CATEGORY 54 AUSTRALASIAN DENTIST CLINICAL “Change is constant, and so is evolution”. It is critical to embrace the evolutionary process for the betterment of mankind. One such evolution in the present orthodontic era is the introduction of aligners, which are now among the most popular orthodontic treatment alternatives! In 1924, rubber made its debut in orthodontics when Orrin Remensnyder developed the ‘Flex-o-Tite’. He suggested that this appliance could cause minor tooth movements1. Later, Harold Kesling introduced the ‘Tooth Positioner’, in the year 1946 made of vulcanite designed to prevent relapse after the orthodontic treatment2. These innovations laid the groundwork for modern orthodontic tools like aligners. The wise words used by Kesling in his research notes are as follows: “Major tooth movements could be accomplished with a series of positioners by changing the teeth on the setup slightly as treatment progresses. At present, this type of treatment does not seem to be practical. It remains a possibility, however, and the technique for its practical application might be developed in the future.” – H.D. Kesling, 1945 In the year 1959, Dr. Henry Isaac Nahoum developed a clear thermoplastic appliance, using an industrial vacuum former, and named it the “Dental Contour Appliance”, which was intended to cause minor tooth movements. The evolution of a revolution Over the years, many orthodontists have consistently researched the potential of using plastic for orthodontic tooth movement. Sheridan developed a type of clear, polymeric plastic capable of providing retention and enabling minor tooth movements in the year 1994. This was a breakthrough in the aligner industry. Sheridan collaborated with Schwartz to patent this appliance in 1997 and named it ESSIX4. To this day, ESSIX remains a widely used aesthetic retainer in orthodontics. The aligner manufacturing previously included sequential wax setups, which were manual and laborious in their application4. The traditional methods had restricted use in comprehensive orthodontics as they could address only minor dental corrections. Orthodontists are now able to digitally plan the treatment using the software to create and simulate tooth movements precisely. This revolution is made possible through the advent of CAD/ CAM technology and rapid prototyping6-7. It has indeed fastened the fabrication process and also ensured accuracy. The use of 3D printing in rapid prototyping has also enabled the fabrication of aligners in a timely and consistent manner. These developments have converted aligners from a niche solution to a widely used treatment option for both simple and complex cases. Birth of invisalign The story of Zia Chishti and the birth of Invisalign marked a turning point in orthodontics. In the 1990s, Chishti, who had previously been an orthodontic patient, realised that the clear retainers he was using to correct his dental relapse might potentially be used throughout the orthodontic treatment. This made Chishti envision a system of successive aligners that could gradually reposition the teeth using the same principle instead of traditional metal braces8. Zia Christi and Kelsey Wirth, another MBA student and two other orthodontists worked together to transform the vision into reality. They designed a custom-made plastic aligner using CAD technology to facilitate tooth movement. This innovation gave birth to Invisalign (Fig. 1) which has established a strong foothold in the aligner niche. Current perspective of aligners The clear aligners have evolved into a sophisticated Orthodontic technique, which was once considered ineffective or limited. This misconception was cleared with the advancements in technology, wherein now clear aligners are used in a multitude of treatment options, including crowding, spacing, deep bite, and open bite. It is imperative to understand that the success of aligner treatment depends on accurate diagnosis, proper treatment planning, and the clinician’s skill to design the aligner movements, rather than the aligners or the biology per se, as assumed. The key is to acknowledge the fact that the aligner is not just a product but a tool in the hands of skilled clinicians to provide comprehensive care. Leading aligner companies in the market We see an enormous rise in the no. of aligner companies, with a new one booming each day. With the new materials, technology, and treatment philosophies being brought to the table daily, we can be assured that aligners have a bright future. Some of the renowned aligner companies include: u Invisalign (Align Technology): Invisalign provides advanced features like SmartTrack material for better fit and predictability and SmartForce attachments for more complex tooth movements. It is one of the pioneers in the aligner industry and has been in the market for about 25 years. To this day, Invisalign has been credited as the number one aligner system. u Spark Aligners (Ormco): The TruGEN™ material that they use offers better clarity and stain resistance. Spark aligners are said to provide precise control of tooth movements, especially in complex cases. The material is an aesthetic solution with a better finish that focuses on patient comfort. u ClearCorrect: ClearCorrect uses ClearQuartz™, a tri-layer material with an elastomeric middle layer. It focuses on providing a more customizable approach to aligner therapy, with flexible treatment options, including limited (Flex, Mini, One, Two, Three) and unlimited plans. u 3M Clarity Aligners: Clarity aligners were developed by 3M and are known for their durable and nearly invisible design. They offer a versatile system with features for treating mild to Aligners – past, present and future Aligners: historical overview Dr Geoff Hall By Dr Geoffrey Hall, BDSc(Melb) Cert Orth (Uni of Penn) MRACDS(Orth) Specialist Orthodontist Fig 1: Invisalign
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