Invisalign vs. braces
“Invisalign” is one brand of clear aligner, made by Align Technology — this page covers clear aligners as a category, against traditional fixed braces. Same biology, two very different daily lives. Here is what each can actually fix, what each demands of you, what the evidence says about root damage, and what happened to the mail-order companies that promised to skip the dentist entirely.
Neither is “better” — both move teeth the same way, with steady pressure. Clear aligners handle most mild-to-moderate crowding, spacing, and bite problems and come out for eating; fixed braces handle severe rotations, extraction cases, and jaw-level problems and work 24/7 whether you cooperate or not. The appliance matters less than the case — and the person planning it.
How to read the numbers on this page: treatment lengths and costs are estimates drawn from the sources cited at the bottom — AAO guidance and peer-reviewed studies — not promises about your case. Where we could not verify a figure (Tennessee-specific ortho pricing, for example), we say so instead of filling the gap.
How each one actually moves teeth
Strip away the marketing and the two appliances are the same treatment wearing different clothes. Both apply gentle, steady pressure to a tooth; the pressure signals the bone around the tooth to remodel — dissolving on one side, rebuilding on the other — so the tooth can drift into its new position. Everything else is about how the pressure gets delivered, and who has to remember to deliver it.
A Fixed braces: bonded on, always working
Metal or ceramic brackets are bonded to each tooth and connected by an archwire — the wire that applies the continuous force. Your orthodontist adjusts or tightens that wire about every 4–6 weeks, steering the teeth in stages.
Because braces are glued on, they work around the clock. There is no daily decision to make and nothing to lose, forget, or leave in a napkin at lunch. The trade-offs: they're visible, food gets trapped around them, brushing and flossing take real technique, and hard or sticky foods are off the menu.
B Clear aligners: a planned sequence of trays
Your mouth is 3D-scanned, the full tooth movement is planned in software, and a series of custom clear plastic trays is manufactured. Each tray is shaped a fraction of a millimeter different from the last; you wear each one for about 1–2 weeks, then switch to the next, and your teeth move to fit.
Small tooth-colored bumps called attachments are often bonded to the teeth so the trays can grip and push in directions smooth plastic alone couldn't. The trade-offs: trays are nearly invisible and come out for eating and brushing — but they only move teeth while they're in your mouth, which is the whole subject of the compliance section below.
The AAO's position, worth memorizing
The American Association of Orthodontists: “One appliance is not inherently better than another. What is used for an individual's correction will be based on the goals of treatment and the patient's lifestyle needs… The type of appliance used in orthodontic treatment is far less important than the skill in the hands of the person who is providing the treatment.” If a practice steers every single patient to one appliance, that's a sales pattern, not a clinical one.
Side by side
The honest head-to-head. Ranges below are the sourced figures used throughout this page — see each section for the detail and the citations.
| Fixed braces | Clear aligners | |
|---|---|---|
| How it works | Brackets bonded to the teeth, joined by an archwire adjusted every 4–6 weeks. | A sequence of removable trays, each worn 1–2 weeks, planned from a 3D scan. |
| Wear requirement | 24/7 — bonded on. No compliance decision exists. | 20–22 hours a day. Out only to eat, drink anything but tap water, and clean your teeth. |
| Typical treatment length | 18–24 months Severe cases 24–36 months | 6–18 months Mild-to-moderate cases |
| National cost range (2026) | $3,000–$8,000 | $3,000–$8,000 |
| Best for | Severe or complex cases, big rotations, vertical tooth movement, extraction cases, patients who won't wear trays. | Mild-to-moderate crowding and spacing, most common bite issues, adults who prioritize discretion. |
| Eating & cleaning | Food restrictions; careful brushing and flossing around hardware. | No food restrictions — but brush before trays go back in, every time. |
| Root resorption (Li et al., CBCT) | Seen in 82.11% of roots; mean severity 1.12 mm. | Seen in 56.30% of roots; mean severity 0.13 mm. |
Sources: AAO patient FAQs (wear time, tray changes); AAO-cited treatment averages; Li et al. CBCT study, PubMed Central (PMC6943096). Full citations in Sources & method. The cost range is verified national data — we found no trustworthy Tennessee-specific ortho price survey, so we don't present one.
