Development of a Clinical Practice Guideline for Orthodontic Retention PDF

Received: 27 November 2018 | Revised: 31 January 2019 | Accepted: 2 February 2019 DOI: 10.1111/ocr.12302 REVIEW ARTICLE Development of a clinical practice guideline for orthodontic retention Cleo Wouters1 | Toon A. Lamberts2 | Anne Marie Kuijpers-Jagtman1...

Received: 27 November 2018 | Revised: 31 January 2019 | Accepted: 2 February 2019 DOI: 10.1111/ocr.12302 REVIEW ARTICLE Development of a clinical practice guideline for orthodontic retention Cleo Wouters1 | Toon A. Lamberts2 | Anne Marie Kuijpers-Jagtman1 | Anne Marie Renkema1 1 Department of Dentistry, Section of Orthodontics and Craniofacial Structured Abstract Biology, Radboud University Medical Center, Objectives: To develop a clinical practice guideline (CPG) for orthodontic retention Nijmegen, The Netherlands 2 (OR). Knowledge Institute of the Federation of Medical Specialists, Utrecht, The Materials and Methods: The CPG was developed according to the AGREE II instru- Netherlands ment and EBRO (Dutch methodology for evidence-­based guideline development). Correspondence Reporting was done according the RIGHT statement. A Task Force developed clinical Cleo Wouters, Department of Dentistry, questions regarding OR. To answer these questions, a systematic literature search in Section of Orthodontics and Craniofacial Biology, Radboud University Medical PubMed and EMBASE was performed. Two independent researchers identified and Centre, Nijmegen, The Netherlands. selected studies, assessed risk of bias using Cochrane RoB tool and rated quality of Email: [email protected] evidence using GRADE. The Task Force formulated considerations and recommenda- tions after discussing the evidence. The concept CPG was sent for commentary to all relevant stakeholders. Result: One systematic review—with 15 studies—met the inclusion criteria. In case of low evidence and lack of outcome measures, expert-­based considerations were de- veloped. Over four meetings, the Task Force reached consensus on considerations and recommendations, after which the concept CPG was ready for the commentary phase. After processing the comments, the CPG was presented to the Dutch Association of Orthodontists, whereafter authorization followed. Limitations: The paucity of evidence-­based studies concerning OR and the reporting of measurable patient outcomes. Conclusion: This CPG offers practitioner recommendations for best practice regard- ing OR, may reduce variation between practices and assists with patient aftercare. A carefully chosen retention procedure for individual patients, combined with clear in- formation and communication between orthodontist, dentist and patient will con- tribute to long-­term maintenance of orthodontic treatment results. KEYWORDS clinical practice guideline, orthodontic, retention This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. © 2019 The Authors. Orthodontics & Craniofacial Research Published by John Wiley & Sons Ltd Orthod Craniofac Res. 2019;22:69–80. wileyonlinelibrary.com/journal/ocr | 69 70 | WOUTERS et al. 1 | I NTRO D U C TI O N practices with great interest and expertise in OR. They were all trained at different universities and geographically spread over Orthodontic treatment is successful when the treatment goal is the country. For methodological support, an expert in CPG de- achieved, and the result remains stable. Unfortunately, teeth tend to velopment from the Knowledge Institute of Medical Specialists, migrate to their initial position—known as relapse.1 Furthermore, due Utrecht, The Netherlands, was involved. The patients’ Federation to post-­pubertal growth and ageing, changes occur in all individuals, (patients’ association), although invited to participate in the Task with and without orthodontic treatment. 2,3 To maintain treatment Force as a representative of laymen, decided only to be involved in results and to prevent dental changes after treatment, orthodontic the commentary phase. retention (OR) is utilized in virtually every patient.4,5 Different re- Development and writing of the CPG took place from September tention procedures are in use; however, there is no agreement upon 2015 to July 2018. which retention regimen should be recommended. Retention can be implemented with removable and fixed retain- 2.2 | Guideline development ers. Differences may exist in design, material and duration. Common removable retainers are Hawley-­t ype retainers (HRs) and vacuum-­ The CPG for OR was developed according to the AGREE II instru- formed retainers (VFRs). Fixed retainers are usually bonded to (a) ment (Appraisal of Guidelines for Research & Evaluation II) and all anterior teeth, (b) only upper incisors or (c) only lower canines. EBRO (Evidence-Based Richtlijnontwikkeling, the Dutch Method for Especially in the upper arch, a combination of removable and fixed Evidence-­Based Guideline Development) and the reporting fol- retainers is often used. Consideration must be given to potential lows the RIGHT statement (Reporting Items for practice Guidelines changes in tooth position, as well as the willingness and ability of in Healthcare).9,10 Steps for developing the CPG were preparation the patient to cooperate with the retention procedure. The choice phase, development phase, commentary phase and authorization for a certain retention procedure appears to be mainly experience phase. based.6 During the preparation phase, relevant topics were translated Various surveys carried out worldwide show some agreement into clinical questions (CQs). This was achieved by consultation of in the application