1
|
Hussain U, Kunwar SS, Khan UW, Alnazeh AA, Kamran MA, Alam S, Aziz A, Zaheen M, Pandis N, Campobasso A. Can vacuum-formed retainers maintain arch dimensions and alignment compared to Hawley and fixed bonded retainers after treatment with fixed appliances? A systematic review and meta-analysis. Eur J Orthod 2024; 46:cjae040. [PMID: 39177154 DOI: 10.1093/ejo/cjae040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/24/2024]
Abstract
BACKGROUND Different types of retention appliances have been proposed over the years, but their effectiveness in maintaining arch dimensions and alignment after orthodontic treatment is still unclear. AIM To assess the efficacy of vacuum-formed retainers (VFRs) in preserving arch widths, arch length, and anterior alignment in maxillary and mandibular arches, compared to removable Hawley retainers (HRs) or fixed bonded retainers (FBRs). Search methods: unrestricted literature search of five major databases up to March 2024. SELECTION CRITERIA randomized/non-randomized clinical studies comparing VFRs to removable HRs or FBRs. DATA COLLECTION AND ANALYSIS after duplicate study selection, data extraction, and risk of bias assessment, random effects meta-analyses of standardized mean differences and their 95% confidence intervals were performed, followed by meta-regressions, sensitivity analyses, and assessment of the quality of evidence with GRADE. RESULTS Twenty-two prospective studies (4 non-randomized and 18 randomized controlled trials) involving 1797 patients (mean age 17.01 years, 38.3% males) were included. No significant differences were found in the intercanine width, intermolar width, and arch length between VFRs and HRs, in both arches (P > 0.05). However, VFRs were statistically more effective than HRs in terms of Little's irregularity scores (LII) in the maxilla (eight studies; SMD = -0.42; 95% CI: -1.03 to -0.09; P = 0.02; I2 = 73.4%) but not in the mandible (P = 0.12). No significant differences were reported for all considered outcomes between VFRs and FBRs in in both arches (P > 0.05), except for lower LII, where VFRs were significantly less efficient (eight studies; SMD = 1.49; 95% CI = 0.26-2.7; P = 0.02; I2 = 93%). Follow-up times, risk of bias, and wire type (of FBRs) did not show statistically significant effects on outcome variables. Sensitivity analyses showed robustness of the findings for including non-randomized and postretention studies. The certainty in these estimates was from moderate to low due to the risk of bias and inconsistency. CONCLUSIONS Low to moderate quality evidence indicates that VFRs are as effective as HRs in maintaining arch widths, length, and alignment. Low-quality evidence found similar efficacy between VFRs and FBRs, with FBRs being statistically more effective at maintaining lower arch alignment, but the difference was not clinically significant. REGISTRATION PROSPERO registration (CRD42024518433).
