CERAMIC ROTATION BRACKETS
B. Donald McGann, DDS
Abstract
Rotation control has been a particular weakness of plastic and ceramic bracket
products, when compared to their metal counterpart. An appliance and technique
resulting in full or over-correction of rotations on a single patient basis is presented. This
product, combined with the diagnosis of rotations for each case results in a significant
improvement in the clinical efficiency of ceramic brackets.
By indirect bonding a patient specific customized appliance to improve bracket
positioning, archwire compensations for rotation correction can be eliminated. The
traditional ceramic debonding problem is solved by using a custom pad technique for the
indirect bonding.
Since the introduction of plastic brackets and later ceramic, improved esthetics during
orthodontic treatment has been requested by the adult population. Many adolescent girls
also prefer the improved esthetics of clear or tooth colored brackets. Lingual orthodontics
is the ultimate cosmetic solution, but treatment complexity is great, and the cost of
treatment beyond the resources of many patients.
So why are there still metal appliances? Simple, the metal is easier to work with and is
better engineered and manufactured. Better engineering means less wire bending, and
less chair time for the orthodontist. Rotation has been a particular weakness of plastic and
ceramic appliances. (4-7) Full rotation correction has been made possible on an
individual patient diagnosis and appliance application when using the IP Appliance (1).
figure 1: IP Appliance ceramic brackets 5-5 upper and lower with 014 nickel-titanium
archwire. Variable torque and rotations have been applied.
Rotation Capabilities
Improved rotation capabilities can be found with the individual patient, IP
Appliance®* ceramic bracket, by inserting a specially designed “wedge” into the
archwire slot. The wedges are available in 4, 6, and 8 degrees to allow for full or overcorrection of rotations, by simply changing the wedge engaged in the archwire slot. 4Degree rotation has been shown with IP Appliance® metal brackets to fully correct
rotations in the first alignment archwires.
The slot of IP Appliance® ceramic rotation brackets is cut deeper to allow for the
insertion of the specially designed wedge. Different wedges are used for the smaller
lower anterior brackets than other brackets from 5-5, upper and lower, the difference
being the mesial-distal width of the bracket. The removable wedge is inserted into the
slot before engagement of the archwire, maintaining the esthetics of the ceramic bracket.
The end, or tip, of the wedge is positioned into the bracket slot in the direction of the
rotation. Teeth rotated so the facial surface faces the midline are diagnosed as mesial
rotations. The tip of the wedge would be positioned to the mesial. Distal rotated teeth
would have the tip of the wedge positioned to the distal.
Figure2: lateral incisors start with Distal rotations, the facial surface facing away from
the midline. IP Ceramic with 6° wedges in the bracket slot, creating an over-correction
to a mesial rotation.
Figure 3: IP Appliance ceramic rotation wedges are placed into the special deep-cut
slot. Wedges are available in 4, 6, and 8 degrees, with one size for the lower incisors and
another for all other brackets. A 4 degree rotation wedge with the archwire engaged to
correct a “mesial” rotation.
Figure 6: Wedges are removed from the “tree” with a mosquito hemostat and placed into
the slot by holding the edge with a placement instrument as the tab is broken off. The end
of the wedge determines the rotation direction. Mesial rotations are corrected by placing
the end of the wedge towards the mesial during placement.
Rotation Wedge Placement
The rotation wedges are removed from the dispensing tree with a mosquito hemostat
and carried to the bracket slot. The end of the wedge points towards the direction of the
rotation classification. Mesial rotations are corrected by placing the end of the wedge
towards the mesial. The archwire is tied over the top of the wedge to secure the wedge to
the bracket.
Figure 7: Rotation wedges are positioned under the archwire.
Protocol
Initial alignment using 012 or 014 nickel-titanium archwires, in any shape and size, are
first applied without rotation wedges. The smaller gauge archwires may allow the wedge
to “roll” in the slot. Secondary alignment using 18x25 heat activated nickel-titanium (or
016N) in the desired arch shape and size is then applied with 4-degree wedges. The
archwire is cooled and retied during the next 4-6 months, establishing the torque and
archform.
Full correction of rotations is then confirmed by comparing the initial study models to
the alignment result. If any under-corrections still exist, then 6-degree wedges are
applied to these teeth. 8-degree wedges may be used for the over-correction of severe
rotations.
The wedges remain in the slot during the mechanics stage, being replaced only if lost.
After completion of mechanics, a second comparison of the rotations is made using the
initial study models. Wedges are adjusted as necessary to obtain the desired overcorrection or full correction of rotations.
The best appliance for the individual treatment was decided upon, considering the
following features:
1. Rotations: Tooth rotations were classified and prepared for ordering
Treatment started with alignment, using 012 nickel-titanium archwires lower and 014
nickel titanium upper. At 7 weeks, 4° rotation wedges were inserted on the lower
incisors, which were rotated mesial. At 11 weeks, the wedges were changed to 6° at a
wire change to 016 nickel-titanium, medium ovoid archform.
Initial bonding
7 weeks
13 weeks
The wedges remained in the slot as archwires were changed to 19x25 stainless steel for
mechanics. The patient proved to be quite non-compliant, loosing 11 brackets and 4
bands in the 16 months of treatment. The patient forced extra visits at short intervals, 2-3
weeks being typical, and applied double elastic force, thinking this would speed her
treatment. Archwire distortion and excess upper incisor detorquing was the result of
these excessive forces. Our typical scheduled appointment interval is 8-10 weeks.
The patient demanded the appliances be removed at 16 months treatment time, signing
a waiver.
Comparison of study models to show rotation correction
There is a slight over-correction of the lower incisor rotations.
Conclusion
Ceramic bracket rotation control has been less functional than using metal appliances.
Individual patient diagnosis of upper and lower tooth rotations allows the selection of a
ceramic bracket with pre-manufactured features to improve treatment results and clinical
efficiency. Such an appliance significantly removes the need for bracket repositioning
and placing archwire compensations, reducing the amount of doctor time required for
ceramic bracket treatment.
Indirect bonding of the ceramic bracket with custom pads has eliminated the problem
of ceramic debonding, at the same time improving bracket positioning. This new system
should renew your interest in the cosmetic bracket treatment option.
*IP Appliance is a registered trademark of Individual Orthodontics, 1701 East Edinger,
suite C1, Santa Ana, CA 92705. 1-800-737-0720
**IPSoft is a trademark used by Progressive America, Inc. 1701 East Edinger, suite C1,
Santa Ana, CA 92705
***Transbond XT, Sondhi Rapid Set , and Clarity are trademarks used by 3M
Unitek, 2724 S. Peck Road, Monrovia, CA 91016
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