Removable orthodontic appliances: compliance suboptimal


While the use of fixed functional appliances, implant supported devices and fixed retainers has increased in orthodontics removable appliances still continue to be popular. However, compliance with wearing removable appliance can have a bearing on the success or failure of the treatment.

The main aim of this review was to assess levels of compliance with various removable orthodontic appliances and adjuncts.


Searches were conducted in Medline, Cochrane Central Register of Controlled Trials, Web of Science Core Collection, LILACS, BBO,, National Research Register and Pro-Quest Dissertation and Thesis databases. Quantitative studies including randomised, non-randomised controlled clinical trials, prospective cohort studies, and case series (minimum sample size, 20 patients) incorporating objective data on compliance levels were considered. Qualitative studies exploring patients’ views and experiences of removable orthodontic appliances or adjuncts and the interventions used to improve compliance levels were considered as were mixed methods studies meeting these criteria.

Two reviewers independently selected studies and assessed study quality. The quality of RCTs was assessed using the Cochrane risk of bias tool and the ROBINS-I  tool for non-randomised studies and mixed-methods appraisal tool based on their design. The primary outcome was compliance levels with orthodontic regimens (hours per day of wear or percentage of compliance) in relation to both stipulated and patient-reported levels of wear.


  • 24 studies (2 RCTs, 21 prospective cohorts, 1 mixed-methods study) were included with 11 contributing to the qualitative synthesis.
  • One RCT was at unclear risk of bias the other at high risk.
  • 8 of the cohort studies were considered to be at serious risk of bias.
  • The mean duration of objectively measured wear was considerably lower than stipulated wear time among all appliance types in the included studies.
Type of appliance No. of studies Discrepancy (Hrs/day) 95% confidence interval
Headgear 6 5.81 4.98 to 6.64
Functional appliances 3 5.71 4.98 to 6.45
Maxillary removable 3 3.53 2.06 to 5.00
Hawley retainers 2 4.58 3.21 to 5.95
  • Meta-regression suggested that compliance was not directly related to the type of the appliance.


The authors concluded: –

On the basis of this review, it appears that compliance with removable orthodontic appliances is suboptimal, with patients wearing appliances considerably less than stipulated and routinely over reporting the duration of wear. There is a need for further prospective research evaluating the effectiveness of interventions to improve compliance with orthodontic adjuncts and exploring patient experiences with removable devices and appliances.


The authors have conducted an extensive search for studies to answer this question.  While they identified a reasonable number of studies that demonstrate that patients over report appliance wear they note concern over the quality of the available evidence.  While the evidence is largely from cohort studies this is appropriate, although, they identify that just over a third of these studies suffered from a serious risk of bias.


Primary paper

Al-Moghrabi D, Salazar FC, Pandis N, Fleming PS. Compliance with removable orthodontic appliances and adjuncts: A systematic review and meta-analysis. Am J Orthod Dentofacial Orthop. 2017 Jul;152(1):17-32. doi: 10.1016/j.ajodo.2017.03.019. Review. PubMed PMID: 28651764.

Other references

Original Review Protocol on PROSPERO

Dental Elf – 24th Jul 2014

Few trials on improving adherence amongst orthodontic patients

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Derek Richards

Derek Richards is a specialist in dental public health, Director of the Centre for Evidence-Based Dentistry and Specialist Advisor to the Scottish Dental Clinical Effectiveness Programme (SDCEP) Development Team. A former editor of the Evidence-Based Dentistry Journal and chief blogger for the Dental Elf website until December 2023. Derek has been involved with a wide range of evidence-based initiatives both nationally and internationally since 1994. Derek retired from the NHS in 2019 remaining as a part-time senior lecturer at Dundee Dental School until the end of 2023.

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