Simon described the concept of ‘no retention’, the methodology and literature on the topic, with his expert option included.

Conclusion

· Controversial to not wear retainers

· Simon still asks patients to wear retainers

· Interproximal reduction helps but we don’t know why

Classic study

Riedel and Little

· 10 years out of retention

· 70% relapse – require retreatment, 30% no retainers and no treatment needed

· No identifiable factors – therefore to keep teeth straight require retainers

Treatment protocol and retrospective study of no retainers

Aasen EJO 2005

· During treatment

1. Respect lower archform

2. Maintain lower incisor position

3. Overcorrect of rotations

4. Heavy final wire 21x25 SS for 2-3 months

5. Relapse ‘test’: 4 weeks no archwire

· Results

1. After 3 years 1.1mm (Little’s Index)

§ Not significant clinical change

Randomised control trial Lower arch

Tynelius 2010, 2013

· Lower bonded retainer Vs IPR and no retainer

· 2 years = no difference in stability

Randomised control trial Upper arch

Naraghi 2020

· Upper VFR Vs no retainer

· 1 year follow up

o Relapse with retainer 0.4mm

o Relapse without retainer 1.3mm

· Not clinically significant

Post – treatment changes

1. Relapse

2. Age related changes

a. Abdulraheem 2020, 12 year follow up

i. Tooth displacement index

1. 25% = age related

2. 75% orthodontic relapse

Reference

Aasen, T.O. and Espeland, L., 2005. An approach to maintain orthodontic alignment of lower incisors without the use of retainers. The European Journal of Orthodontics, 27(3), pp.209-214.

Edman Tynelius, G., Bondemark, L. and Lilja‐Karlander, E., 2013. A randomized controlled trial of three orthodontic retention methods in C lass I four premolar extraction cases–stability after 2 years in retention. Orthodontics & craniofacial research, 16(2), pp.105-115.

Naraghi, S., Ganzer, N., Bondemark, L. and Sonesson, M., 2020. Comparison of post-treatment changes with and without retention in adolescents treated for maxillary impacted canines—a randomized controlled trial. European Journal of Orthodontics.

Tsiopas, N., Nilner, M., Bondemark, L. and Bjerklin, K., 2013. A 40 years follow-up of dental arch dimensions and incisor irregularity in adults. The European Journal of Orthodontics, 35(2), pp.230-235

Abdulraheem, S., Schütz-Fransson, U. and Bjerklin, K., 2020. Teeth movement 12 years after orthodontic treatment with and without retainer: relapse or usual changes?. European Journal of Orthodontics, 42(1), pp.52-59