Short-term skeletal and dental effects of the Xbow appliance as measured on lateral cephalograms.

INTRODUCTION: Our objective was to determine the short-term skeletal and dental effects of the Xbow appliance when compared with an equivalent untreated control group as measured on lateral cephalograms.

METHODS: A prospective sample of 69 consecutive Class II patients treated with only the Xbow appliance was compared with 30 historical Class II untreated controls. Standardized lateral cephalograms were used.

RESULTS: Two patients from the treatment group did not complete treatment. The 2 groups appeared similar at pretreatment with the exception of the positions of the maxillary central incisor (2.9 mm more protruded in Xbow group), the mandibular incisor (1.7 mm more protruded with the Xbow group), and Point A (2.8 mm forward restriction in Xbow group). There were statistically significant differences for 9 of the 14 evaluated cephalometric variables when normal growth changes were factored out. Those differences favoring the Xbow for changes in the direction of Class II correction include SNA, ANB, L1-MP, L1 minus Pg, overjet, U6 minus A, L6 minus Pg, and A-OLp. Meanwhile, the control group showed a statistically significant decrease in the mandibular plane angle compared with the Xbow group.

CONCLUSIONS: Skeletally, a diminution of maxillary protrusion without mandibular advancement and an increase of the vertical dimension were found. Dentally, overjet correction was accomplished by an increase in mandibular incisor protrusion without maxillary incisor movement. The maxillary molars were distalized whereas the mandibular molars were mesialized.