of retention procedures; however, large individual the Task Force and research into OR procedures.5 All NVvO mem- 5 differences exist. To diminish practice variation, it is meaningful to bers were given the opportunity to give feedback on the CQs before develop a clinical practice guideline (CPG) for OR, for which a de- the literature search was performed. mand has been demonstrated.7,8 Therefore, the aim of this study was to develop a CPG according 2.3 | Literature search to a strict scientific protocol, including clinical considerations and recommendations on OR. This CPG is primarily intended for clinical In the development phase, a systematic literature search—based decision-­making for orthodontists and applies to individuals of any on the CQs—was performed in cooperation with a senior librarian age after orthodontic treatment. Secondly, this study is intended for specialized in health sciences (Supporting information). PubMed and dentists and orthodontic patients. The CPG does not apply to pa- EMBASE were searched until 26 January 2016. Two members of tients with cleft lip and palate or other craniofacial deformities. the Task Force (AMR and CW) assessed the literature search twice and independently, following predetermined inclusion and exclusion criteria (Table 1). The analysis was limited to randomized controlled 2 | M ATE R I A L S A N D M E TH O DS trials (RCTs), and systematic reviews (SRs) were written in English and Dutch. 2.1 | Initiative and task force Initial screening for eligibility was based on title and abstract and In 2015, the Dutch Association of Orthodontists (NVvO, was done separately for all CQs. The selected articles were screened Nederlandse Vereniging van Orthodontisten) initiated the develop- based on full text. Differences between observers were discussed ment of a CPG for OR. A Task Force was convened, consisting of and solved by consensus. Articles that complied with the inclusion five members of the NVvO as representatives of the professional and exclusion criteria were then used to answer the CQs. group—four orthodontists and one resident in orthodontics. The Study characteristics of the selected articles were clearly pre- orthodontists were clinicians working in academia or in private sented in evidence tables. If possible, a meta-­analysis was performed TA B L E 1 Inclusion and exclusion Inclusion criteria Exclusion criteria criteria Different types of retainers Bonding procedures Papers concerning efficacy Prosthetic retainers Papers concerning safety Retention combined with fiberotomy Complications Retention after removable orthodontic treatment Patient perception of retainers Surgical interventions Cleft lip and palate, craniofacial anomalies WOUTERS et al. | 71 by pooling data across studies. Additionally, a hand search was per- After comments were considered and processed, an implementation formed on all relevant studies of the search. plan was drafted, and the final CPG was approved by the NVvO and published on their website (www.orthodontist.nl). Moving through all phases of guideline development took 3 years. 2.4 | Assessment of quality of evidence Two independent researchers (AMR and CW) assessed risk of bias 3 | R E S U LT S using the Cochrane RoB tool and rated the quality of evidence using GRADE (Grading Recommendations Assessment, Development and 3.1 | Literature search Evaluation). Limitations in study design, inconsistency, indirectness, imprecision and publication bias were examined. Quality of evidence Based on the initial consultation of the Task Force and research into was rated—high, moderate, low and very low—for each outcome OR procedures, three CQs were formulated by the Task Force. They measure and reflects the degree of certainty that exists over the considered stability, failure, adverse effects and patient satisfac- literature results.11 tion as critical outcome measures for decision-­making (Table 2). The search strategy for CQ1 yielded 723 studies in MEDLINE and 592 in EMBASE (Supporting information), of which 464 were duplicates. 2.5 | Recommendations After screening according to title and abstract, 536 studies were ex- During the Task Force meetings, evidence was discussed, and con- cluded because they did not meet the inclusion criteria (no RCTs or siderations were drafted to enable the development of recommen- SRs). Full-­text screening of the remaining 315 eligible studies identi- dations. Other factors including patients’ preferences, values and fied four SRs, of which one with 15 studies met the inclusion criteria compliance, risks, side effects and organizational matters were also (Figure 1).12 considered. Therefore, recommendations were based on available Regarding CQ1 comparison a, no studies were found suitable for evidence combined with considerations based on additional litera- analysis. Regarding CQ1 comparison b, c and d, the included RCTs ture and expert opinion. are listed in Table 3. To answer CQ2 and CQ3, a hand search was The strength—strong, weak—of recommendations was depen- performed on all relevant studies of the search. dent on the quality of evidence, the consensus considerations and the importance the Task Force assigned to the various aspects and argu- 3.2 | Literature analysis and quality of evidence ments. According to the GRADE methodology, it is possible to draw strong recommendations with low levels of evidence, and vice versa. Risk of Bias tables for the included SR are found in Supporting in- Based on the recommendations, an implementation plan was written. formation. If possible, each outcome of a CQ comparison was rated according to GRADE before literature conclusions and recommen- dations were drafted. 