The short answer
Both appliances move teeth by applying gentle, sustained pressure to bone — the difference is who controls that pressure and how much of it you can switch off. Fixed braces (feste Zahnspange) work around the clock whether you cooperate or not, and remain the more powerful instrument for complex movements: bodily root movement, badly rotated teeth, closing extraction gaps, large bite corrections. Clear aligners (Aligner) are removable, barely visible and far easier to clean around, and for a large share of adult cases they achieve the same result — provided they are worn 20 to 22 hours a day. The right choice is not decided by preference alone; it is decided by the finding, and a serious practice will tell you honestly when your case sits outside what trays do well.
What the two appliances actually do differently
Strip away the marketing and the mechanical difference is simple.
A fixed brace attaches the force system to your teeth. Small brackets are bonded to each tooth and connected by an archwire. The wire wants to return to its original shape, and as it does, it drags the teeth along with it. Because the wire is anchored to every tooth in the arch, the orthodontist can move one tooth against the resistance of all the others, tip a crown one way while pushing its root the other, and apply forces in three dimensions at once. Adjustments are made by changing wires, adding springs, elastics or auxiliaries. The system is under your dentist’s control, not yours.
An aligner surrounds the teeth with a shell that is deliberately slightly out of position. Each tray is manufactured a fraction ahead of where the teeth currently sit. When you seat it, the plastic flexes and pushes. That push is spread over the whole crown of the tooth, which makes the force gentle and even, but also means the tray has relatively little grip on a smooth, round tooth. This is what attachments (Attachments) are for: small tooth-coloured bumps bonded to specific teeth that give the plastic a surface to press against and turn a shell into a directional tool.
Both systems rely on the same biology. Sustained light pressure causes bone on one side of the root to be resorbed and new bone to be laid down on the other. That process runs at its own pace, and no appliance speeds it up beyond what bone will tolerate. Anyone promising dramatically faster results with the same biology is selling something.
Point by point
| Clear aligners | Fixed braces | |
|---|---|---|
| Visibility | Barely noticeable at conversational distance | Metal brackets clearly visible; ceramic less so |
| Removable | Yes — for eating, cleaning, photographs, a concert | No |
| Depends on your discipline | Heavily — 20–22 hours a day | Not at all |
| Range of movements | Very good for tipping, alignment, small gaps; limited for large root movements | The full range, including complex and skeletal cases |
| Eating | Nothing forbidden — trays come out | Hard, sticky and very chewy foods restricted throughout |
| Cleaning teeth | Normal brushing and flossing with trays out | Slower and more demanding around brackets and wire |
| Appointments | Short reviews at longer intervals | Regular adjustments; occasional emergency visits for loose brackets |
| Mouth comfort | Pressure in the first days of each new tray; smooth surfaces | Pressure after adjustments; possible rubbing on cheeks and lips early on |
| Speech | A slight lisp for the first days, usually settles | Usually unaffected after the first week |
| Contact sports and wind instruments | Trays can come out | Mouthguard needed; brass and woodwind players often need an adjustment period |
| Suitable for children in growth | Case by case | Long-established, including growth-guiding appliances |
Where fixed braces are still the stronger tool
This is the section most aligner marketing leaves out, and it is the reason we start with a diagnosis rather than a product.
Large bodily root movements. Tipping a crown is easy; moving an entire tooth — crown and root together — through bone is not. Fixed appliances do this more reliably because the archwire engages the tooth along its whole width.
Closing extraction gaps. Where a tooth has been removed and a substantial gap has to be closed, the anchorage demands are considerable. Brackets and wires handle this well; aligners can, but the case selection matters much more.
Severely rotated canines and premolars. Round teeth are hard to grip with a plastic shell. Attachments help, but there is a point beyond which a bracket simply has more purchase.
Teeth that are impacted or partly erupted. A tooth still buried in bone needs to be attached to a wire and drawn into the arch. A removable tray has nothing to hold on to.
