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Six Month Smiles vs Smilelign

Starting price, treatment length, supervision, FDA safety record and full spec sheet for Six Month Smiles and Smilelign, side by side. Every figure links to the source that states it.

Prices verified Sep 30, 2026FDA records verified Sep 30, 2026
22comparisons with Six Month Smiles
9comparisons with Smilelign

Six Month Smiles (6MS Invisible Aligners, 6MS Relapse Aligners, 6MS Mixed Appliance)·Smilelign (Smilelign)

Six Month Smiles
In-office
Smilelign
In-office
At a glance
Starting price
Provider-setnot published
~£1,000

Blue marks the lower price only where every compared price is quoted the same way (a monthly price in US dollars); prices quoted in another currency, as a one-time fee or as a provider-set range are shown exactly as stated and never converted. Adverse-event figures are raw counts of reports filed with the FDA, not rates (what the reports mean). Each spec value opens that brand's spec sheet, and its numbered sources verify the specs as a set. None of this is a recommendation: the right choice depends on your case, your budget and, above all, an in-person exam by a dentist or orthodontist.

The bottom line

What actually differs

  • Neither is marked lower, since only monthly prices quoted in US dollars are ranked against each other: Six Month Smiles Provider-set and Smilelign ~£1,000.
  • Typical treatment differs: Six Month Smiles 6-10 months and Smilelign 12 months.
Go deeper

Open the full record

Six Month Smiles
  • Prices
  • Treatment length
  • Supervision
  • FDA safety
  • Specs
  • Sources
  • Where to get it
Smilelign
  • Prices
  • Treatment length
  • Supervision
Keep comparing

Every comparison with these brands

Each brand against every other brand on the market. All comparisons

All 22 comparisons with Six Month Smiles

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  • vs Clarity Aligners
  • vs ClearCorrect
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  • vs Dandy Clear Aligners
InvisibleBraces is an informational data platform, not a dentist, an orthodontist, or a seller of aligners. Nothing here is dental or medical advice, a diagnosis, or a recommendation to start, stop, or change any treatment. At-home clear aligners are not right for every case, and moving teeth without an in-person exam carries real risk. Data is aggregated from public sources and each brand's own terms and can be incomplete or out of date. Always consult a licensed dentist or orthodontist and confirm current prices and terms with the provider.
InvisibleBracesInvisibleBraces

The independent, fully-cited comparison of at-home clear aligner brands. Every figure traces to its source. Informational only, not dental or medical advice.

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Typical treatment
6-10 months
12 months
Supervision
In-office
In-office
FDA safety
No recalls
No recalls
FDA adverse-event reports
0
0
Treatment
Treats
CrowdingSpacing and gapsCrossbiteOpen biteDeep biteRelapse after bracesMild to moderate misalignment
Correcting mild-to-moderate crowdingClosing spacing and gapsGeneral cosmetic tooth alignment/straighteningMore complex cases with S4S orthodontic team support
Product lines
6MS Invisible Aligners, 6MS Relapse Aligners, 6MS Mixed Appliance
Smilelign
Wear schedule
Trays changed every 2 weeks; wear hours not published
Each aligner is worn about 22 hours per day and swapped for the next set in the series every 2 weeks, moving teeth roughly 0.3mm per aligner.
Spec sheet
Start method
Taken by the dentist in the practice: an intraoral scan (3Shape, iTero, Cerec or STL files accepted) or PVS impressions, with x-rays and photos; there is no at-home kit.
Digital intraoral scan from any major scanner, or physical dental impressions, taken at the dental practice and sent to S4S in Sheffield
Material
Zendura FLX, a dual-shell material (hard outer shell, elastomeric middle layer), 0.76 mm (0.030 in), per 6MS; the FDA summary describes a thermoformed polyurethane-polyester composite.
Clear thermoformed aligner in a choice of triple-layered material or upgraded Duratain (thinner, stronger, high-clarity, stain-resistant, about 0.8mm); straight-cut or scalloped edge options
Retainers
Not included in the patient tray kit; the dentist orders removable retainers from 6MS after treatment and sets their price
Retention bundle options available as an add-on through the practice
Whitening
Not published
Bundled whitening options available through the practice
Refinements / touch-ups
Up to 2 refinements within 2 years are included in the 6MS Invisible Aligners product (aligner page); a no-charge upgrade to a braces solution is offered to the dentist if braces would produce a better outcome.
2-year free-of-charge refinement period; lab pricing capped at a maximum of 12 aligners regardless of how many are needed, with refinements included
Guarantee
No patient guarantee in the current terms: a limited warranty to the dentist covers defects in material and workmanship, not the outcome
No published patient-facing money-back guarantee; dentist-facing terms include a 2-year FOC refinement period and free replacement aligners
Clinical oversight
In-office: a trained dentist examines, prescribes, fits and monitors; 6MS specialists prepare the plan, overseen by its orthodontists, and the dentist approves it
Dentist-led throughout: the patient's dentist prescribes, provides, and supervises treatment in person, with the S4S orthodontic team available to support complex cases
Financing
Set by each practice
Not published by the brand; any payment plan is arranged by the individual dental practice
HSA / FSA
The brand's cost page says HSA or FSA accounts can help offset the cost; acceptance is the practice's decision
Not applicable (United Kingdom)
Insurance
Some dental plans may cover part of treatment (brand's cost page)
Not published; the patient fee is set by the dental practice
Availability
United States and United Kingdom through trained dentists (the company says its providers are in over 50 countries, without separating braces from aligners)
United Kingdom, available through thousands of UK dental practices
Headquarters
Carrollton, Texas, United States
Sheffield, United Kingdom
Spec sources
  1. 1.6monthsmiles.com
  2. 2.6monthsmiles.com
  3. 3.6monthsmiles.com
  4. 4.6monthsmiles.com
  5. 5.6monthsmiles.com
  6. 6.6monthsmiles.com
  7. 7.6monthsmiles.com
  8. 8.6monthsmiles.com
  9. 9.6monthsmiles.com
  10. 10.6monthsmiles.com
  11. 11.api.fda.gov
  1. 1.smilelign.com
  2. 2.s4sdental.com
  3. 3.s4sdental.com
  4. 4.nw1dentalcare.co.uk
Company
On the market since
2019
2012
Parent company
Xplora USA LLC, doing business as Six Month Smiles, Carrollton, Texas, United States
S4S (UK) Limited (S4S Dental Laboratory), Sheffield, United Kingdom
  • FDA safety
  • Specs
  • Sources
  • Where to get it
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    • All 9 comparisons with Smilelign

    • vs 32Co
    • vs ClearPath
    • vs Dandy Clear Aligners
    • vs Graphy
    • vs Invisalign
    • vs Nuvola
    • vs Six Month Smiles (this page)
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