Collapse
Affiliation(s)
- Umar Hussain
- Department of Orthodontics, Saidu College of Dentistry, Swat, Khyber Pakhtunkhwa 19200, Pakistan
| | | | - Umair Wali Khan
- Orthodontics, Altamash Institute of Dental Medicine, Karachi, Pakistan
| | - Abdullah A Alnazeh
- Department of Pediatric Dentistry and Orthodontic, Sciences College of Dentistry, King Khalid University, Abha, Saudi Arabia
| | - Muhammad Abdullah Kamran
- Department of Pedodontics and Orthodontic Sciences, College of Dentistry, King Khalid University, Abha, Saudi Arabia
| | | | - Anum Aziz
- Orthodontics Department, Avicenna Dental College and Hospital, Lahore, Pakistan
| | - Muhammad Zaheen
- Department of Orthodontics, Saidu College of Dentistry, Swat, Khyber Pakhtunkhwa 19200, Pakistan
| | - Nikolaos Pandis
- Department of Orthodontics and Dentofacial Orthopedics, Dental School/Medical Faculty, University of Bern, Bern, Switzerland
| | - Alessandra Campobasso
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy
| |
Collapse
|
2
|
Sonesson M, Naraghi S, Bondemark L. Cost analysis of two types of fixed maxillary retainers and a removable vacuum-formed maxillary retainer: a randomized controlled trial. Eur J Orthod 2022; 44:197-202. [PMID: 35021204 PMCID: PMC8965225 DOI: 10.1093/ejo/cjab080] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND There has been an increased interest in conducting healthcare economic evaluations. Also, orthodontic treatments have gathered focus from an economic point of view, however orthodontic research seldom examines both clinical and economic outcomes. OBJECTIVE To evaluate and compare the costs of three retention methods: a bonded retainer to the maxillary four incisors, a bonded retainer to the maxillary four incisors and canines, and a removable vacuum-formed retainer (VFR) in the maxilla. The null hypothesis was that there was no difference in costs for the three types of retention methods. TRIAL DESIGN Three-arm, parallel group, single-centre, randomized controlled trial. MATERIALS AND METHODS Ninety adolescent patients, 54 girls and 36 boys, treated with fixed or removable retainers in the maxilla, were recruited to the study. The patients were randomized in blocks of 30, by an independent person, to one of three groups: bonded multistranded PentaOne (Masel Orthodontics) retainer 13-23, bonded multistranded PentaOne (Masel Orthodontics) retainer 12-22, and removable VFR. A cost analysis was made regarding chair time costs based on the costs per hour for the specialist in orthodontics, and material costs plus any eventual costs for repairs of the appliance. Changes in Little's irregularity index and in single contact point discrepancies (CPDs) were measured on digitalized three-dimensional study casts. Data were evaluated on an intention-to-treat basis. The analysis was performed at 2 years of retention. RESULTS No statistically significant difference in costs between the maxillary fixed retainers and the VFRs was found, however, the material and emergency costs were significantly higher for the VFR compared with the bonded retainers. All three retention methods showed equally effective retention capacity, and no statistically significant differences in irregularity or CPDs of the maxillary anterior teeth in the three groups was detected. LIMITATIONS It was a single-centre trial, and hence less generalizable. Costs depended on local factors, and consequently, cannot be directly transferred to other settings. CONCLUSIONS All three retention methods can be recommended when considering costs and retention capacity. TRIAL REGISTRATION NCT04616755.
Collapse
Affiliation(s)
- Mikael Sonesson
- Department of Orthodontics, Faculty of Odontology, Malmö University, Sweden
| | - Sasan Naraghi
- Department of Orthodontics, Faculty of Odontology, Malmö University, Sweden
- Orthodontic Clinic, Public Dental Health, Växjö, Sweden
| | - Lars Bondemark
- Department of Orthodontics, Faculty of Odontology, Malmö University, Sweden
| |
Collapse
|
3
|
Bellini-Pereira SA, Aliaga-Del Castillo A, Dos Santos CCO, Henriques JFC, Janson G, Normando D. Treatment stability with bonded versus vacuum-formed retainers: a systematic review of randomized clinical trials. Eur J Orthod 2021; 44:187-196. [PMID: 34719722 DOI: 10.1093/ejo/cjab073] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND In orthodontics, the retention phase can be considered challenging and unpredictable. Therefore, evidence obtained from different retention protocols is important to facilitate clinical decision-making. OBJECTIVES This systematic review aimed to compare the clinical effectiveness of bonded versus vacuum-formed retainers (VFRs) regarding their capacity to maintain treatment stability, periodontal effects, and failure rates. SEARCH METHODS AND ELIGIBILITY CRITERIA Ten databases comprising published and unpublished literature were systematically searched up to August 2021. Randomized clinical trials (RCTs) comparing both retainers were included. DATA COLLECTION AND ANALYSIS The risk of bias (RoB) evaluation was performed with the Cochrane Collaboration RoB Tool 2.0. All steps of the screening phase and RoB assessment were performed independently by two reviewers. The Grade of Recommendations, Assessment, Development, and Evaluation (GRADE) was used to evaluate the certainty of the evidence. RESULTS Initial database search yielded 923 