2.6 | Commentary phase, authorization phase and Reported evidence in the literature and the quality of evidence implementation for the clinical questions are described in Table 3. In this table, the A draft version of the CPG was sent to all members of the NVvO and evidence for each specific outcome is enumerated and the GRADE other relevant stakeholders (Supporting information) for an exter- level (“Quality of evidence”) indicated. In general, the quality of the nal review, giving them the opportunity to comment within 7 weeks. available evidence was rated as low or very low and patient-­reported TA B L E 2 Clinical questions CQ 1 Which retainer is best for retaining the upper and lower arch after orthodontic treatment? Fixed versus removable retainers upper arch (a) Fixed versus removable retainers lower arch (b) Design and wire material upper fixed retainers (c) Design and wire material lower fixed retainers (d) Removable retainers for upper and lower arch (e) Outcome measures Stability: Little’s Irregularity Index, settling of the occlusion, intercuspid distance and molar distance, overjet and overbite Failure probability: bond failure, broken or lost retainers Adverse effects: periodontal bleeding, pockets and caries Survival time Patient’s satisfaction CQ 2 Which frequency of retention check-­ups is advisable for different forms of retention? CQ 3 What are the responsibilities of the orthodontist, dentist and patient to provide successful OR? 72 | WOUTERS et al. Records identified through database Records identified through database Identification searching MEDLINE (OVID) searching EMBASE (n = 723) (n = 592) Records after duplicates removed (n = 851) Records excluded (n = 536) Screening Records screened (n = 315) Full-text articles excluded, with reasons (n = 311) Full-text articles assessed for eligibility (n = 4) Eligibility Studies included in qualitative synthesis (n = 1) Included Studies included in quantitative synthesis F I G U R E 1 PRISMA flow chart [Colour (meta-analysis) (n = 1) figure can be viewed at wileyonlinelibrary. com] outcome measures were virtually lacking. In case of low evidence 4 | D I S CU S S I O N and lack of outcome measures, the Task Force developed consid- erations and recommendations based on their interpretation of the The aim of this CPG was to develop evidence-­based, and if neces- literature, clinical experience and discussions held during the con- sary, consensus-­based, recommendations for OR. The discussion sensus meetings. includes the considerations of the Task Force on available evidence, using relevant studies found during the hand search. The discussion is subdivided based on the clinical questions. Final recommendations 3.3 | Final recommendations follow after the discussion and are developed using both evidence Recommendations were drafted for each CQ, based on the literature and considerations. conclusions, expert considerations, clinical experience and discus- During a Task Force meeting, it was considered that prior to or- sions held during the consensus meetings. In four meetings, the Task thodontic treatment, the retention modality for the upper and lower Force reached consensus on the final recommendations, after which arch—with advantages and disadvantages—must be discussed with the conceptualized CPG was ready for the commentary phase. the patient and caretaker. 3.4 | Commentary phase, authorization phase and 4.1 | CQ1a Which retainer is best for retaining the Implementation upper arch? The Task Force received 125 comments of six stakeholders. The Based on Littlewood et al. (2016), no clear evidence exists which comments were reviewed and processed during a meeting of the retention modality is preferred for the upper arch.12 A recent pub- Task Force. In July 2018, the final guideline was presented to the lication provides an answer to the question, but the results must NVvO, whereafter formal authorization followed in September be interpreted with caution; according to Forde et al. (2018), upper 2018. The implementation plan states that strong recommendations arch alignment remains equally stable with removable and fixed should be implemented within 1 year after publication of the CPG retainers.13 and others within 3 years after authorization. The CPG will be re-­ For retention of the upper arch, Dutch orthodontists apply a evaluated within 5 years and—if indicated—updated every 5 years. combination of (a) a fixed and removable retainer, (b) a solitary fixed WOUTERS et al. | 73 TA B L E 3 Literature conclusions and quality of evidence Quality of evidence References Outcome Literature conclusion GRADE first author year CQ1b Stability Orthodontic treatment results in the lower arch are best retained with fixed Low Millet (2007)76 retainers. Survival Conflicting results are reported regarding failure rates among lower fixed and Very low Artun (1997)78 removable retainers. Millett (2007)75 Adverse More gingivitis and periodontal pockets are found with the use of fixed mandibular Low Millett (2007)77 effects retainers, than with removable retainers. Patient Patients accept removable vacuum-­formed retainers better than fixed retainers. Low Millett (2007)75 satisfac- Patient satisfaction is similar for fixed and removable retainers. Low Millett (2007)75 tion CQ1c Survival On the long-­term base, no differences are found between the number of bond Low Bolla (2012)79, Salehi failures of glass fibre reinforced fixed retainers and multi-­strand fixed retainers. (2013)22 CQ1d Survival Retainers made of thick, twisted