Skeletal problems in growing patients. Where the jaws themselves are mismatched rather than just the teeth, growth needs guiding — a job for fixed and functional appliances, and sometimes for a combination with jaw surgery in adults.
Patients who will not wear trays. This is not a moral judgement, it is planning. If someone knows they will not manage 22 hours a day — irregular shifts, frequent travel, a teenager who is honest about it — a fixed appliance will deliver a better result than an aligner treatment that spends half its life in a pocket.
Where aligners have the clear advantage
Adult front-tooth crowding and relapse. The single most common adult request: lower front teeth that have crowded up over the years, or an upper arch that drifted after a retainer failed. Aligners handle these well and discreetly.
Gum health during treatment. You can take the trays out and clean normally. Brackets and wires trap plaque, and patients who struggle with cleaning often finish a fixed treatment with straight teeth and inflamed gums. If you already have a history of gum disease (Parodontitis), being able to clean unobstructed is a genuine clinical argument, not a comfort argument.
Predictable planning you can see in advance. Because the movements are planned digitally, you can look at the projected sequence before manufacturing begins. It is a prediction, not a promise — but it makes the conversation concrete.
Jobs and lives that are lived face to face. Teachers, client-facing consultants, people who present, people who are photographed. Visibility genuinely matters to them, and dismissing that as vanity misses the point: an appliance you will actually wear is worth more than a theoretically superior one you abandon.
No emergency appointments for a loose bracket. A cracked tray is annoying; a debonded bracket during a business trip is worse.
Everyday life: the part no quotation mentions
The 22-hour rule is not a suggestion. Aligners work while they are on the teeth and only then. The usual instruction is to wear each tray 20 to 22 hours a day, removing it to eat and to clean. That leaves roughly two hours a day for all meals combined. People who graze through the day find this harder than they expect — it is often the single biggest lifestyle change of the treatment.
Coffee, tea and red wine. Drink them with the trays out, or the plastic stains and so does the smile you are trying to improve. Water is fine with trays in.
Meetings and meals out. Removing a tray discreetly takes practice. Most people manage within a fortnight and stop thinking about it.
Sport. With fixed braces, a mouthguard is essential for contact sports. With aligners, the trays generally stay in for running, cycling and the gym; for boxing or martial arts, ask.
Musicians. Wind and brass players usually need a settling-in period with brackets, and some notice a difference with trays. If you play professionally, say so at the consultation — it changes the planning conversation.
Smokers. Smoking with aligners in discolours them quickly. It is worth knowing before, not after.
Cleaning the appliance itself. Trays are rinsed and brushed gently with a soft brush and cool water. Fixed braces need interdental brushes, a good technique and more time, and professional cleaning (professionelle Zahnreinigung, PZR) during treatment is genuinely useful with either system.
The hidden variable: honesty about your own discipline
Every experienced practice has seen the same two patterns. A motivated patient with a moderately difficult case finishes on time and delighted. An unmotivated patient with an easy case stretches a nine-month treatment across two years and blames the trays.
Before you choose, answer one question honestly to yourself: will I put them back in after lunch, every day, for a year? If the answer is a confident yes, aligners are open to you. If it is a shrug, say so at the consultation. Nobody will think less of you, and it changes the recommendation in a way that protects your result and your money.
Ceramic brackets and lingual braces: the middle ground
“Invisible” is not a single product. Ceramic brackets (Keramikbrackets) are tooth-coloured and considerably less conspicuous than metal, while keeping the mechanical strengths of a fixed appliance. Lingual braces (Lingualtechnik) sit on the inner surfaces of the teeth and are essentially invisible from outside, at the cost of a longer adaptation period for the tongue and speech. Both belong in the conversation if visibility is your main concern but the finding argues for a fixed system. Which of them fits which case is a longer subject in its own right — see Which invisible brace is best?.
