, Volume 105, Issue 2, pp 237–247 | Cite as

Performance of clear vacuum-formed thermoplastic retainers depending on retention protocol: a systematic review

  • Eleftherios G. KaklamanosEmail author
  • Maria Kourakou
  • Dimitrios Kloukos
  • Ioannis Doulis
  • Smaragda Kavvadia
Original Article


We aimed at comparing the performance of vacuum-formed thermoplastic retainers (VFR) worn either full-time or part-time, in maintaining orthodontic treatment results in terms of tooth alignment, arch form and occlusion. We reviewed randomized and prospective controlled clinical trials comparing VFR wearing protocols and searched databases, without restrictions, for published and unpublished literature. The risk of bias was assessed using the Cochrane Risk of Bias tool and the overall level of certainty in the evidence following ADA methodology. 184 studies were initially identified and reduced to the 3 randomized controlled trials included in the systematic review by means of specific criteria. One study followed patients 1 year into retention, and the other two for 6 months. Little’s Irregularity Index, intermolar and intercanine width, arch length, overjet and PAR score did not differ significantly between the patients wearing their retainers part time or full time. We observed a slight increase in the overbite in the part-time group in only one trial. With a moderate level of certainty, we found that during the observation period, full-time VFR wear is not superior to part-time, bearing in mind the potential implications for health burden, retainer longevity and cost-effectiveness, as well as patient satisfaction and compliance.


Systematic review Orthodontics Retainers Thermoplastic Clear Vacuum-formed 


Compliances with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© The Society of The Nippon Dental University 2016

Authors and Affiliations

  1. 1.Hamdan Bin Mohammed College of Dental MedicineMohammed Bin Rashid University of Medicine and Health SciencesDubaiUnited Arab Emirates
  2. 2.Department of Orthodontics and Dentofacial Orthopedics251 Hellenic Air Force V.A. General HospitalAthensGreece
  3. 3.Department of Orthodontics and Dentofacial Orthopedics, Faculty of MedicineUniversity of BernBernSwitzerland
  4. 4.Department of OrthodonticsAristotle University of ThessalonikiThessalonikiGreece

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