studies. After duplicates removal and full-text assessment, five RCTs remained. Overall, the studies presented Low RoB, except one study judged with 'Some concerns'. Based on the included studies, on a short-term (3-6 months) and long-term (4 years) basis, bonded retainers (BRs) were more effective to maintain treatment stability than VFRs in the lower arch. However, from 12 to 24 months both retainers presented the same efficacy. In the upper arch, the retainers were equally effective. BRs were associated with greater plaque and calculus accumulation than VFRs after 12 months. The retainers' failure rates were similar in the upper arch on the first year of retention; however, after 2 years VFRs showed significantly greater failure rates. Contrarily, BRs presented greater failure rates in the lower arch than VFRs. LIMITATIONS The findings of the included studies may be influenced by different factors related to the unpredictability of relapse. CONCLUSIONS Most of the evidence generated in this systematic review derived from a moderate level of certainty. In the lower arch, BRs are more effective than VFRs to maintain treatment stability in the initial 6 months of retention and in the long term. In the upper arch, both retention protocols are equally effective. REGISTRATION Regist0ration number: PROSPERO CRD42020199392. FUNDING Coordination for the Improvement of Higher Educational Personnel (CAPES, Process code-001).
Collapse
Affiliation(s)
| | | | | | | | - Guilherme Janson
- Department of Orthodontics, Bauru Dental School, University of São Paulo, Brazil
| | - David Normando
- Department of Orthodontics, Federal University of Pará, Belém, Brazil
| |
Collapse
|
4
|
The rationale for orthodontic retention: piecing together the jigsaw. Br Dent J 2021; 230:739-749. [PMID: 34117429 DOI: 10.1038/s41415-021-3012-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 03/08/2021] [Indexed: 12/12/2022]
Abstract
Retaining teeth in their corrected positions following orthodontic treatment is one of the most challenging aspects of orthodontic practice. Despite much research, the rationale for retention is not entirely clear. Teeth tend to revert to their pre-treatment positions due to periodontal and gingival, soft tissue, occlusal and growth factors. Changes may also follow normal dentofacial ageing and are unpredictable with great variability. In this overview, each of these factors are discussed with their implications for retention, along with adjunctive procedures to minimise relapse. The state of current knowledge, methods used to assess relapse, factors regarded as predictive of or associated with stability as well as overcorrection are outlined. Potential areas requiring further investigation are suggested. The way in which the clinician may manage current retention practice, with a need for individualised retention plans and selective retainer wear, is also considered.
Collapse
|
5
|
Naraghi S, Ganzer N, Bondemark L, Sonesson M. Stability of maxillary anterior teeth after 2 years of retention in adolescents: a randomized controlled trial comparing two bonded and a vacuum-formed retainer. Eur J Orthod 2021; 43:152-158. [PMID: 33351886 DOI: 10.1093/ejo/cjaa077] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Retention of the maxillary anterior teeth is commonly recommended to maintain the teeth in their corrected positions. Both fixed and removable retention methods are used, but the certainty of evidence is low. OBJECTIVE To evaluate post-treatment changes in irregularity of the maxillary six anterior teeth and single tooth contact point discrepancy (CPD) of three different retention methods. TRIAL DESIGN Three-arm parallel group single-centre randomized controlled trial. MATERIALS AND METHODS Ninety patients, 54 girls and 36 boys, were recruited to the study. The inclusion criteria were adolescent patients treated with fixed appliances at least in the maxilla. After gaining informed consent from the patient and their custodians, the patients were randomized to one of three groups: bonded retainer 13-23, bonded retainer 12-22, and removable vacuum-formed retainer (VFR) covering the maxillary teeth including the second molars. The randomization, prepared by an independent person, used blocks of 30. The primary outcomes were changes in single CPD and Little's irregularity index (LII) measured on digitalized three-dimensional study casts before and after 2-year retention. The study casts were anonymized before assessment and the changes were blinded for the assessor. Data were evaluated on an intention-to-treat basis. Thus, all randomized patients were incorporated into the final analysis. RESULTS The LII and CPDs increased slightly in all three groups without any statistically significant differences between the groups. The VFR group showed a small intercanine width increase and some more changes of canine rotations than in the other groups. HARMS No harm was observed in any subjects and none of the patients needed retreatment. LIMITATIONS The trial was a single-centre study and short-term changes were evaluated. CONCLUSIONS All three retention methods showed equally effective retention capacity and all the changes found in the three groups were small and considered clinically insignificant. Thus, the null hypothesis was confirmed. All three methods can be recommended. TRIAL REGISTRATION NCT04616755.
