History of Clear Aligners: An Interesting Journey Into The Past And A Fascinating Vision Of The Future Of Ortho-care.

Written by Dr. Kritika Laddha | Medically Reviewed by Dr. Zein El Hammouz, DDS, MFD/RCSI.


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Table of Contents
1. History of clear aligners
2. Evolution of Invisible Aligners 
3. Future of Orthodontics
4. The Evolution of the Business Model


 


Clear aligner technology has evolved drastically in the last two decades. Although clear aligners seem relatively new, the concept of using removable appliances to move and correctly position teeth dates back to the 1940s. The aligners themselves have been modified extensively to increase the efficacy of tooth movements (1).


 


History of Clear Aligners 


Several historical breakthroughs paved the way for the modern technology we use in orthodontics today. Here is a brief history:


1945: Kesling And His Tooth Positioner


In 1945, Herald Dean Kesling designed a simple device to guide teeth into their ideal positions (2,3). The tooth positioner  device intended to correct mild discrepancies. It was an active orthodontic appliance used in the finishing and retention phases. Even today, its modern version is available at TP orthodontics, Inc, a company founded by Kesling. 


 


1971: Ponitz Invisible Retainers


Robert John Pointz developed a clear plastic appliance in 1971 for the retention of orthodontic cases. He proposed that the tooth can be moved or repositioned using the appliance. The main advantage of Ponitz’ invisible retainer is the ease of fabrication, insertion, and minimum chair side adjustments of the appliance. They were used for bruxism cases and as splints for trauma cases. (2)


 


1986: "Houston, Do You Copy?" How Nasa Gave The First Step For Clear Aligners Creation


NASA's Advanced Ceramic Research worked with Ceradyne Inc. to develop polycrystalline alumina (TPA). The material is strong, smooth, and transparent and was initially used to make infrared antennae in missile trackers. In 1986, Unitek contacted them when searching for a transparent material for orthodontic treatment. Ultimately, in 1987, Ceradyne and Unitek worked together and developed the first invisible braces (14).


 


1990's: The Worldwide Clear Aligners Revolution


This decade changed the future of orthodontics and brought us the clear aligners we know today. In 1993, John Sheridan developed an Essix aligner system for tooth movement(4). Later, in 1997, two Stanford University students, Kelsey Wirth and Zia Chishti introduced clear aligners named Invisalign (5). They combined aligner therapy with 3D imaging technology, which removed the tedious process of manual fabrication. 


 


Evolution Of Invisible Aligners: Present-Day Aligners


The current clear aligner system combines the principles put forward by Kesling, and others with modern CAD/CAM technology. Here's what present-day clear aligners look like: 


Material Used


Aligners are made of transparent, thermoplastic material and customized to the patient's dental arches. Other materials used in invisible aligners include 


  • Polypropylene, 
  • Polycarbonate, 
  • Thermoplastic polyurethanes, and 
  • Ethylene-vinyl acetate(6).


Image
tri-layer construction for eon aligner
Trilayer material construction


Gingival Margin Design


Clear aligners should completely seat on insertion. They should not dislodge or lift vertically. The possible margin designs are scalloped, straight cut at the gingival zenith, and straight cut 2 mm above the gingival line(7).


 


Image
straight trimline vs. scalloped trimline
Straight vs Scalloped Trimlines


 


Techniques


Clear aligner therapy works on the principle of-


  • Using push forces to move the tooth through small increments. This can be achieved with the help of auxiliaries like attachments, elastics, TADs, etc.


A common question is: How much pressure should be applied to move the tooth? We apply forces in predictable rates and amounts depending upon the tooth shape, size, periodontal conditions, and the type of movement required.


Auxiliaries


In the beginning, aligners used a displacement-driven system with no auxiliaries. Later, auxiliaries were used to enhance the efficacy of orthodontic tooth movements. These included attachments, intermaxillary elastics, and buttons.  These help achieve more complicated  challenging movements, and increase the predictability of the movements including bodily movements, extrusion, rotations(9).


 


Clear Aligners Treatment Process


Tooth movements that can be achieved through clear aligners include :


  • Rotation, 
  • Expansion, 
  • Protrusion, and  proclination 
  • Buccolingual tipping of incisors (8). 
  • Mesiodistal bodily  movements 
  • Intrusion and extrusion
  • Retraction and constriction 


 


To ensure optimal tooth movements, patients should wear aligners for a minimum of 22 hours a day for 1 or 2 weeks (depending on the case) (11).


The Future of Orthodontics: Artificial Intelligence 


Clear aligners have undergone continuous development over the years. Modern-day clear aligners use the latest technology, including the following:


Intraoral Scanners and CAD/CAM Technology


3D intraoral scanners are a more accurate and faster way of  recording the patient's teeth. There’s a lesser chance of a redo being required. The records can also be transferred instantly with just one click.  


Intraoral scanners are particularly useful in patients with gagging and anxiety issues. These records are interpreted by CAD (Computer-Aided Design) and the aligner sheets are thermoformed on 3D printed models.


Image
brunette women getting her teeth scanned by a doctor
3D Scanning


3D Printing: 


Aligners manufactured on 3D printed models offer many advantages They are accurate, easy and fast  to fabricate with few refinements required


An intraoral scanner creates digital models of the teeth, which are then 3D printed using 3D printing machines. Later, clear thermoplastic sheets are thermoformed on top of the model to create the aligners. (12). 


CBCT


CBCT, a software that is driven by artificial Intelligence (AI), can boost treatment efficacy and reduce the number of refinements required. It helps dentists treat patients with precision and accuracy. 