What each can fix — and what neither can
This is the section that decides the question for most people. Aligners have gotten genuinely capable — clinical summaries report they now address the large majority (one summary of an American Journal of Orthodontics and Dentofacial Orthopedics finding puts it around 90%) of mild-to-moderate alignment issues. But “most cases” is not “your case,” and the limits are real and specific.
| Problem | Clear aligners | Fixed braces |
|---|---|---|
| Mild–moderate crowding or spacing | Handle well — this is their home turf. | Handle well. |
| Overbite, underbite, crossbite, open bite Mild to moderate | Generally yes, often with rubber bands or attachments. | Yes. |
| Severe crowding or spacing needing extractions | Not recommended — a peer-reviewed review of aligner therapy says aligners should not be used here; the trays are “likely not going to be strong enough.” | Yes — the standard tool for closing extraction space with control. |
| Big rotations Roughly beyond 20 degrees | Difficult with aligners alone; round teeth give trays little to grip. | Yes — more predictable torque and rotation control. |
| Vertical movement Pulling a tooth down (extrusion) or pushing it up (intrusion) | Limited; plastic pushing on a tooth's side is a weak way to move it vertically. | Yes — wires do this predictably. |
| Jaw-size or jaw-position problems Severe skeletal Class II/III, major facial asymmetry | No appliance fixes this. Teeth can be camouflaged, not corrected. | Braces alone can't either — this is orthognathic (corrective jaw) surgery territory, with braces or aligners before and after. |
Sources: peer-reviewed review of clear aligner therapy (PubMed Central, PMID 37881665) on extraction and skeletal cases; clinical comparisons of appliance capability for rotation, torque, and vertical movement.
The question to ask at any consultation
“Is my problem a tooth-position problem or a jaw problem?” Tooth position is appliance territory. Jaw size and position are not — and no tray, however advanced the software, changes that. A clinician who blurs that line to sell you aligners is telling you something about the rest of the plan, too.
How long it takes — and what makes it take longer
The averages: braces run 18–24 months for a typical case, and severe cases can run 24–36 months. Aligners run 6–18 months for the mild-to-moderate cases they're suited to. Read those ranges carefully — they describe different case mixes. Aligners look “faster” largely because they're used on simpler problems, and any honest comparison starts there.
01 Case complexity
The dominant factor, for both appliances. More distance to move, more rotations, bite correction on top of straightening — every addition adds months. This is also why a real timeline estimate requires an exam and records, not a photo upload.
02 Age
Adult teeth are more firmly set in the jaw, and adult bone remodels more slowly. The AAO notes adult treatment may take longer for exactly this reason. Longer is not worse — it's biology, and a realistic adult timeline beats an optimistic one.
03 Compliance
Aligners worn 14 hours a day instead of 22 don't move teeth 60% as fast — they mostly don't move them at all, and teeth drift back between wears. Rubber bands skipped, appointments missed, trays changed late: each one stretches the calendar. With braces, compliance mostly means showing up and not breaking hardware.
04 Mid-course corrections
Teeth don't always follow the plan. Aligner cases commonly need a refinement — a fresh scan and an extra set of trays partway through. Braces cases get wire changes and added mechanics. Neither is a failure; both add time, and a quote should tell you whether refinements are included in the fee.
About the “faster than braces” claims
You'll see aligner marketing — and plenty of dental blogs — claim treatment is some specific percentage faster than braces. We looked for the studies behind those numbers and could not find them cited anywhere, so we won't repeat the percentages here. Treat any percentage-speed claim with no source attached as advertising, and be wary of a practice that repeats it as fact.
The 20–22 hour rule: aligners are a part-time job
This is the single biggest practical difference between the two treatments, and the one most often glossed over at the sales pitch. The AAO's FAQ is blunt: “Aligners need to be worn at least 22 hours a day. Take them out to eat or to drink anything except for tap water. Then clean your teeth before putting your aligners back in. They can only move teeth when they are in your mouth.” Most systems put the guideline at 20–22 hours a day.