Collapse
Affiliation(s)
- Sasan Naraghi
- Orthodontic Clinic, Public Dental Health, Växjö.,Department of Orthodontics, University of Malmö, Gävle
| | - Niels Ganzer
- Department of Orthodontics, University of Malmö, Gävle.,Orthodontic Clinic, Public Dental Health, Gävle.,Centre for Research and Development, Uppsala University/Region Gävleborg, Gävle, Sweden
| | | | | |
Collapse
|
6
|
Naraghi S, Ganzer N, Bondemark L, Sonesson M. Comparison of post-treatment changes with and without retention in adolescents treated for maxillary impacted canines-a randomized controlled trial. Eur J Orthod 2021; 43:121-127. [PMID: 32133486 PMCID: PMC8023368 DOI: 10.1093/ejo/cjaa010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Objective To evaluate whether retention is needed after orthodontic treatment of impacted maxillary canines. Trial design Two-arm parallel group single-centre randomized controlled trial. Materials and methods Sixty-three patients, 39 girls and 24 boys, were recruited to the study. The inclusion criteria were patients with at least one impacted or unerupted maxillary canine, and moderate irregularity of the maxillary six anterior teeth according to Little’s index (LI). After gaining informed consent from the patient and their custodians, the patients were randomized to one of two groups, i.e. to a non-retention group or a retention group. The randomization process was prepared and carried out by an independent person not involved in the trial and the randomization used blocks of 20 (10 + 10). Primary outcomes were changes in single contact point discrepancy, and LI measured on digitalized three-dimensional study casts 1-year post-treatment. The study casts were anonymized before assessment and the changes were blinded for the assessor. Data were evaluated on an intention-to-treat basis. Thus, all randomized patients were incorporated into the final analysis. In the non-retention group a 10-week interim period was used to detect patients who eventually have a relapse immediately after treatment. If so, the patient got the arch-wire reinserted. Most patients in the retention group received a vacuum-formed retainer and pretreatment spacing cases got a bonded retainer. Results Mean irregularity change was 0.4 mm in the retention and 1.3 mm in the non-retention group (P < 0.001). Maximum change was 2.5 mm in the retention and 3.2 mm in the non-retention group (P < 0.001). Most changes in the non-retention group occurred during the 10-week interim period. In the non-retention group, one patient developed contact point discrepancy of >2 mm during the interim period and was realigned. Harms One patient met the stopping guideline criteria. This patient had the arch wire reinserted for 2 months. After realignment, the patient received a retention appliance. Limitations The trial was a single-centre study and short-term changes were evaluated. Conclusions Changes between the retention and the non-retention group were statistically but not clinically significant. Since satisfactory clinical results 1-year post-treatment were found in the non-retention group, retention does not appear to be needed. The 10-week interim period was useful in detecting patients who might have a relapse immediately after treatment. Trial registration The trial was not registered.
