Crozat device
Crozat devices are removable braces for the upper or lower jaw (single jaw devices ) that are completely soldered or welded together from wire. A thick scaffold wire connects the retaining clips. He can carry thinner wires called arms, and these arms can carry even thinner wires called fingers. Originally, Crozat devices consisted of a gold alloy that is superior to silver or non-precious metal alloys, which were later also used, in terms of processing and durability. At that time, Crozat devices were retrofitted and converted so that their precisely machined, square retaining clips only had to be made once. They use the 6s as anchor teeth or, more rarely, the 7s, milk 5s, or additional retaining clips for the premolars. Your short chewing surface pads should stabilize the correct fit of the device without disturbing the bite.
Crozat devices hardly impede remineralization through saliva circulation in the oral cavity. Therefore, they are also unproblematic for long-term orthodontic treatments and can easily remain in the mouth without cleaning when drinking drinks other than water. B. modern correction splints .
history
The Crozat method uses the oldest system of removable braces. George B. Crozat (1894–1966), who practiced in New Orleans, and his German colleague Albert Wiebrecht developed them when fixed band-arch appliances made of precious metals were common in orthodontics and tooth extractions were common for crowding. To do this, they replaced the fastening straps of these braces with retaining clips, as they were already known in dental prosthetics . Primarily, this method, introduced in 1919, made oral hygiene easier for the patient and readjustment for the practitioner. It reduced the risk of tooth root resorptions due to overdosed orthodontic forces and is also suitable for patients with periodontally damaged teeth.
Moreover, watching the user that Crozat appliances to small dental arches with crowding in children and more slowly in adults could develop into a healthy size. This enabled them to avoid orthodontic tooth extractions. In contrast to the orthodontic way of thinking, Crozat based his method on the fact that a healthy chewing organ with a proper tooth position was created in the human being and that teeth could only be overcome by obstacles, e.g. B. lack of space, cross bites, forced guidance or muscular malfunctions, would not find their healthy position. Therefore, his therapy consists in overcoming these obstacles by using small point forces and letting the teeth find their positions. The forces of the tongue, lips and cheek muscles and the clenching have a shaping effect. The Crozat devices should therefore not hinder this, at least in the final treatment phase.
Despite these successes, the Crozat technique remained a niche method because American practitioners were more fascinated by the possibilities of fixed braces, while in Europe the active plates and activators had long been the predominant treatment agent. Wiebrecht developed his technique further and only published a manual about it in 1966. This contributed to the fact that Crozat devices were accepted by German holistic orthodontists as a supplement to the Bionator for adult treatment and preprosthetic orthodontics. Today, however, they are gradually being replaced by newer treatments.
Methodology of the classic Crozat treatment
The original Crozat method shows a single-step procedure, which is also common to many methods with fixed braces. A classic full treatment comprises three stages, of which stages can be omitted in lighter cases: 1. stretching, 2. straightening, 3. arranging teeth and correcting the bite position. To do this, the device is gradually expanded from the basic device via the stretching device to the final device.
- Phase 1:
In addition to stretching by bending the scaffold wire, the basic device can also rotate (derotate) its anchor teeth when it is bent open at an angle. In this phase, the jaw widths must be coordinated.
- Phase 2:
The extensions of the framework wire, which transfer the stretching effect to the premolars, are provided with the wire arms. If necessary, springs for 7 or 8 can be attached to the retaining clips.
With the pair of arms, the incisors can be advanced (protruded), whereby they often stand straighter. Instead, space for constricted canines is gained in the classic way with an asymmetrical pair of arms, the modified arm of which in front of the canine counteracts the pressure that the normal arm exerts against the incisors. While the classic device would need mirror-image new arms if the other canine tooth is also narrowed, it is also possible to work with double arms and additional holding elements on both sides in an unclassical manner, although the development of the jawbone must not be overwhelmed.
If several raised posterior teeth are to be distalized, a lip bumper attached to the Crozat device can absorb additional counterforce from the lip instead of just supporting it on other teeth.
Phase 2 should create space for all teeth, create dental arch congruence and eliminate any forced guidance in order to enable a normal bite position.
- Phase 3:
Finger wires for remaining corrections of posterior teeth are usually left from the retaining clips, and protrusion springs from the arm and body wires, while a labial arch is attached to the outside of the retaining clips for retrusion or derotation. For more targeted work with single tooth springs, e.g. B. to close remaining gaps, a high or low labial arch in arm wire strength can serve as their support instead. As a result, the device remains invisible and the lip forces can better help shape the dental arch.
With the devices, which are also supported on the front teeth, shifts in the bite position can also be achieved if appropriate hooks are attached and rubber bands are stretched between the upper and lower device. This was taken from the fixed treatment technique. With rubber bands on an appropriately equipped Crozat device, however, displaced teeth , which can particularly affect canines , can be pulled into the dental arch if they have been exposed and a hook stuck on.
Overall, the Crozat therapy is a subtle slow treatment for a larger extent. Using their growth, children can be treated more cheaply and more quickly with active plates, because they are not only easier to repair, but also allow more corrections to be made at the same time thanks to their better anchoring in the interdental spaces. z. B. they can simultaneously stretch and stretch using appropriate screw elements, and arrange teeth in available space.
Crozats and plates have a rigid body in common, which is missing from the fixed straight-wire multibracket braces that are widespread today , unless they are added as an annoying fixed additional part of the palatal arch (palatal arch) or lingual arch, or an additional ground plate, a "trainer for braces" or the like . Ä. Is worn.
swell
Old writings by Albert Wiebrecht
Individual evidence
- ↑ Kleinert, M. (2004): The Crozat basic device. Quintessenz Zahntech 30: 764 - 70
- ↑ Kleinert, M. (2006): The Crozat device in the II. And III. Phase. Quintessenz Zahntech 32: 664-70
- ↑ [1] Summary of the Kleinert article