- Do the math on “out.” At 22 hours in, you get two hours a day for all eating, drinking, and tooth-cleaning combined. Three meals, a coffee, and a snack can eat that budget fast — coffee drinkers and grazers feel this rule most.
- Only tap water with trays in. Coffee, tea, soda, juice, wine — all of it means trays out, because hot drinks can warp plastic and everything else bathes your teeth in sugar and acid under a sealed tray.
- Brush before they go back in. Every time. Trapping food and plaque against enamel under plastic for hours is a cavity recipe, which is why “I'll just rinse” quietly becomes a dental problem by month three.
- Skipped days reverse progress. Teeth begin drifting back toward where they started. Miss enough time and the next tray no longer fits — which can force a rescan and a refinement phase, adding weeks or months and sometimes cost.
- Be honest with yourself before you pay. If your honest answer is “I'll wear them most of the time,” braces are the better appliance for you. That's not a character flaw; it's the exact lifestyle question the AAO says should drive the choice.
Orthodontics as an adult: no age limit, some fine print
About one in four orthodontic patients is an adult, per the AAO — and there is no upper age limit. The AAO's line is worth quoting whole: “Healthy teeth can be moved at any age.” Patients in their 60s, 70s, and 80s get treated. What changes with age isn't permission; it's the surrounding conditions.
01 Bone and timeline
Adult teeth sit more firmly in denser, less metabolically active bone. Movement is the same process, but it generally takes more time and sustained pressure. Expect your timeline estimate to run toward the longer end of the ranges above — and be suspicious of one that doesn't.
02 The mouth you already have
Adults arrive with history: crowns, implants, missing teeth, gum disease. An implant, unlike a natural tooth, cannot be moved — treatment has to be planned around it. Active gum disease has to be treated first or coordinated with a periodontist, because moving teeth through inflamed, bone-losing gums makes both problems worse. A good adult plan coordinates with your general dentist rather than pretending none of this exists.
03 The professional question
“Will this look childish at work?” is the fear adults ask about most. In practice, clear aligners are difficult to notice in conversation, and a quarter of the people in the waiting room are adults making the same choice. Braces patients can also choose ceramic (tooth-colored) brackets to cut visibility. The one real, temporary side effect: a slight lisp on s, z, sh, ch, and th sounds while your tongue adapts — typically gone within a few days to 1–2 weeks with aligners. A 2023 study of 40 patients found both appliances affected speech at first, aligners more so — and “at first” is the operative phrase. It is not permanent.
04 Paying for it as an adult
Most dental plans do not cover adult orthodontics. Some offer an annual or lifetime maximum toward it — read your plan for the word “lifetime,” because ortho maximums often work differently from your regular dental maximum. HSA and FSA funds can generally be used for orthodontic payments, which at least lets you pay with pre-tax dollars.
Retainers: the treatment after the treatment, forever
Nobody puts this in the brochure: orthodontics doesn't end when the braces come off or the last tray is done. The AAO's direct answer to “how long will I need to wear a retainer?” is: “Typically, a retainer is necessary for a lifetime, though the frequency of wear may decrease over time.” Teeth move throughout your life — aging, grinding, and gum changes keep nudging them — and the retainer is what holds the result you paid for.
| Type | What it is | Good to know |
|---|---|---|
| Fixed / bonded | A thin wire glued behind the front teeth. It stays in — you can't take it out. | The default recommendation for forgetful wearers and high relapse-risk cases. You never have to remember it, but flossing around it takes a threader or a water flosser, and it needs checking at cleanings in case a bond fails. |
| Clear removable Essix-style | A clear plastic tray, looks just like an aligner, covering the full arch. | Nearly invisible and typically worn at night after the initial phase. It also guards against grinding wear. Plastic fatigues — expect to replace it every few years, and ask at the outset what replacements cost. |
| Hawley | The classic retainer: acrylic plate plus a metal wire across the front teeth. | The most visible and the most adjustable — an orthodontist can tweak the wire to nudge minor settling, which a clear tray can't do. Durable, and the easiest to repair. |
The typical wear pattern: near-full-time for the first 3–6 months after treatment, when teeth are most prone to shift, then nighttime wear indefinitely. Whether your quote includes the first retainer set — and what replacements cost — varies by practice; ask before you sign, not after the braces come off.
