An appliance is a surface, and surfaces get colonized
Plaque forms on any solid surface in the mouth, not only on teeth. A retainer, a clear aligner, a sports mouthguard or a removable appliance develops its own film within hours, and unlike a tooth, it also has crevices and a fitting surface pressed against the gums for hours at a time.
That has two consequences. The appliance itself becomes a reservoir that reintroduces bacteria to a mouth you have just cleaned, and the tissue underneath it sits in contact with that film. Inflamed gum tissue under a poorly cleaned appliance is a common and entirely avoidable finding.
There is also the mundane matter of smell, which is what usually prompts a teenager to do something about it. Whatever gets the job done.
The cleaning that generally works
Rinsing immediately after removal, before anything dries onto the surface, does a surprising amount of the work. Beyond that, most practices advise gentle brushing with a soft brush and water, and a soaking solution intended for the appliance where one has been recommended.
What is appropriate varies by material, which is the reason I am not going to prescribe a method. A clear thermoplastic aligner, an acrylic retainer with a wire, a fixed retainer bonded behind the teeth and a sports guard are different objects, and the instructions that came with yours exist for a reason. Ask the practice that supplied it if you have lost them.
The general principle worth holding is that the appliance should be cleaned every time it comes out, and stored dry in its case when it isn’t being worn, with the case itself washed periodically since it accumulates its own film.
The methods that damage things
Hot water is the most frequent casualty. Thermoplastic aligners and retainers distort with heat, and a retainer washed under a hot tap or left in a car in summer may no longer fit — which is a genuinely expensive mistake, and a common one.
Toothpaste is more abrasive than many appliance materials tolerate, and it can leave a scratched, cloudy surface that then holds plaque more readily. That is why so many instructions specify a brush with water rather than paste.
Household bleach, strong disinfectants, alcohol-based products and boiling are all things people try, and all of them can damage the material, leave residues that irritate tissue, or both. Denture cleaning tablets are sometimes suggested for certain appliances and are not automatically suitable for others, particularly those with metal components. This is one of the places where following the specific instruction beats improvising.
The habits around wearing them
Nothing should be eaten with clear aligners in place, and drinks other than water are best avoided while they are worn, since liquid is held against the tooth surface by the appliance and can’t be cleared by saliva. A sugary drink under an aligner is a prolonged exposure in a sheltered space, which is close to a worst case.
Teeth should be brushed before an appliance goes back in wherever practical, so a clean surface is being covered rather than a film sealed in place. After school lunch this is often unrealistic, and rinsing well is a reasonable fallback.
A fixed retainer bonded behind the front teeth is a different situation, since it cannot be removed. It creates a trap for plaque and calculus along its length, and cleaning under the wire requires threading floss or using a small interdental brush. Anyone with one should expect a specific demonstration and should mention it at every hygiene visit.
When something is wrong
An appliance that has become uncomfortable, that rubs a sore spot, or that no longer fits should be looked at rather than persevered with or adjusted at home. A sore area under an appliance that lasts more than about two weeks needs examining, as with any persistent ulcer in the mouth.
Gum tissue that is swollen or bleeding where an appliance sits is a signal that cleaning is not keeping up, and it is worth raising promptly rather than waiting for the next scheduled visit.
And a retainer that has been out of use for a while should not simply be forced back in. Take it to the practice instead. Whether it still fits, and what should happen if it doesn’t, is a clinical question with an easy answer for anyone who can see your teeth and an impossible one for anyone who cannot.
Common questions
Can I use mouthwash to soak a retainer?
Some mouthwashes contain alcohol or colorants that can affect appliance materials, so it is not a default choice. Use whatever the supplying practice recommended, and ask if you are unsure rather than experimenting with something that could cloud or weaken it.
How often should a sports mouthguard be replaced?
When it no longer fits well, when it is damaged, or when a growing child’s mouth has changed, which for a young athlete can be within a season. A guard that fits poorly protects poorly, so fit is the criterion rather than time.
My aligner smells even after cleaning. Why?
Persistent odor usually means film in scratches or crevices, or that the appliance is being put back over teeth that have not been cleaned. It can also indicate the material has aged. Mention it at your next visit, since it may simply be due for replacement.
Dental Surgeon, Dr. Shruti Goel
Dr. Shruti Goel is a dental surgeon in practice since 2006 — around 20 years of clinical work — at Advanced Dental Clinic in Faridabad. She writes here about hygiene and prevention: the part of dentistry that happens at home, between appointments, and that decides how much of the rest is ever needed.