Cost and cover, briefly
For adults in Germany, both routes are private. Statutory health insurance (gesetzliche Krankenversicherung, GKV) funds orthodontics only for patients under 18 whose misalignment reaches grade 3 on the KIG scale (Kieferorthopädische Indikationsgruppen, the national five-grade grading of orthodontic need) — and there it pays for fixed braces as standard care, with aligners counting as a private upgrade. Our aligner treatment is offered in three variants: 1,049 €, 2,800 € and 3,699 €, with the diagnosis deciding which applies. The full mechanics of cover, co-payments and instalments are set out in Invisible braces in Germany: what they cost.
Five situations, five recommendations
A 34-year-old consultant with mild lower crowding and a slightly rotated upper incisor. Classic aligner territory. Discreet, cleanable, manageable alongside a travelling job — as long as the trays go back in after airport meals.
A 15-year-old with a pronounced overbite and a canine still coming through. Fixed appliance. Growth can be used, the erupting tooth needs guiding, and cover may apply if the KIG grade reaches 3.
A 45-year-old with treated gum disease and drifting front teeth. Aligners are attractive here precisely because cleaning stays unobstructed — but only after the gums are stable. Orthodontics on inflamed gums is the wrong order.
A 28-year-old needing space closed after an extraction. Fixed braces are the more predictable tool. Aligners are possible in selected cases; this is a conversation to have with the actual X-rays in front of you.
A 52-year-old whose old retainer broke five years ago. Often a short, limited aligner correction — the sort of case that sits at the lower end of the price range, and one where the retainer afterwards matters more than the trays.
What is normal during treatment — and when to contact us
If your German is limited
Orthodontic treatment is a long conversation, not a single procedure: consent, planning, review appointments, small adjustments along the way. Doing all of that in a language you are still learning is unnecessarily hard, and misunderstandings in orthodontics tend to show up months later. We treat patients in English, and being 20–30 minutes from Düsseldorf, Cologne and Bonn means patients regularly travel to Wuppertal for treatment of this kind, some from well beyond NRW. If you are working out where to go, start with English-Speaking Dentist in NRW.
Not inherently. Both depend on the same rate of bone remodelling. What differs is reliability: a fixed appliance applies its force continuously, whereas an aligner only works when it is worn. In a well-selected case with good wear, treatment times are broadly comparable; in a poorly worn case, aligners take considerably longer.
Yes, and it happens. If teeth stop tracking the plan, the options are a new scan with a further series of trays, adding auxiliaries, or moving to a fixed appliance for part of the treatment. This is worth agreeing in advance so that both the clinical path and the cost of it are clear from the start.
They can. A short phase of fixed braces to handle a difficult movement, followed by aligners to finish, is a legitimate approach in selected cases. It is planned deliberately, not improvised.
Most patients describe aligners as more comfortable overall — smooth plastic, no wires, and the option of taking them out. But comfort is not the same as suitability, and the first days of each new tray still involve real pressure.
As a rule, yes. Both appliances make plaque control harder, so treatment starts from a healthy baseline: decay treated, gums settled, and usually a professional cleaning first. This is standard sequencing and worth doing properly.
Yes. Retention is not tied to the appliance you chose — it is tied to the biology of teeth wanting to move back. Expect a bonded wire behind the front teeth, a night-time retainer, or both, and expect that to be a long-term arrangement.
Aligners and fixed braces are not rivals so much as different instruments. Brackets remain the more powerful tool for complex movements and for patients who would rather not have to think about compliance. Aligners are discreet, easy to clean around and entirely capable in a large share of adult cases — as long as they are actually worn. Choose after a diagnosis, not after an advertisement, and be honest about your own routine. That single piece of honesty predicts the outcome better than any product comparison.
Zahnarztpraxis Tsypin · Wuppertal. This article was medically reviewed and is provided for information; it does not replace an examination. Updated August 2026.