A number we won't print
Dental blogs commonly repeat a specific relapse percentage, usually attributing it to the AAO. We searched the AAO's own pages for that figure and could not find it there, so we're not repeating it as fact. What the AAO does say, on the record, is enough: retainers are typically for life. The risk of shifting isn't a scare stat — it's the stated reason retention exists.
Root resorption: the fear, checked against the evidence
One of the most common worries about aligners is that they can cause root resorption — the body shortening a tooth's own roots. Here is the honest version: resorption is a real risk of all orthodontic tooth movement, braces included. But when researchers measure it, aligners come out lower — quantifiably lower — than fixed braces. Not zero. Lower.
| Measure | Clear aligners | Fixed braces |
|---|---|---|
| Roots showing resorption | 56.30% | 82.11% |
| Mean severity | 0.13 ± 0.47 mm | 1.12 ± 1.34 mm |
The pattern holds across the wider literature. A systematic review and meta-analysis by Fang et al. (11 studies) found external root resorption significantly lower with aligners than with fixed appliances (SMD −0.65, 95% CI −0.74 to −0.55). A 2025 systematic review in Dentistry Journal (10 studies, 575 patients, average follow-up ~22.6 months) likewise found less resorption with aligners for nearly all incisor types, with mean differences favoring aligners from −0.64 mm (upper central incisors) to −0.26 mm (lower central incisors) — while noting more research is needed on how much the difference matters clinically.
What this means for your decision
If root damage is your main argument against aligners, the evidence points the other way: of the two options, aligners carry the lower measured risk. Severe resorption is uncommon with either appliance, and monitoring is part of competent treatment either way — your clinician should be taking periodic X-rays during treatment and flagging any root changes, whichever appliance you choose.
The mail-order experiment, and how it ended
For about a decade, direct-to-consumer companies sold a seductive shortcut: skip the orthodontist, take impressions or a scan at a shop, get trays by mail, pay less. The two biggest names in that market are gone, and the way they went is the most instructive consumer story in modern orthodontics.
01 SmileDirectClub: shut down December 8, 2023
The largest mail-order aligner company — roughly 2 million past and present customers — filed Chapter 11 bankruptcy in September 2023 and, on December 8, 2023, shut down operations worldwide. Outstanding aligner orders were canceled, customer service ended, and its “lifetime guarantee” ended with it. Patients mid-treatment were simply stranded.
Worse, some customers on financing plans kept being billed by the third-party lender after treatment stopped. In late 2024, New York Attorney General Letitia James recovered $4.8 million for more than 28,000 consumers nationwide who were improperly charged after the shutdown.
02 Byte: suspended October 24, 2024
Byte, owned by Dentsply Sirona since 2021, voluntarily suspended sales and marketing on October 24, 2024, in consultation with the FDA, while it reviewed regulatory requirements. By January 2025 the company said Byte aligners would no longer be offered to new patients. The AAO had met with the FDA in July 2024 to share clinical concerns about mail-order treatment models.
The ADA's response to the SmileDirectClub closure (December 12, 2023) restated its position: a dentist is “ultimately responsible for the patient's care and is the only individual licensed and qualified to accept responsibility,” and it urged stranded patients to see a local dentist in person. The AAO had earlier filed complaints with 36 state dental boards over direct-to-consumer practices.
One side note, stated carefully
In December 2024, a litigation vehicle for SmileDirectClub's creditors (CDS) sued the ADA, the AAO, and Align Technology in California, alleging a coordinated antitrust campaign to drive SmileDirectClub out of business. Those are allegations in a lawsuit, not findings — the suit's outcome is not established, and it doesn't change the practical lesson: whoever you buy treatment from, the person legally responsible for your care should be a licensed clinician who has examined you in person and will still be there in year two.
