerns of long-term stability. Further high-quality randomized controlled trials are required to strengthen the evidence.

Orthodontists must fully inform patients about the implications of orthodontic treatment and the subsequent need for retention. This review provides an update on relapse, unwanted movements and different factors that can cause loss of stability following orthodontic treatment. Since it is difficult to predict which patients will present some degree of loss of stability after treatment, it is important that they be treated as if they have a high potential for relapse. The present review included a bibliographic search in the main sources of scientific review including Medline via PubMed, Scopus and the Cochrane library. The search strategy was carried out until May 5, 2022. Only 34 studies fulfilling the selection criteria. Our results showed that maintaining teeth in the correct position following orthodontic treatment is a great challenge for orthodontists. The etiology of relapse is complex and not yet clearly established. Its origin is attributed to factors such as the time of gingival and periodontal tissue reorganization and changes produced by growth, compromising the stability of the results achieved with orthodontic treatment. The retention phase is necessary after orthodontic treatment to avoid relapse or loss of the occlusion results obtained. However, fixed retainers may induce unwanted tooth movement that may occur despite these retainers being attached and intact. There is currently no consensus among orthodontists regarding the ideal type of wire for fixed containment. We concluded that post-orthodontic treatment relapse is the result of a regression towards the original malocclusion. However, changes in the position of the teeth can also occur, which are considered as unwanted movements and have a multifactorial origin.

<b>Objectives:</b> Despite the widespread adoption of clear aligner therapy (CAT), its effectiveness in managing rotations remains debated. This systematic review aims to evaluate rotational accuracy in adults and the influence of treatment variables-such as attachments, interproximal reduction (IPR), and staging. <b>Methods</b>: Following PRISMA guidelines, seven databases and two grey literature sources were searched up to July 2025. Eligible studies assessed rotational accuracy in patients treated exclusively with clear aligners, using 3D digital model superimposition. Primary outcomes included percent accuracy, lack of correction (LC), or mean absolute error (MAE). Risk of bias (RoB 2, ROBINS-I) and certainty of evidence (GRADE) were assessed. <b>Results</b>: Twelve studies (one RCT, eleven non-randomized) were included, showing wide heterogeneity in aligner systems, tooth types, outcome measures, and adjunctive strategies. Reported accuracy ranged from 36% to 85%, averaging around 65%. LC values varied from 0.7° to 4.5°, and mean MAE was about 2.3°. Incisors and molars showed higher predictability, whereas maxillary canines and premolars remained the least reliable. Attachments and IPR were widely used, but their effectiveness was inconsistent. Staging protocols were generally set at 2°/aligner and most studies adopted 7-14-day wear schedules. Nearly all investigations showed moderate-to-serious risk of bias, and certainty of evidence was rated low to moderate. <b>Conclusions</b>: CAT shows limited yet improving predictability in rotational movements, with performance strongly influenced by tooth morphology and staging. Attachments, IPR, and overcorrections may contribute but lack consistent validation. Given the low certainty and high risk of bias of current evidence, these findings should be interpreted cautiously. Well-designed RCTs with standardized protocols are required to develop reliable clinical guidelines.

<i>Background and Objectives</i>: Anterior open-bite malocclusion remains a challenging orthodontic condition where achieving a positive overbite necessitates precise control of incisor extrusion and molar intrusion. With recent advances in clear aligner therapy-improved materials, attachment techniques and digital treatment planning-the potential for non-invasive treatment has increased. This scoping review systematically maps the evidence on the efficacy of clear aligners in treating anterior open bite among adult patients, outlines treatment protocols and highlights gaps in the literature. <i>Materials and Methods</i>: A systematic search was conducted in PubMed/Medline, Embase/ScienceDirect and Clarivate/Web of Science for literature published in English between January 2000 and December 2024. Studies involving adult patients treated with clear aligners (predominantly Invisalign^®) were included. A two-step screening process was applied, and data were charted according to pre-specified criteria. The review adheres to the PRISMA-ScR checklist guidelines. <i>Results</i>: From an initial pool of 802 articles, 30 met the inclusion criteria following duplicate removal and full-text screening. The evidence suggests that clear aligners can achieve measurable incisor extrusion and posterior intrusion when appropriate auxiliary techniques (e.g., attachments and mini screws) are used. However, digital treatment planning software may overestimate movement predictions, necessitating iterative refinement phases. Patient compliance, clinician expertise and technological limitations are key factors influencing outcomes. <i>Conclusions</i>: Clear aligner therapy represents a promising alternative to fixed appliances for anterior open-bite correction in adults, although challenges remain in achieving precise vertical control. Further high-quality randomized controlled trials and standardized outcome measures are needed to confirm long-term stability and efficacy.