multi-­strand wires or single-­strand wires—only Low Artun (1997)78 bonded to the canines—and retainers made of thin multi-­strand wires—bonded to all anterior teeth—do have a similar failure rate. Glass fibre reinforced fixed retainers and thin multi-­strand fixed retainers do have a Low Bolla (2012)79, Rose comparable failure rate. (2002) 80, Salehi (2013)22 CQ1e Stability Little’s Irregularity Index Six months post-­treatment, Little’s Irregularity Index is equal after full-­time and Low Gill (2007)56 part-­time wear of thermoplastic retainers. Derotated teeth are better retained with thermoplastic retainers (9-­month Moderate Rohaya (2006) 81 part-­time) than with Hawley retainers (3-­month full-­time, 6-­month part-­time). Three-­month full-­time wear of Hawley retainers, followed by 3-­month part-­time Low Rowland (2007) 47 wear is superior to full-­time wear of thermoplastic retainers for 1 week followed by part-­time wear for 6 months. One year post-­treatment, Little’s Irregularity Index is equal after full-­time and Low Shawesh (2010)57 part-­time wear of Hawley retainers. Settling of the occlusion Six months post-­treatment, the number of occlusal contacts is equal after full-­time Very low Aslan (2013)65 wear of modified thermoplastic retainers and full-­coverage thermoplastic retainers. An extra three-­month part-­time wear of modified thermoplastic retainers and Very low Aslan (2013)65 full-­coverage thermoplastic retainers, results in more posterior occlusal contacts with modified thermoplastic retainers. Intermolar and intercuspid distance Six months post-­treatment, intermolar and intercanine distances are equal after Low Gill (2007)56 full-­time and part-­time wear of thermoplastic retainers. Intermolar distances are, after a 3-­month full-­time wear of Hawley retainers Low Rowland (2007) 47 followed by a 3-­month part-­time wear, comparable with intermolar distances after 1-­week full-­time wear of thermoplastic retainers followed by 6-­month part-­time wear. Overjet and overbite Six months post-­treatment, overjet and overbite are comparable after full-­time and Low Gill (2007)56 part-­time wear of thermoplastic retainers. (Continues) 74 | WOUTERS et al. TA B L E 3 (Continued) Quality of evidence References Outcome Literature conclusion GRADE first author year Survival Six months post-­treatment, the failure rate is higher for Hawley retainers than for Moderate Rowland (2007) 47 thermoplastic retainers. One year post-­treatment, the failure rate for Hawley-­ and thermoplastic retainers is Low Sun (2011) 82 equal. Patient Six months after treatment, compliance and acceptance (aesthetics and comfort) of Low Rowland (2007) 47 satisfac- thermoplastic retainers is better than compliance and acceptance of Hawley tion retainers. retainer or (c) a solitary removable retainer in respectively 54%, 34% In comparison with removable retainers, lower fixed retainers and 1% of their cases.5 Dual upper retention—a fixed retainer com- lead to more gingival bleeding, pockets and recessions. 20,25 The bined with a removable retainer worn nightly—is recommended in use of lower removable retainers is preferable in cases with poor high-­risk cases.14,15 It prevents dental changes in case of bond fail- oral hygiene.7 However, since VFRs are contraindicated in patients ures and gives the patient extra time for repair. It also prevents tooth with poor oral hygiene, HRs are indicated in these cases.4 An alter- movement, deleterious effects on the periodontium caused by un- native choice is a retainer only bonded to the lower canines.7 For intentionally active retainers and holds the transverse dimension if the patient and dental professional, the cleaning of this retainer needed.16 type is easier. 26 Patients should, however, be informed about the The choice for the upper retention modality is determined by risk of changes in alignment when retainers are only bonded to several factors: initial malocclusion, treatment result, treatment mo- the lower canines. When oral hygiene is sufficient, lower fixed re- dality, oral hygiene, patients’ compliance, personal preferences and tention should be the first choice. 27 Dual lower retention—a fixed 6,7 practitioners’ experience. retainer combined with a removable retainer worn nightly—is rec- Advantages and disadvantages of removable and fixed retain- ommended for high-­risk cases, as is previously mentioned for the ers can also determine the choice. Removable retainers are easy to upper arch.15 clean, but compliance is difficult, even when the retainer only has to be worn at night.13,17,18 If not worn as prescribed, relapse may 4.3 | CQ1c Which design and wire material are best occur.19 Oral hygiene with fixed retainers needs to be perfect, while for upper fixed retainers? patients find them difficult to clean.13,16,20 The use of upper remov- able retainers is preferred in cases with a low risk of relapse, poor Based on Littlewood et al. (2016), no clear evidence exists in deter- oral hygiene, and after extractions and expansion.6–8 However, since mining which fixed retainer design and material is preferable for re- VFRs are contraindicated in patients with high plaque levels, HRs are tention of the upper arch.12 indicated in those cases.4 Upper fixed retainers usually include either all six anterior teeth Oral habits, including chewing on pens, nail biting and the open- or only all four incisors.5 When all anterior teeth are bonded, more ing of sports bottles, may compromise the enamel-­composite in- failures/fractures are observed, probably due to contact of the terface, wire-­composite interface or the retainer wire, resulting in lower canines with the wire. 28 According to Steinnes et al. (2017), breakage, bond failures and unintentionally active retainers causing alignment is eight years post-­treatment stable when the retainer 5,21,22 unwanted tooth movements. wire is only bonded to the upper incisors. 