What it costs — and what moves the number
The verified national range for a full course of orthodontic treatment in 2026 is $3,000–$8,000 — for braces and for aligners alike. Anyone who tells you aligners are categorically cheaper (or categorically pricier) is flattening a range that wide because case mix, not appliance, does most of the pricing. We could not find a trustworthy Tennessee-specific price survey for orthodontics, so the range on this page is the national one, labeled as such.
01 Complexity and length
The dominant drivers, again. A six-month touch-up of mild crowding and a three-year bite reconstruction are both “orthodontics,” and they sit at opposite ends of the range. Every extra month of treatment is chair time, trays or wires, and monitoring you're paying for.
02 Provider and market
Specialist orthodontists and metro practices generally price above general dentists and smaller markets — see the credentials section below for what that premium buys. Prices also vary by what the local market bears; there is no state fee schedule for private orthodontics.
03 Refinements and extra trays
Aligner cases that need a mid-course rescan and additional tray sets can cost more in time and, in some offices, in fees. Ask whether the quoted case fee includes refinements — and how many — before treatment starts.
04 What's bundled into the quote
Does the fee include retainers? Follow-up and retention visits? Replacement trays if you lose one? Two quotes a few hundred dollars apart often differ in exactly these line items. The consultation is where this gets settled — get the fee itemized in writing, including the payment-plan and insurance review, before you commit.
Insurance, briefly: children's orthodontics is covered on more plans; adult orthodontics is commonly excluded or capped by a lifetime maximum (see the Adults section). HSA/FSA funds can generally be used. For the full picture of how dental coverage pays, see our Tennessee cost guide.
Orthodontist vs. general dentist: the credential difference
Both start from the same degree. What happens after dental school is the entire distinction — and it matters most exactly when a case stops being simple.
| General dentist | Orthodontist | |
|---|---|---|
| Dental degree | DDS or DMD — about 4 years of dental school, then state licensure. | Same DDS or DMD, same licensure — the starting point is identical. |
| Specialty training | None required. General dentists may legally offer braces and aligners in many states without specialty training. | An additional 2–3 year accredited orthodontic residency devoted to tooth movement, bite correction, and facial growth — roughly 3,700 hours of specialty training. |
| Board certification | — | Optional, through the American Board of Orthodontics, requiring additional examinations. Not all orthodontists are board-certified; it's a plus, not the baseline. |
| Case focus | All of general dentistry; orthodontics is one service among many. | Only tooth movement and bite correction — that's the whole practice. |
The AAO's consumer guidance makes two points worth keeping: only a small percentage of dentists go on to become orthodontists, so offering orthodontic treatment does not by itself make a dentist an orthodontist — and many AAO orthodontists offer free or low-cost initial consultations, which makes “get a specialist's read on a complex case” a cheap step. You can verify any Tennessee provider's license and specialty status through the Tennessee Department of Health's Licensure Verification portal.
- Ask who's planning your treatment. With aligners, a clinician designs and approves the tooth-movement plan — ask whether that's the person in front of you, and whether they're an orthodontist.
- Ask the tooth-vs-jaw question. “Is my problem tooth position, jaw position, or both?” The answer determines whether any removable appliance is even a candidate.
- Get the fee itemized. Records, trays or braces, refinements, retainers, and follow-up visits — in or out of the quoted number, in writing.
- Ask what happens if trays don't track. The honest answer involves rescans and possibly switching to braces for part of the case. “That never happens” is not an answer.
- Ask about the retention plan up front. Which retainer type, worn how, for how long — and what replacements cost. If the plan has no retention chapter, it isn't finished.
- Take your records for a second opinion on big cases. Your X-rays and scan are yours. A clinician confident in a plan won't mind it being checked.
Red flags, whichever appliance you choose
None of these requires walking out on the spot. All of them are reasons to slow down and get a second read before money changes hands.
