Retention, What Should We Do Now? 13 MINUTE SUMMARY

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Retention, What Should We Do Now?

Join me for a update on retention, I explore a review of current literature and what the changes are recommended to our retention protocols, research of stability,  critical look of retainer failures and factors to consider in design and location of fixed retainers, as well as monitoring recommendations based on Clinical Practice Guidelines. This podcast is based on recent literature as well as two excellent lectures from this year’s British Orthodontic Conference by Marie Cornelis (Australia) and Simon Littlewood (UK).

Stability

Maxilla

• Stability of maxillary anterior teeth maintained both with removable alone as well as fixed and removable equal = Bjering 2015
• Maxilla 3-3 Vs 2-2, no significant difference in overall irregularity statistically significant but not clinically significant difference in canine rotation 2.4 degrees, Naraghi 2021
• No difference in full time Vs night time wear Gill 2007 & Thickett 2010

Mandible

• At 6 months no difference in fixed Vs removable Simon Littlewood 2023
• At 12 months shows tendency of better stability fixed that removable
• At 24 months show greater stability fixed Vs removable O’Rouke 2016 1.52 (0.75-2.29)
• Long term 4 years fixed appliance better than removable by 1.64mm (1.23 Vs 3.16)  Moghrabi 2018

9-year follow up study Cornelis 2023

• Prognostic factors – presence of fixed retainers prognostic factor as well as lower irregularity at completing orthodontics (Coef -11.10, 95% Ci -15.74, -6.56)

Failures of removable retainers

• Greater failure when full time removable wear Millett 2007
  • VFR 40% greater failure’s than Hawley Sun 2011
• VFR night only, Bilinska 2025
  • 12 months failures 35%
  • 24 months failure 63%
    • Mainly occlusal wear for failure

Failure of fixed retainers?

• Overall failure rate 35% Aye 2023 SR
• Similar failure rates of maxilla than mandible 37% Vs 39%.
• Short term 24% 6 months, medium term 41% 1-4 years, long term 53% 5-6 years Aye 2023.
• Most common = bond failure at the composite-enamel interface most common Bovali 2014
• Most common breakage: Maxilla lateral incisor – upper canine (Littlewood), mandible lower incisors (Johal 2025)
• Timing of fixed retainer failure
  • First 1-6 months,

Design: Number of teeth

• Maxilla
  • 3-3 gold standard
    • 2-2 consider when inter-occlusal space not sufficient, which is common Marie Cornelis and Simon Littlewood recommendation
  • Maxilla 3-3 Vs 2-2, no significant difference canine rotation 2.4 degrees, Naraghi 2021
• Mandible
  • Recommend 3-3

Design – 4 x materials

1. Braided stainless steel
   • 21 least failure at 12% Tacken 2010
   • Smaller the wire = greater failure tendency Iliadi 2015
   • 3 strand Vs 5 strand = 3-4 x greater failure Dahl 1991
2. CAD-CAM Ni-Ti retainers (Memotain)
   • No difference in failure rate (although high at 40%) or Littles index when compared to multistranded wires 2 year follow up Pullisaar 2024
   • Uk study showed 50% failure Jowett 2022
3. Flat rectangular wire: Johal 2025 2 year follow up

• 03 x 0.01 rectangular and flat, advantage = chairside, adaptable and passive
• Flex-tech (direct) survival 96%
• Multistrand SS (indirect) survival 92%

4. Blu-Elgiloy

• Canine and canine – Greatest failure at 2 years of 32% Johal 2025

• Bonding material
  • Conventional orthodontic composite lower failure rate Vs flowable composite 6% Vs 12% Scribante 2020

• Repeated failures
  • Same tooth – 21%-28% Bovali 2014 Taner 2012
  • Rebonding of multistranded wire = lower bond strength in-vitro Cooke 2010
    • Possibly due to unpredictable bonding to previous enamel and full removal

Future direction

• Braided stainless steel no longer the gold standard, failures + side-effects of ‘X effect’ (torque), ‘twist effect’ (tipping)  4-5% of fixed retainers Katsoras 2007, Renkema 2011
  • Wire not passive – active component during manufacturing
  • Deformed on insertion by operature – induce elastic deflection on bonding
  • Deformed by function – hard foods trauma, flossing
• Robot bent retainers: Less relapse at 6 months Shim 2022
• Electronic bracket debond and removable retainer fit, ElShebiny 2024

Recommendations for the maxilla:

• Low risk of relapse = Removable retainer (polyethylene or polyurethane)
• High risk of relapse = Dual retention with fixed and removable retainers
• Fixed retainer
  • 3-3 if occlusion allows, most likely 2-2 design unless high risk of canine relapse
  • Location slightly gingival due to occlusal forces and account for Increase in overbite with age (Littlewood)

Recommendations for the mandible

Lower arch

• Low risk of relapse = fixed retainers
• High risk of relapse = dual arch
• Fixed retainer 3-3
  • Position slightly incisal Mandible: slightly more incisal, greater cleanability, less gingival inflammation – Petsos 2023

Monitoring regime

• 1 month – fixed retainer (greatest timepoint of failure)
• 3 month – removable retainer (motivation of compliance)
• Every 3-4 months Wouters 2018
• 1 year retention necessary Wouters 2018
• Annual check-up Wouters 2018
  • Greater likelihood of compliance if annual check-up
  • General dentist

Improve compliance

• 2/3^rds stop wearing after 4 years, All-Moghrabi 2018
• Visual photo of relapse to patient and parents increased compliance Vs patient only or instructions only Lin 2015 (1.5Hrs greater wear)

Clinical Practice Guideline For Orthodontic Retention Wouters 2019 (open access paper)