29 Not only the design but also the material for bonded retain- ers is important. Overall, stainless-­s teel (SS) wires, either multi-­ 4.2 | CQ1b Which retainer is best for retaining the strand or single strand, and reinforced glass fibres are used in lower arch? modern clinical practice. Our literature results regarding glass Based on Littlewood et al. (2016), no clear evidence exists concern- fibre reinforced fixed retainers contradict findings in more recent ing which retention modality is preferable for the lower arch.12 The studies. 30,31 Although aesthetic in appearance, compared with SS more recent publications of Westerlund et al. (2015), O'Rourke et al. wires, they are susceptible to a higher risk of failure. This is be- (2016) and Forde et al. (2018) conclude that lower arch alignment cause they break easily and have higher failure rates due to con- is more effectively retained with fixed rather than with removable tamination during bonding. 31 13,23,24 retainers. The increase in Little's Irregularity Index with re- The mobility of teeth connected to a retainer wire is depen- movable retainers is most likely to be the result of poor compliance. dent on wire material and its cross section.32 Application of single-­ Therefore, the Task Force recommended retention with fixed retain- strand SS wires will result in lower tooth mobility compared to the ers in the lower arch. use of multi-­strand SS wires with identical design and cross section, WOUTERS et al. | 75 resulting in a higher risk of bond failures. Torque resistance of single-­ 4.5 | CQ1e Which type of removable retainer is best strand 0.016 × 0.016-­inch SS wires and multi-­strand 0.016 × 0.022-­ for retaining the upper and lower arch? inch SS is much higher than torque resistance of round 6-­stranded co-­axial SS and 3-­stranded twisted SS wires. Therefore, the former Based on Littlewood et al. (2016), no clear evidence exists to deter- wires are preferred for retention of the upper arch.33 mine which removable retainer is best for retaining the upper and Stiffness of dead-­soft—annealed—wires is reduced, resulting in lower arch.12 In general, HRs and VFRs are used and the stability 33 an increased yield strength. The advantage of dead-­soft wires is of these appears to be comparable. If irregularities arise, they are their ease to adjust and insert. The disadvantage of dead-­soft wires usually not clinically relevant.46–51 These findings suggest that fac- 34–36 is their high risk of fracture and decreased retention capacity. tors other than stability are important in the choice of removable Bonded retainers can become unintentionally active due to retainers. the properties of the wire material, elastic deflection during inser- Patients prefer VFRs over HRs because they are more comfort- tion and repair, mechanical deflection caused by chewing forces able.52,53 According to Wan et al. (2016), this is due to the negative and parafunctions. 33,35,37–42 Although the incidence of this phe- impact of HRs on speech.54 nomenon is low, it is highly problematic, since the consequences Results of studies into failure rates of HRs and VFRs show con- can be dramatic if unnoticed. 39–41 The use of rectangular and flicting results. According to our results, HRs fail more often than square wires will decrease the incidence of unintentionally active VFRs. Pratt et al. (2011) compared both retainers one year post-­ retainers. 5,33 treatment and found that VFRs fail more often. 55 Their explanation was that functional and parafunctional activities can lead to break- age. This phenomenon is particularly observed in grinders. 4.4 | CQ1d Which design and wire material are best To date, research into the cost-­effectiveness of various retention for lower fixed retainers? procedures and in patient satisfaction has received little attention. Based on Littlewood et al. (2016), no clear evidence exists concern- VFRs are more cost effective than HRs.52,53 These factors should be ing which fixed retainer design and wire material is preferable for further investigated. retention of the lower arch.12 The choice of a fixed retainer design According to our results, the full-­t ime or part-­t ime wearing of and wire material for retention of the lower arch is determined by removable retainers is comparable in stability. This finding is sup- the same factors as those for fixed retainers in the upper arch (see ported in other studies. 56–59 However, during the first weeks di- CQ1c). rectly after active treatment teeth are more prone to relapse. 60,61 Lower fixed retainers usually include either all six anterior teeth When removable retainers are worn part time during this period, or are fixed to the canines only.5 Our literature results regarding teeth will experience jiggling which is unpleasant for the pa- stability and failure rates with both retainer designs contradict tient. 