Trays sold with no in-person exam
No X-rays, no gum check, no one looking in your mouth before teeth start moving. The SmileDirectClub and Byte story above is what this model looks like at scale. Moving teeth without records is how undiagnosed gum disease and cavities get moved along with them.
“Faster than braces” percentages
Percentage-speed claims circulate through aligner marketing with no study cited behind them. If a practice uses one, ask for the source. An honest answer is a timeline range for your case, not a percentage off someone else's.
A quote that won't mention retainers
Retention is lifetime and part of the treatment. If the fee presentation ends at “straight teeth” with no retainer type, schedule, or replacement cost, you're comparing an incomplete price.
“Orthodontics” in the ad, no orthodontist in the office
General dentists can legally offer aligners in many states — but the ad copy sometimes implies specialty training that isn't there. Verify the license and specialty through the Tennessee Department of Health portal; it takes a minute.
Every patient gets the same appliance
A practice that puts 100% of cases in aligners — or 100% in braces — is selling its inventory, not diagnosing. The AAO's position is that the appliance follows the case and the patient's life, not the other way around.
Financing pressure before diagnosis
A payment plan pitched before records are taken and a plan exists is a sales funnel. Legitimate offices quote after diagnosis and will put the itemized fee in writing for you to take home.
Questions people actually ask us
In patients' own words — including the fears, because the fears are usually the real question.
Aligners are removable and nearly invisible, and you take them out to eat and brush normally — but they only work while they're in your mouth, 20–22 hours a day, and they struggle with severe rotations, extraction cases, and jaw-level problems. Braces are bonded on and work around the clock with nothing for you to remember, and they handle complex movement more predictably — but they're visible, harder to clean around, and come with food restrictions. For mild-to-moderate cases, either can work; the case and the clinician matter more than the appliance.
No. The American Association of Orthodontists puts it plainly: healthy teeth can be moved at any age, and patients in their 60s, 70s, and 80s get orthodontic treatment. About one in four orthodontic patients is an adult. The requirement isn't age — it's healthy teeth and gums. Adult treatment can take a bit longer because adult teeth are more firmly set in the jaw.
You're in plenty of company: about one in four orthodontic patients is an adult, per the AAO. Clear aligners are hard to spot at conversational distance, which is the main reason adults choose them. One honest caveat: many wearers notice a slight lisp on s, z, and th sounds for the first few days to two weeks while the tongue adapts. Studies find both aligners and braces affect speech at first, aligners a bit more — and the effect is temporary, not permanent.
Root resorption — the body shortening a tooth's roots — is a real risk of all orthodontic treatment, but the evidence says it's less common and less severe with aligners than with braces, not more. In a CBCT study by Li and colleagues, resorption showed up in 56.30% of aligner-treated roots versus 82.11% with fixed braces, and average severity was 0.13 mm versus 1.12 mm. Aligners don't eliminate the risk; severe resorption is uncommon with either appliance.
They will try to. Teeth move throughout your life — aging, grinding, and gum changes keep nudging them — which is why the AAO's answer to 'how long do I wear a retainer?' is: typically for a lifetime, though how often you wear it decreases over time. Expect near-full-time wear for the first 3–6 months, then a retainer at night indefinitely. Skipping the retainer is the most common way people undo treatment they paid thousands for.
The track record is not reassuring. The largest mail-order company, SmileDirectClub, shut down worldwide on December 8, 2023, mid-treatment for many customers, and Byte suspended sales on October 24, 2024 while reviewing FDA requirements. The ADA and AAO both hold that moving teeth is a medical process that needs an in-person exam, X-rays, and ongoing supervision by a licensed dentist or orthodontist. If a company will sell you trays without ever examining you in person, that is the risk you're being asked to carry.
For mild-to-moderate cases, clear aligners typically run 6–18 months. Traditional braces average 18–24 months, and severe cases can run 24–36 months. What stretches any timeline: how complex the case is, your age, and — with aligners especially — whether you actually wear the trays 20–22 hours a day and keep your appointments. Be skeptical of any ad promising a fixed percentage 'faster than braces'; those numbers circulate without studies behind them.