Collapse
Affiliation(s)
- Sasan Naraghi
- Orthodontic Clinic, National Health Service, Växjö, Sweden.,Department of Orthodontics, University of Malmö, Sweden
| | - Niels Ganzer
- Department of Orthodontics, University of Malmö, Sweden.,Orthodontic Clinic, Public Dental Health, Gävle, Sweden.,Centre for Research and Development Uppsala University/Region Gävleborg, Gävle, Sweden
| | | | | |
Collapse
|
7
|
Bjering R, Vandevska-Radunovic V. Occlusal changes during a 10-year posttreatment period and the effect of fixed retention on anterior tooth alignment. Am J Orthod Dentofacial Orthop 2018; 154:487-494. [DOI: 10.1016/j.ajodo.2017.12.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 12/01/2017] [Accepted: 12/01/2017] [Indexed: 10/28/2022]
|
8
|
Changes of bite force and occlusal contacts in the retention phase of orthodontic treatment: A controlled clinical trial. Am J Orthod Dentofacial Orthop 2017; 152:767-777. [PMID: 29173856 DOI: 10.1016/j.ajodo.2017.03.028] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 03/01/2017] [Accepted: 03/01/2017] [Indexed: 11/22/2022]
|
9
|
Stability of anterior tooth alignment 10 years out of retention. J Orofac Orthop 2017; 78:275-283. [DOI: 10.1007/s00056-017-0084-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 01/04/2017] [Indexed: 12/01/2022]
|
10
|
de Bernabé PGG, Montiel-Company JM, Paredes-Gallardo V, Gandía-Franco JL, Bellot-Arcís C. Orthodontic treatment stability predictors: A retrospective longitudinal study. Angle Orthod 2016; 87:223-229. [PMID: 27598905 DOI: 10.2319/053116-435.1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE To examine medium- to long-term orthodontic treatment stability and its possible association with certain variables. MATERIALS AND METHODS In a retrospective longitudinal study of 70 postretention patients, the Peer Assessment Rating (PAR) index was measured at the start (T1) and end (T2) of treatment and between 4 and 10 years afterwards (T3). The stability was considered absolute when the T2 and T3 values were identical and relative when the difference was within the ±5 range. RESULTS Among the 70 patients, 65.8% were female and 34.2% were male. Their mean age was 14.5 years. The mean treatment length was 2.4 years. The mean retention phase was 3.3 years. The mean pre- and posttreatment PAR scores were 29.8 (T1) and 6.3 (T2). The mean T1-T2 difference was 23.6. The mean T2-T3 difference was -0.39. CONCLUSIONS Within the study, 7.1% presented absolute stability and 68.6% presented relative stability. Lower anterior segment alignment and overbite were the most unstable occlusal features and tended to worsen. Fixed retainer (odds ratio [OR] 0.31; 95% confidence interval [CI] 0.10-0.98) as a protective factor and years without retention (OR 1.32; 95% CI 1.03-1.68) as a risk factor are predictor variables of instability in the case of lower anterior segment alignment. The PAR value at the end of treatment (OR 1.29; 95% CI 1.08-1.54) and extractions (OR 4.76; 95% CI 1.05-21.6) before treatment are predictors for midline instability.
