The Crown bracket system
Accuracy of bracket positioning is essential, so that the built-in features of the bracket system can be fully and efficiently expressed. The Crown bracket has a unique built in system that provides you with 4 visual cues for precise bracket placement.
The Crown Bracket System allows you to utilize each tooth’s visible tooth’s crown to determine exact bracket position. ALL FOUR sides of the Crown bracket base are designed to conform to the shape of a tooth’s crown, allowing the visible surface and the Crown bracket base and its 4 visual cues to determine exact bracket position; this eliminates guesswork and allows the complete visible surface of the tooth to be used easily and quickly for accurate alignment and positioning.
Analysis of Crown forms
Of course, there are a lot of crown forms within the same type of tooth, but it is possible to standardize crown forms. To determine the correct mean crown forms, intact teeth are photographed and all angles, contours and lines are digitized and programed into our engineering graphics program. After extensive evaluation, a standardized crown form based on the principle of a congruent surface, could now be determined with scientific accuracy.
Early diagnosis of problematic tooth forms
The principle of a congruent surface having now be transferred from the tooth's crown to the bracket base, adds an essential advantage in the early recognition of the differences of the crown form and the mean values of the crown. If either secant or the incisal edge is not parallel to the contours of the bracket base, it is easy to detect which crown edge deviates from the norm or has been altered - for instance, by abrasion. This system can now be used to avoid the need for re-bonding while allowing the brackets to achieve their pre-programmed tip for optimum esthetics.
Small in/out for optimum transmission of the prescription
Most brackets are constructed from several separate parts and then soldered together, however this method of manufacturing causes certain design restrictions. Adding a mesh base to a bracket increases the dimension of the in/out, reducing the transmission of the prescription.
Now new state-of-the-art engineering practices in German milling technology, gives us the ability to mill a bracket in one piece, our goal was to reduce the in/out and increase the transmission of the prescription, providing you with more control over movement. One piece milling also provides you with a low profile bracket increasing comfort for your patients.
No separation failures
A one piece bracket also means no separate bracket base and no separate bracket hook, just one complete bracket, adding extra strength and durability and zero chance of separation failures!
Exact torque and angulation values
Milling a bracket in one piece offers yet another advantage, elminating the need to braze separate pieces to the base of the bracket. This brazing method creates the opportunity for brazing errors and incorrect brazing placements of the separate bracket parts. In contrast, a one piece milled bracket does not need to be fixed to a mesh base, hence all brazing tolerances are eliminated, producing a bracket with exact torque and angulation values.
Micro-etched integral bonding base with mechanical undercuts
In order to prevent bonding failures between bracket base and the enamel, we constructed a special test appliance in which two brackets were bonded together. With this test set up we were able to ensure that only the bonding strength of the base was tested. On this computer controlled testing machine, the two brackets were pulled off at a speed of 5 mm/min, the maximum pull off strength was reached shortly before the two bonded brackets separated.
Finally in order to improve the bonding strength one further step, the crown bracket base was also sandblasted to give it a micro-structure. These combination of treatments significantly improved the bonding strength of the crown bracket base, test results were about 20% higher than the results of using a mesh base.
* Seema K. Sharma-Sayal, BSc, DDS, DipOrtho - The influence of orthodontic bracket base design on shear bond strength. University of Toronto, Canada AJO Volume 124
For more information please contact Lorraine Porto at Lorraine@adentausa.com