Many patients think that once the braces are off, their teeth will stay in their new positions forever; but this isn’t always right!
“But what if I wear my retainers?” We hear this question a lot. Retainers will most definitely minimise relapse, but most people’s bodies don’t remain static for the rest of their lives. Our bodies always keep growing and changing. This means teeth and the surrounding structures such as the bone, muscles, ligaments and other soft tissues tend to change shape and size. The body is dynamic, in tune with our environment and our genes.
Our environments and lifestyles can help shape our bodies indirectly through the food we eat, the air we breathe, how we breathe (nose or mouth), and habits such tongue thrusting and finger sucking. Other factors include physical or emotional stresses, diseases, infections, or tooth grinding.
And, of course, our genes we inherit from our parents can play a part in determining how our bones and soft tissues develop.
So why do teeth tend to relapse?
Over the years in our practice, we have observed that mouth breathing appears to be prevalent, consistent with other findings cited in dental journals who reported up to 55% of children tend to shy away from nasal breathing  . This phenomenon may be contributed by incidences of allergies and enlarged tonsils  , rendering restricted nasal airways, thus, breathing through the nose can be quite a challenge for many people.
Mouth breathing in turn, may contribute to narrowing of the upper jaw, causing crowded teeth5.
Whenever we see breathing through the mouth, we often also observe correlating degrees of crowded teeth and underdeveloped jaws. Every part of the patient's body may be shaped or moulded by the genetic and environmental factors described earlier. The jaw may be impacted by mouth breathing, the tongue drops down and the lips and cheeks tend to constrict the upper jaw. If we want functional stability and to minimise relapse, the most effective treatment may be extractions of 2 or more teeth*, which can create extra space and facilitate better teeth alignment.
If we expand the jaws, i.e. use a non-extraction treatment to accommodate the crowded mouth, the equilibrium will most likely be disrupted. It's like pushing a ball uphill, it always wants to roll back down. So, we think it is feasible to surmise that the chance of relapse is greater with jaw expansion in non-extraction cases.  
So how do we minimise relapse?
If we extract teeth, there will be less chance of a relapse but there could be a price to pay in the future. Remember if there is crowding in the first place, that means the jaw is already most likely underdeveloped. Taking teeth out will potentially shrink the jaws further. The consequences are possible TMJ (temporomandibular joint) pain  and OSA (obstructive sleep apnoea)  in the future.
If we just think about teeth, nothing but the teeth, extraction is sometimes the best option.
If we want to consider the body as a whole, we believe the best way forward is jaw expansion. But, of course, each case is different and will need to be assessed individually.
What is the best way to lower the risk of relapse?
In many cases, the best way to lower your risk of relapse is to use mixed and removable retainers for the next 3 months, which usually need to be worn 24/7. We’ll also need to observe 3 factors over the course of regular check-ups:
- Nasal breathing
- Lips close together at rest
- Tongue posture (tongue on the roof of the mouth)
As always, your treatment and overall well-being can be enhanced through exercising regularly, eating well, minimising stress, and having plenty of good quality sleep.
1. Mitchell, Laura. An Introduction To Orthodontics. 1st ed. Oxford: Oxford University Press, 2007. Print.T
2. The mouth breathing syndrome: prevalence, causes, consequences and treatment D Martins et al J Surg Cl Res – Vol. 5 (1) 2014:47-55
3. Prevalence of mouth breathing among children Rubens Rafael Abreu; Regina Lunardi Rocha; Joel Alves Lamounier et al. J Pediatr (Rio J). 2008 Sep-Oct;84(5):467-70
4. Page, D. and Mahony, D. 2010. The airway, breathing and orthodontics. Todays FDA 22, 2: 43-47. Accessed March 17, 2016: http://www.ncbi.nlm.nih.gov/pubmed/20443530
5. Mouth breathing: Adverse effects on facial growth, health, academics, and behavior Yosh Jefferson, DMD, MAGDJanuary/February 2010 General Dentistry www.agd.org
6. Janson G, Valarelli FP, Beltrão RT, de Freitas MR, Henriques JF. Stability of anterior open-bite extraction and non-extraction treatment in the permanent dentition. Am J Orthod Dentofacial Orthop. 2006 June;129(6):768-74.
7. Medeiros RB, Araújo LFC, Mucha JN, Motta AT. Stability of open-bite treatment in adult patients: A systematic review. J World Fed Orthod. 2012;1(3):e97-101.
8. Orthodontics and temporomandibular disorder: A meta-analysis Kim MR, Graber TM, Viana MA.
9. Sinha, D. and Guilleminault, C. 2010. Sleep disordered breathing in children. Indian Journal of Medical Research 131, 1: 311-320. Accessed March 17, 2016: http://icmr.nic.in/ijmr/2010/february/0221.pdf