Maxillary “en masse” high-pull traction in Class II division 1 subjects: Which kind of skeletal outcomes does it produce?

Authors:

ABSTRACT

Aim

The aim of the present prospective study was to evaluate if the treatment performed using high-pull traction on a
Stephenson plate had real orthopaedic outcomes in subjects with severe Class II Division 1 malocclusion due to maxillary protrusion.

Methods

Twenty-three growing patients showing Class II Division 1 malocclusion (Stephenson plate group, SPG)
were treated and compared with an untreated Class II control group (CG – 21 subjects selected from the database of Bolton-Brush
Growth Study). Lateral cephalograms at T0 and T1 for both groups were analysed using cephalometric tracing by Jarabak, Pancherz
and Ghosh-Nanda.

Results

Orthopaedic forces were applied in SPG. SPG group showed significantly greater decrease than CG
group of SNA° (-1.4° vs +0.7°), ANB° (-1.3° vs +0°), WITS (-1° vs 0.6°), overjet (-4.1 mm vs +0.3 mm), molar relationships (–6.1° mm vs
-0.1 mm) and upper incisors proclination (1/SpP, -10.3° vs -1°). The maxilla substantially maintained its position (A/OLp +0.3 mm, SNA°
-1.4°) while the mandible slightly grew (Pg/OLp +1.7 mm; SNB° + 0.7°). Facial pattern and AFA/AFP ratio did not change.

Conclusion

The high-pull traction on the Stephenson plate produced more dental than skeletal outcomes in growing subjects,
despite of the application of orthopaedic forces.

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