THE HISTORY OF THE EVOLUTION BRACKET
SEVEN STEPS TO PERFECTION

In 1999, after using the self-ligating TIME Bracket for several years, Dr. Hatto Loidl approached Adenta GmbH with the idea to use the same self-ligating clip mechanism for a lingual bracket.One significant new design point was the slot positioning in the upper and lower brackets from 3-3. This design modification allows the arch wire to be inserted from the occlusal plane, ensuring that in deep bite or extraction cases the force will be applied to the metal walls of the slot and not against an elastic ligature. Another very important feature was the self-ligation aspect. With normal lingual brackets an arch wire change is very time consuming and always requires a longer appointment time in an orthodontic practice. With the self-ligating lingual Evolution LT bracket, the arch wire change is even quicker than a wire change using elastics and buccal brackets .After 10 months of design and testing, the first generation of self-ligating lingual brackets were sent to Dr. Hatto Loidl for in-patient treatment trials. After some design and form changes the Evolution LT, 2nd Generation was launched to the market in 2001.The treatment with the Evolution LT bracket was very quick and successful, but after more than 150 cases were finished, we put all the feedback from our customers together and redesigned the Evolution SLT bracket with the following modifications.

1. More torque in the upper and lower anteriors.
2. The original idea to create a thinner customized base, specially for major anatomical differences in the lingual surfaces worked well, but in more than 60% of the crown forms the customized base could be even thinner if the torque was enlarged. This experience leads us to the conclusion that we need a higher base torque for 60% of the patients (average cases), and also a low torque bracket for the anatomical variations
   in crown shapes.
3. We changed the upper centrals and laterals from 45° base torque to 60°.
4. We changed the lower centrals and laterals from 35° base torque to 60°.
5. The low torque bracket still has 40° base torque.
6. Due to the short inter-bracket distance and the position of the lingual bracket, overpowering of the tooth roots can occur. Our spring clip provides about 550 grams of force on the arch wire, which is an equal amount of force to a new elastic ligature. On the other hand, the spring clip is powerful enough to keep an arch wire in the slot. This gave us the idea of introducing the safety release feature in the Evolution SLT bracket. If you apply more than 600 grams of force on the bracket, the spring clip will slowly release the arch wire out of the bracket slot. Due to the deeper slot it is easy to ligate the arch wire in the bracket, because the spring clip will give more space to the arch wire to slide in the bracket slot, especially on rotated teeth.
7. The Evolution SLT, 3rd generation was also optimized in the buccal-lingual dimension as a low profile bracket. The buccal-lingual height is only 2.1mm, which is a lot lower than most brackets currently on the market.