62–64 Therefore, the wearing of removable retainers full time with findings from more recent studies. When all anterior teeth are for a short period of time could be recommended, especially in bonded, the lower front region is better stabilized; however, more patients with a high risk of relapse.4 When removable retainers 38,43 failures are observed. are combined with fixed retainers, less jiggling will be experienced From clinical experience, it is known that today's patients are and part-­t ime wear of a removable retainer will be sufficient from more demanding, and their dental awareness has increased. Even the very beginning. small positional changes are no longer accepted. This has led to an When comparing the different retention procedures with remov- increase in the use of lower retainers bonded to all anterior teeth able retainers, all seemed to be equally effective in stabilizing the instead of lower retainers only bonded to the canines.5 treatment result on a short-­term basis. However, strong evidence, Although the failure rate of lower retainers bonded to all anterior regarding differences in stability between part-­time retention with teeth is higher than of retainers only bonded to the canines, prefer- HRs and VFRs, was lacking. ence is given to the retainer that seems to provide better stability.38 The advantage of HRs is that teeth have the ability to settle, In high-­risk patients with extreme rotations and spacing in the ante- leading to more occlusal contacts and a better interdigitation. This is rior region prior to orthodontic treatment, the first choice in retainer difficult to achieve with a full-­coverage VFR.65 should be a retainer bonded to all lower anterior teeth. However, in cases of poor oral hygiene the use of a wire only 4.6 | CQ2 Which frequency of retention check-­ups bonded to the canines should be considered.7 In comparison with is advisable for different forms of retention? a wire bonded to all lower front teeth, a wire only bonded to the canines is easier to clean for both the patient and the dental Despite the use of retention, dental changes can occur after treat- professional. 26 ment. The periodontal fibres reorganize, forces act on the dentition When the wire is only bonded to the canines, rather than using due to orofacial muscles and occlusal contacts, post-­pubertal crani- a tick twisted multi-­strand SS wire, a thick single-­strand SS wire ofacial growth occurs, as does ageing. 2,3,66 Additionally, the com- should be used. This is because a thick single-­strand wire is more pliance of the patient in wearing removable retainers and the side comfortable for the tongue and less plaque sensitive.44,45 effects of fixed retainers make it necessary to plan check-­ups after 76 | WOUTERS et al. treatment. The included systematic review did not pay attention to accordingly, and the dentist has to deal with information provided 12 the frequency of retention check-­ups. An alternative literature by the orthodontist in a professional manner. Responsibility for the search showed a lack of available literature on this topic. The number retention phase lies within the combination of orthodontist-­patient-­ of retention check-­ups varies a lot in number and duration.5–8,55,67,68 dentist. A joint responsibility for the retention phase can only be Schneider et al. (2011) and others showed that failure of fixed re- achieved with clear information.72 tainers is highest directly after the debonding of orthodontics ap- pliances. 28,69,70 The combination of increased mobility together with 5 | K E Y R ECO M M E N DATI O N S increased failure risk within the first month after debonding indi- cates the first retention check-­up should occur within the first three 5.1 | CQ1a Retention in the upper arch months post-­treatment. Additionally, the wearing of removable retainers can also be checked. When retention check-­ups are fre- Apply removable upper retainers in patients with a low risk of quently performed, the compliance of the patient can be positively relapse. influenced.46,71 When no problems exist during the first retention Apply fixed upper retainers in patients with a moderate risk of check-­up, a longer period until the next check-­up can be advised. relapse. Two to three retention check-­ups should be planned within the first Apply dual upper retention in patients with a high risk of relapse. year after treatment. Following this, an annual retention check-­up Consider the use of upper HRs in patients with poor oral hygiene. is advised. 5,55 However, the increase in the number of patients to- gether with the tendency towards permanent retention leads to an 5.2 | CQ1b Retention in the lower arch increase in work load.5,8 Therefore, the Task Force considered to refer patients to their dentist for further retention check-­ups which Apply fixed retainers for lower arch retention. can be performed simultaneously with the annual dental check-­up. Apply dual lower retention in patients with high risk of relapse. Consider the use of lower HRs in patients with poor oral hygiene. 4.7 | CQ3 What are the responsibilities of the orthodontist, dentist and patient to provide 5.3 | CQ1c Design and wire material for upper successful OR? fixed retainers Most orthodontists use permanent retention, and therefore, it is Bond all upper six anterior teeth in case of initial rotations. crucial to check retainers on a regular basis to examine their func- Use square or rectangular SS wire material for upper fixed tion and the health of surrounding tissues. 8,37,42 retainers. Clear communication between the orthodontist and dentist Consider the use of lateral-to-lateral fixed upper retainers in case about all aspects of OR is necessary in order to transfer the respon- of dual retention. sibility to the dentist. 