Initial Bonding:
Tooth numbers 14, 24, 35, 45 were extracted. Three weeks later SPEED Brackets were direct bonded upper 5-5 and lower 4-4. Bands were placed on upper and lower first molars in the event Forsus Springs™ were required later in treatment.
Aligning:
Segmental 0.016 Supercable archwires were placed 3-3 in the upper, and 4-4 in the lower. Supercable was selected due to its extreme flexibility and low force/deflection characteristics. The objective was to align the anterior teeth without taxing anchorage. Due to the low friction environment created through the combination of the .018 slot and an undersized 0.016 Supercable, no retraction force was necessary, thus preserving anchorage. The crowded incisors are able to align because the teeth adjacent to the extraction sites are free to follow the path of least resistance permitting distal movement into the extraction site.
Approximately 7 weeks into treatment, the archwires were changed to 0.014 Heat Activated Nickel Titanium wire, placed molar to molar in both arches. At the time this wire was placed, significant alignment was already evident in both arches, with approximately 1/3 of the extraction space already closed. No loss of anchorage and little/no proclining of the incisors occurred as the teeth aligned. Because no retraction forces were used, little tipping of the upper canines and lower premolars occurred. Initial alignment continued with the placement of 0.016 Nickel Titanium archwires in both arches approximately 7 weeks later.
It should be noted that one of the significant advantages of the SPEED Appliance over any passive self-ligating appliance is that rotation control can be completed in very light wires (0.016 Nickel Titanium in .018 slot brackets, and 0.018 Nickel 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 0.018x0.018 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, 0.017x0.022 SPEED Wire in Nickel Titanium were placed to finalize torque correction, and idealize archform. After an additional 12 weeks, 0.018 x0.018 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 0.017x0.022 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 0.017x0.022 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. |