Using CBCT Analysis, they can look at the roots of teeth and the surrounding bones and create a 3D model with minute details (13). This helps doctors analyze the patient's condition and prepare a suitable treatment plan. Doctors can also achieve more predictable outcomes by tracking teeth movements during the treatment. 


 


Image
an image of a cbct on a screen
CBCT Scan


 


The Evolution of the Business Model 


Since the introduction of clear aligners, their market has grown exponentially. As per the Fortune Business Insights report, the global market for clear aligners is $ 2.41 billion in 2020 and is expected to reach $10.04 billion in 2028 at a compound annual growth rate (CAGR) of 19.7% in the forecast period, 2021-2028. 


With continuous evolution in the clear aligner technology and dentistry, many business models have been developed by the manufacturers, including:


  • Doctor-led Model: It has dominated the market under which the treatment is offered at the doctor’s clinic whereas the treatment planning and aligner production is performed by the clear aligner manufacturer. Direct-to-consumer (D2C): The model is designed to reduce treatment costs for the consumers and improve its accessibility. In this, cases are evaluated in the customer’s home or at the company’s location. 


  • Telehealth: In this model, doctors supervise the treatment remotely.  
  • In-House Aligners: In this business model, Dentists accept and evaluate a case, plan the treatment, and print aligners on the same day using 3D printers. It cuts costs and delays. 


A slightly modified model is also gaining momentum where the dentist determines a treatment plan and orders the fabrication of aligners from an orthodontic laboratory.


Conclusion


The evolution of clear aligner therapy has revolutionized orthodontic treatment.It helped dentists deliver higher quality and customized aligners aimed at patients. 


At Eon Aligner, we empower dentists to offer clear aligner treatments using the latest technology. Eon Access, our advanced case management software, features a user-friendly experience that puts dentists in touch with our specialist team of clinicians and experts. 


Eon Aligners are made up of medical-grade material with a 3-layer material construction. It is made by precise aligner design with the aid of high-resolution 3D  printers. The smooth contours with precision deliver constant forces on teeth gently. Through Eon Academy, our doctor e-learning platform, we provide continuous education, clinical training, and support every step of the way. 



 Fill in the form to become an Eon Aligner provider and take your orthodontic practice to the next level.

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FAQ's

When were clear aligners invented?

The development of clear aligners started in 1945 with kesling’s “tooth positioner.” However, modern-day clear aligners were officially introduced to the market in 1999 as Invisalign, by two Stanford University students, Kelsey Wirth and Zia Chishti  (5).

When did invisible aligners come out? 

Invisible aligners were developed in 1997 by  Kelsey Wirth and Zia Chishti. It was approved by the FDA in 1998 and started commercial operations in 1999 (5).

How have aligners changed over the years?

Aligners have evolved rapidly in the last two decades. The technology has evolved, and the average treatment length has also changed. Doctors can now achieve faster and more accurate results using intraoral scanners, CAD/CAM, 3D printing technology, etc. 

What are aligners made of? 

Clear aligners are made of thermoplastic polyurethane/copolyester, polypropylene,b polycarbonate, and ethylene-vinyl acetate (6).

Who introduced CBCT in dentistry?

Cone-beam computed tomography (CBCT) was invented by Sir Godfrey N. Hounsfield in 1967. It was introduced in the dental market of the United States in 2001 (15).

 

References

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2.Oral Health Group. (2020). A Historical Overview of Clear Aligner Therapy The Evolution of Clear Aligners. [online] Available at: https://www.oralhealthgroup.com/features/an-historical-overview-of-clear-aligner-therapy-the-evolution-of-clear-aligners/ .

3.Lee, J.-W., Lee, S.-J., Lee, C.-K. and Kim, B.-O. (2011). Orthodontic treatment for maxillary anterior pathologic tooth migration by periodontitis using clear aligner. Journal of Periodontal & Implant Science, 41(1), p.44. doi:10.5051/jpis.2011.41.1.44 Article 

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8.Tamer, İ., Öztaş, E. and Marşan, G. (2019). Orthodontic Treatment with Clear Aligners and The Scientific Reality Behind Their Marketing: A Literature Review. Turkish Journal of Orthodontics, [online] 32(4), pp.241–246. doi:10.5152/TurkJOrthod.2019.18083 Article 

9.Drake, C.T., McGorray, S.P., Dolce, C., Nair, M. and Wheeler, T.T. (2012). Orthodontic Tooth Movement with Clear Aligners. ISRN Dentistry, 2012, pp.1–7. doi:10.5402/2012/657973 Article

10.Robertson, L., Kaur, H., Fagundes, N.C.F., Romanyk, D., Major, P. and Flores Mir, C. (2020). Effectiveness of clear aligner therapy for orthodontic treatment: A systematic review. Orthodontics & Craniofacial Research, 23(2), pp.133–142. doi:10.1111/ocr.12353 Article.

11.Al-Nadawi, M., Kravitz, N.D., Hansa, I., Makki, L., Ferguson, D.J. and Vaid, N.R. (2020). Effect of clear aligner wear protocol on the efficacy of tooth movement: The Angle Orthodontist, 91(2), pp.157–163. doi:10.2319/071520-630.1.Article

12.Jindal, P., Juneja, M., Siena, F.L., Bajaj, D. and Breedon, P. (2019). Mechanical and geometric properties of thermoformed and 3D printed clear dental aligners. American Journal of Orthodontics and Dentofacial Orthopedics, 156(5), pp.694–701. doi:10.1016/j.ajodo.2019.05.012 Article

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