26 It is not only important to request the dentist take over aftercare, but also necessary for agreements to be made 5.4 | CQ1d Design and wire material for lower between the orthodontist and dentist about repair and replacement fixed retainers of retainers. The dentist should be aware that despite the presence of retainers, changes in the position of the teeth and unwanted side Bond retainers to all lower six anterior teeth in patients with a effects may occur.4 The role of the dentist in OR is of great impor- high risk of relapse. tance in terms of (a) motivating patients to take care of their retain- Use square or rectangular SS wire material for lower fixed retainers. ers and be compliant, (b) assessing whether the treatment result is Consider the use of retainers only bonded to the lower canines in stable, oral hygiene is appropriate and retainers are intact, (c) repair- patients with a low risk of relapse. ing or replacing retainers if necessary and (d) consulting the ortho- Consider the use of thick single-strand SS retainers only bonded dontist if necessary.14 to the lower canines in patients with poor oral hygiene. The orthodontist must provide patients with clear explanations Inform patients about the risk of changes in alignment when re- of all aspects of OR. The responsibilities of the patient in the re- tainers are only bonded to the lower canines. tention phase should be explained and patients must agree. This in- formation should be in written form.72 It is of great importance to 5.5 | CQ1e Removable retainers inform the patient of the risk of undesirable changes in the position of the teeth.15,73 To minimize this risk, regular retention check-­ups, Choose, based on own experience and patients’ preferences for a initially by the orthodontist and later by the dentist, are necessary. HR retainer or VFR Patient satisfaction with the treatment result is strongly related to Select, when anchorage for a HR is inadequate, a VFR the patient's sense of responsibility for the retention phase. 53 Consider, in case of solitary removable retention and depending It is the responsibility of the orthodontist to provide clear infor- on the initial situation and treatment modality, short-term full- mation on OR, the patient has to accept this information and act time wearing of removable retainers. WOUTERS et al. | 77 A limitation of the development of a CPG is the time period 5.6 | CQ2 Frequency of retention check-­ups needed to work through all phases—in accordance with the AGREE Schedule the first retention check-up preferably within three II instrument, EBRO and the RIGHT statement. The development of months after insertion of the retainers. the CPG for OR took 3 years. It might be contended the guideline Schedule 2-4 retention check-ups in a period of 1-2 years after risks being out of date. However, it is impossible to carry out a new insertion of the retainers, depending on the timing of transferring systematic search during the process. Therefore, in accordance with the patient to the dentist. the AGREE II instrument, the board of the NVvO—as initiator of the Communicate with the dentist regarding retention check-ups to development of a CPG for OR—will regularly review the guideline, guarantee effective retention aftercare. by 2022 at the latest. Should new developments arise that challenge the validity of the guideline, the review process will commence sooner. For the updating procedure, clinical and methodological ex- 5.7 | CQ3 Responsibilities orthodontist, perts will be involved again. dentist, patient Another limitation is the absence of input from laymen during Provide patients with all necessary information regarding their OR the initial process of the guideline development. Their input would Provide dentists with all necessary information regarding the OR perhaps have provided a more patient-­focused guideline. The pa- of their patients tients’ Federation was only involved in the commentary phase and Refer the patient for aftercare to the dentist in a systematic and had no comments. responsible manner Evidence-­based recommendations in a CPG for OR are inter- nationally relevant and therefore directly generalizable to other countries. However, differences in, for example, health insurance 6 | LI M ITATI O N S O F TH E C P G A N D systems, legal obligations as well as cultural differences, may justify S U G G E S TI O N S FO R FU RTH E R R E S E A RC H alternative recommendations within a CPG in different countries.74 As an example, health insurance conditions in the UK (National OR is of great importance for maintaining the result of active or- Health Service) differ from those in the Netherlands. Consequently, thodontic treatment. In order to succeed, the orthodontist must recommendations on OR in the UK may differ from those in the offer the most appropriate retention modality and aftercare for the Netherlands. individual patient, the patient must comply with the rules, and the Littlewood et al. (2016) concluded there is insufficient ev- dentist must provide appropriate aftercare as part of regular dental idence to make recommendations on orthodontic retention check-­ups, and if necessary, refer the patient back to the orthodon- procedures after orthodontic treatment and advised further high-­ tist. Undoubtedly, the success of OR is dependent on the orthodon- quality RCTs are needed.12 However, we have shown that it is fea- tist, patient and dentist working together and on the way in which sible to develop a CPG for retention according to an established each fulfils their duties. “When one of the three drops a stitch, the scientific methodology, since a CPG is not just based on evidence, house of cards collapses.” but also on experience and consensus. With the results of future Significant worldwide documented variability exists in OR pro- well-­d