The Evolution of the Spring Aligner for Treating Orthodontic Relapse and Mild Crowding
Spring Aligners or Spring Retainers have been used for minor tooth movement for the past 25 years or more. The original design was developed for very minor tooth movement and mostly for rotations. All spring aligners are fabricated on casts in which model surgery has been performed. The anterior teeth needing correction have been removed and reset in an ideal position in wax on the working cast. The appliance is then fabricated on the corrected cast so that when worn by the patient the “built in” forces correct the misaligned teeth.
The first spring retainers were Hawley retainers with labial acrylic fabricated on the corrected working models.
The first Spring Aligners were Mini Postioners or cuspid to cuspid spring retainers. With the addition of lingual ball clasps the fear of swallowing or aspirating the appliance was reduced.
Adding loops or helixes to the lingual and labial components, often called a Super Spring Retainer was developed to allow a more aggressive correction of the misaligned teeth.
This design flexed more or “opened up more” so that the appliance would be able to be fitted even with a greater correction of the misaligned teeth. These designs had a separate labial and lingual element.
Other advances included using more flexible wires such as TMA and eliminating the acrylic such as the Apex Aligner.
All spring aligners will function and correct misaligned teeth if appropriate case consideration and realistic expectations are adhered to.
Two problems are associated with the past designs: First, stainless steel wires providing the skeleton of the appliances, do not have very much flex or spring significantly. This
effects how much correction can be accomplished. Stainless steel also exerts an abrupt and uncomfortable force. Secondly, the direction of force created by standard spring aligners creates seating and retention problems. The lingual component can have a mouse trap-like, dislodging effect. Standard Spring Retainers are designed for minor correction only and tend to just tip teeth into a better position.
Inman Orthodontic laboratory in Coral Springs FL felt there had to be a better way to realign teeth. They wanted to be able to correct anterior teeth more aggressively with just one appliance that was both effective and tolerable for the patient.
The standard appliance consists of both lingual and labial NiTi driven components. The forces combine to “squeeze” teeth into alignment.
A more extreme case selection may also show success, but only in a very compliant patient. The treatment time depicted below was 5 months.
Another variation of the Inman aligner is the Lingual NiTi driven component that has an adjustment free fixed labial bow. Indications for this design include lingually displaced teeth.
Inman Orthodontic Laboratory has created an appliance that takes advantage of the gentle steady forces of Nickel Titanium by designing piston like components driven by NiTi coil springs (2). The forces are adjusted by altering the coil size and or compressing the coil to create a stronger force.
Secondly, Inman have designed lingual and labial components to function or move parallel to the occlusion, eliminating the mousetrap de-seating forces and allowing true bodily movement of teeth.
A Lingual NiTi driven component, with posterior bite pads, may be employed to open the bite and allow the anteriors to jump. This appliance eliminates the need for finger springs, screws and adjustments.
In cases of tongue thrust or digit sucking a labial NiTi component can be used in conjunction with a habit crib or roller. As the habit is broken the labial component gently guides the anterior back in and down.
Lingual and labial NiTi driven components may also be incorporated in a fixed banded version when patient compliance is an issue.
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