Collapse
|
11
|
Al-Moghrabi D, Pandis N, Fleming PS. The effects of fixed and removable orthodontic retainers: a systematic review. Prog Orthod 2016; 17:24. [PMID: 27459974 PMCID: PMC4961661 DOI: 10.1186/s40510-016-0137-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Accepted: 06/30/2016] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVE In the view of the widespread acceptance of indefinite retention, it is important to determine the effects of fixed and removable orthodontic retainers on periodontal health, survival and failure rates of retainers, cost-effectiveness, and impact of orthodontic retainers on patient-reported outcomes. METHODS A comprehensive literature search was undertaken based on a defined electronic and gray literature search strategy ( PROSPERO CRD42015029169). The following databases were searched (up to October 2015); MEDLINE via OVID, PubMed, the Cochrane Central Register of Controlled Trials, LILACS, BBO, ClinicalTrials.gov, the National Research Register, and ProQuest Dissertation and Thesis database. Randomized and non-randomized controlled clinical trials, prospective cohort studies, and case series (minimum sample size of 20) with minimum follow-up periods of 6 months reporting periodontal health, survival and failure rates of retainers, cost-effectiveness, and impact of orthodontic retainers on patient-reported outcomes were identified. The Cochrane Collaboration's Risk of Bias tool and Newcastle-Ottawa Scale were used to assess the quality of included trials. RESULTS Twenty-four studies were identified, 18 randomized controlled trials and 6 prospective cohort studies. Of these, only 16 were deemed to be of high quality. Meta-analysis was unfeasible due to considerable clinical heterogeneity and variations in outcome measures. The mean failure risk for mandibular stainless steel fixed retainers bonded from canine to canine was 0.29 (95 % confidence interval [CI] 0.26, 0.33) and for those bonded to canines only was 0.25 (95 % CI: 0.16, 0.33). A meta-regression suggested that failure of fixed stainless steel mandibular retainers was not directly related to the period elapsed since placement (P = 0.938). CONCLUSION Further well-designed prospective studies are needed to elucidate the benefits and potential harms associated with orthodontic retainers.
Collapse
Affiliation(s)
- Dalya Al-Moghrabi
- Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, E1 2AD, UK.
| | - Nikolaos Pandis
- Dental School, Medical Faculty, University of Bern, Bern, Switzerland
| | - Padhraig S Fleming
- Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, E1 2AD, UK
| |
Collapse
|
12
|
Bjering R, Birkeland K, Vandevska-Radunovic V. Anterior tooth alignment: A comparison of orthodontic retention regimens 5 years posttreatment. Angle Orthod 2015; 85:353-359. [PMID: 25140669 PMCID: PMC8612417 DOI: 10.2319/051414-349.1] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 06/01/2014] [Indexed: 01/13/2024] Open
Abstract
OBJECTIVE To assess orthodontic treatment outcome at debonding and at 3 and 5 years after orthodontic treatment and to investigate the influence of different retention protocols on anterior tooth alignment. MATERIALS AND METHODS Using the Peer Assessment Rating (PAR) Index, 169 patients (74 boys, 95 girls) were analyzed at four stages: pretreatment (T0), posttreatment (T1), 3 years posttreatment (T3), and 5 years posttreatment (T5). The PAR anterior component scores (ACSs) were compared between groups with different retention protocols. In the maxilla, protocols were removable retainer until T3 (MAX1), removable and fixed retainer until T3 (MAX2), and removable retainer until T3 and fixed retainer until T5 (MAX3). In the mandible, protocols were no retainer (MAND1), fixed 3-3 retainer until T3 (MAND2), and fixed 3-3 retainer until T5 (MAND3). RESULTS Mean weighted improvement in PAR score was 88.3% at T1, 86.4% at T3, and 82.1% at T5. The ACS for the maxilla showed no significant differences between the retention protocols at any time point. In the mandible, the group without retention showed a gradual but not significant deterioration in ACS throughout the posttreatment period. At T5 there was a significant difference in ACS between the group that had the retainer removed at T3 and the group that kept the retainer. CONCLUSION The 5-year treatment outcome, as measured by the PAR Index, was good. Stability of the maxillary anterior alignment 5 years posttreatment did not appear to be influenced by choice of retention protocol. Mandibular anterior alignment was significantly better for the group using a fixed retainer compared with the group where the retainer was removed 3 years posttreatment.
Collapse
Affiliation(s)
- Ragnar Bjering
- PhD student, Department of Orthodontics, Faculty of Dentistry, University of Oslo, Norway
| | - Kari Birkeland
- Associate Professor, Department of Orthodontics, Faculty of Dentistry, University of Oslo, Norway
| | | |
Collapse
|