esigned RCTs, it must be possible to enhance the present cedures following active orthodontic treatment, underlining the CPG for retention. Appropriate outcome measures to further in- need for and purpose of the development of a CPG for OR.5,7,8 vestigate include (long-­term) stability, length of retention, survival, During the development of the CPG for OR, it became apparent cost-­effectiveness and adverse effects of retainers, and patient high-­quality evidence relating to the effectiveness, side effects and preference and satisfaction over the long term.12 Also transver- cost-­effectiveness of different retainers and retention modalities to- sal, vertical and sagittal components of malocclusion should then gether with patients’ preference and satisfaction was lacking in the be taken into account. Another important issue, because of the literature. This was especially evident in the reporting of patient out- current propensity for the use of permanent fixed retainers, is to comes. As a result, the strength of the recommendations is predomi- describe and investigate the onset of unintentionally active retain- nantly weak. The development of the CPG for OR is based on studies ers, for the purpose of increasing retainer effectiveness, reducing included in the systematic review undertaken by Littlewood et al. failure rate, increasing patient compliance and limiting the inci- (2016) and a comprehensive review of additional literature.12 From dence of unintentional active retainers. 5 The ultimate goal being reviewing, analysing and evaluating the literature, it was possible to to offer the best retention modality and aftercare for the individ- formally develop consensus among the Task Force in terms of sub- ual patient. stantiating the considerations and recommendations. With regard to CQ2 [Which frequency of retention check-­ups is recommended?] and CQ3 [What are the responsibilities for the orthodontist, patient 7 | CO N C LU S I O N and dentist to provide successful orthodontic retention?], few stud- ies were found in the literature. Therefore, the recommendations The paucity of evidence-­based studies concerning OR leads to a CPG made in answering these CQs are predominately consensus-­based. development mainly based on expert opinion and clinical evidence. 78 | WOUTERS et al. Nevertheless, this CPG provides practitioners with recommenda- 7. Renkema AM, Sips E, Bronkhorst E, et al. A survey on ortho- tions for best practice procedures in OR, may reduce variation dontic retention Procedures in the Netherlands. Eur J Orthod. 2009;31(4):432‐437. between practices and assist with patients’ aftercare. A carefully 8. Lai CS, Grossen JM, Renkema AM, et al. Orthodontic retention pro- chosen retention procedure for the individual patient combined with cedures in Switzerland. Swiss Dent J. 2014;124(6):655‐661. clear information and communication between orthodontist, dentist 9. Brouwers MC, Kho ME, Browman GP, et al. AGREE next steps con- and patient will contribute to the long-­term maintenance of ortho- sortium. AGREE II: advancing guideline development, reporting and evaluation in health care. CMAJ 2010;182(18):e839‐e842. dontic treatment results. 10. Chen Y, Yang K, Marušić A, et al. A reporting tool for practice guide- lines in health care: the RIGHT statement. Annals of Interna Medicin. 2017;166(2):128‐132. AC K N OW L E D G E M E N T S 11. Schünemann H, Brożek J, Guyatt G, et al. GRADE handbook for grading quality of evidence and strength of recommendations. We would like to thank drs. L.H.M. Niesink-­Boerboom Msc., liter- Updated October 2013. The GRADE Working Group, 2013. http:// ature specialist of the Knowledge Institute of Medical Specialists, gdt.guidelinedevelopment.org/central_prod/_design/client/hand- Utrecht, for the systematic literature search. We would also like book/handbook.tml. Accessed October 2013. to thank the members of the Task Force, dr. C.A.M. van Oort-­ 12. Littlewood SJ, Millet DT, Doubleday B, et al. Retention procedures for stabilising tooth position after treatment with orthodontic Bongaarts, drs. A.A.P. Renkema and drs. L. Veldhuijzen-­van Zanten braces (Review). Cochrane Database Syst Rev 2016;(1):CD002283. for their time and effort in completing the CPG. 13. Forde K, Storey M, Littlewood SJ, et al. Bonded versus vacuum-­ formed retainers: a randomized controlled trial. Part 1: stability, re- tainer survival, and patient satisfaction outcomes after 12 months. C O N FL I C T O F I N T E R E S T Eur J Orthod 2018;40(4):387‐398. 14. Johnston CD, Littlewood SJ. Retention in orthodontics. Br Dent J. According to the “Code for the prevention of improper influence 2015;218:119‐122. due to conflicts of interest” (http://www.haring.nl/download/tools/ 15. Littlewood SJ, Kandasamy S, Huang G. Retention and relapse in en/Code_for_the_prevention_of_improper_ influence_due_to_con- clinical practice. Aus Dent J. 2017;62(1):51‐57. flicts_of_interest.pdf) drawn up by a number of Dutch health au- 16. Rody WJ Jr, Wheeler TT. Retention management decisions: a re- view of current evidence and emerging trends. Semin Orthod. thorities, all members of the Task Force were required to disclose 2017;23(2):221‐228. potential conflicts of interest of the last three years regarding fi- 17. Cerny R, Lloyd D. Dentists’ opinions on orthodontic retention appli- nancial (relationship to commercial companies, personal financial in- ances. J Clin Orthod. 2008;42(7):415‐419. terests, research funding) and indirect interests (personal relations, 18. Storey M, Forde K, Littlewood SJ, et al. 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