Treatment of: Class II Div. I -
Extraction of Upper 1st and Lower 2nd Premolars
Aligning - Cont’d
Titanium in .022 slot brackets). This is due to the activity of the spring clip that occurs when the wire diameter fills the
passive zone of the bracket, and just engages the clip. Passive self-ligating brackets require wires that are full sized in the
labio-lingual dimension to fully resolve rotations. This results in higher forces and less comfort for the patient. Any wire
less than full dimension will lack the control necessary to fully resolve the rotations with a Passive self-ligating appliance.
Leveling and Control of Torque
After 30 weeks of treatment, leveling and torque control were initiated with 0.018 x 0.018 D Wire in Nickel Titanium.
The D shaped archwire allows the occlusal and gingival slot walls to be engaged by the archwire, thus initiating torque
control, while the rounded labial surface of the archwire only minimally deflects the spring clip. This lessens friction, and
allows continued movement with relatively light forces. Twenty weeks later, 0.017 x 0.022 SPEED Wire in Nickel Titanium
were placed to finalize torque correction, and idealize archform. After an additional 12 weeks, 0.018 x 0.018 D Wire in
stainless steel with reverse curve of Spee was placed in the lower arch to finish bite opening. Fully opening the bite is
necessary prior to the retraction of the upper incisors to prevent incisor interferences on the lower brackets, and the loss of
maxillary molar anchorage that then occurs. We generally place lower stainless steel wires (with reverse Curve of Spee as
needed) prior to the placement of upper stainless steel wires, and the initiation of interarch mechanics.
Bracket Repositioning
Near the end of the leveling phase of treatment, it is possible to evaluate meticulously for bracket placement errors. A
progress panorex is taken, and the patient is carefully evaluated for ANY bracket placement errors. This includes marginal
ridge discrepancies in the posterior teeth, rotation error on any teeth, and axial inclination errors-especially of the anterior
teeth. These are carefully noted and the brackets repositioned while the patient is still in Nickel Titanium archwires. The
teeth are then allowed to continue alignment prior to the placement of stainless steel archwires.
Space Consolidation
Space consolidation was initiated in the upper arch using a 0.018 x 0.018 x 0.018 Hills Dual Geometry Wire. This wire
fully fills the slot in the anterior brackets, thus preventing torque loss during retraction, while the 0.018 round posterior
section reduces friction during space closure. Nickel Titanium springs, elastic modules, or elastic chain can be used to
close spaces, but the forces should be kept light (100-150g) to avoid overpowering the spring clip and causing loss of
torque. In the case of the .018 slot appliance, archwire bowing can also occur if retraction forces are too high. The Hills Dual
Geometry Wire was left in place for 5 ½ months, and bends were placed to extrude the upper second premolars to improve
the interdigitation of these teeth. In this case, extraction spaces were closed approx. 75% within the first six of months of
treatment. Final space closure on Hills Dual Geometry Wire was completed with the use of elastic chain.
Finishing
While space consolidation was occurring in the upper arch, a 0.017 x 0.022 stainless steel SPEED Wire was placed in the
lower arch. It was left in place in the lower arch for the final 5 months of treatment with no adjustments or finishing bends
necessary (note that some bracket positions were corrected during treatment). Ideal alignment, contact relationships, and
marginal ridge alignment are evident 8 weeks prior to the removal of the braces. The upper arch was finished by using a
0.017 x 0.022 SPEED Wire in stainless steel, with duplicated finishing bends that had initially been placed in the 0.018 round
section of the Hills Dual Geometry Wire.
Active treatment was completed in 24 months, and an upper Circumferential Wraparound Hawley was delivered for the
upper arch, while a lower bonded 3x3 was placed. The patient was referred for CSF procedures on the upper incisors to
help assure long term stability. Full time wear was recommended for the first 3 months, to be followed by night time wear
indefinitely.
Post Retention
The patient stopped wearing her upper Hawley only 4 months after the removal of the fixed appliances. Rotational relapse
of 12 was evident 2 years, 3 months later. This was corrected in 2 ½ months with a spring Hawley worn full time. The
patient is currently wearing the Hawley retainer night time only.