Legally, general dentists can offer braces and aligners in many states, and many do straightforward cases well. The difference is training: after the same 4 years of dental school, an orthodontist completes a 2–3 year accredited residency focused only on moving teeth and correcting bites — roughly 3,700 additional hours of specialty training. For a mild alignment touch-up, a general dentist may be fine. For bite problems, extractions, or anything complex, that specialty training is what you're paying for. Ask whoever treats you how they were trained and how many cases like yours they've done.
Sources & method
- American Association of Orthodontists (AAO) — patient FAQs — aligner wear requirements (“at least 22 hours a day… they can only move teeth when they are in your mouth”), how aligners and attachments work, and appliances and at-home treatment guidance (retainers, DIY warnings, free/low-cost consultations). AAO position on appliance choice, quoted via Orthodontic Practice US.
- AAO — Adult Orthodontics FAQ — aaoinfo.org/faqs/adult-orthodontics: one in four orthodontic patients is an adult; “healthy teeth can be moved at any age”; adult treatment timelines; adult insurance and HSA/FSA notes.
- Peer-reviewed review of clear aligner therapy (PubMed Central, PMID 37881665) — PMC10597356: aligners not recommended for severe crowding/spacing requiring extractions or complex skeletal discrepancies.
- Li et al. — CBCT study of root resorption (PubMed Central) — PMC6943096: resorption prevalence 56.30% (aligners) vs. 82.11% (fixed appliances); mean severity 0.13 ± 0.47 mm vs. 1.12 ± 1.34 mm; 373 roots, 70 subjects, groups matched by ABO discrepancy index.
- Fang et al. — systematic review & meta-analysis — external root resorption significantly lower with clear aligners (SMD −0.65, 95% CI −0.74 to −0.55), 11 studies; and Dentistry Journal (2025) systematic review — MDPI Dentistry Journal 13(12):580: 10 studies, 575 patients, mean follow-up ~22.6 months, mean differences favoring aligners from −0.64 mm to −0.26 mm by incisor type.
- Speech study (Orthodontics & Craniofacial Research, 2023) — repeated-measures study of 40 participants finding both aligners and fixed appliances significantly affected self-perceived speech initially, aligners more so; abstract via Medscape/MEDLINE. Duration of the effect (days to 1–2 weeks) reflects clinical guidance from treating practices.
- SmileDirectClub closure & ADA response — DrBicuspid — “SmileDirectClub's end triggers ADA response”: Chapter 11 (September 2023), worldwide shutdown December 8, 2023, ~2 million customers, ADA statement of December 12, 2023.
- Byte suspension & NY AG recovery — AAO — “A year of direct-to-consumer news”: Byte's voluntary suspension October 24, 2024 in consultation with the FDA; AAO–FDA meeting July 2024; $4.8 million recovered by NY AG Letitia James for 28,000+ consumers (2,265 New Yorkers).
- CDS antitrust suit — DrBicuspid — “ADA, AAO, Align hit with antitrust lawsuit” (December 2024 filing in California Superior Court). Presented on this page as allegations only; no outcome is established.
- Orthodontist vs. general dentist training — SoFi / AAO summaries — orthodontist vs. dentist: shared DDS/DMD, 2–3 year orthodontic residency (~3,700 specialty hours), optional ABO board certification; AAO on specialty status and training (aaoinfo.org: two to three years of residency after dental school).
- Treatment-length ranges — AAO-cited averages (braces 18–24 months, severe cases to 36; aligners 6–18 months for mild–moderate cases) as compiled in orthodontic patient guidance; national cost range $3,000–$8,000 verified against 2026 sources.
Method in one line: every figure on this page traces to a named source above; where the evidence was a marketing claim without a citation (percentage-speed claims), an unsourced statistic (a relapse percentage repeated on dental blogs but not found on any AAO page), or data we could not verify for Tennessee (local ortho pricing), the page says so instead of publishing the number.