Vertical control in Class II hyperdivergent growing patients using miniscrew implants: a pilot study

Abstract

BackgroundThe aim of this study was to determine if miniscrew implants (MSIs) can be used to control vertical development and improve the facial profile of Class II growing hyperdivergent patients. MethodsThe sample includes 18 hyperdivergent patients (12.3±1.8 years of age) who were consecutively treated using MSIs to intrude the maxillary and mandibular molars. They were matched to untreated controls based on age, sex, and the mandibular plane angle. Lateral cephalograms were taken immediately before and after treatment (2.5±0.9 years treatment duration). Growth and treatment changes of 11 linear and angular measurements, as well as the horizontal and vertical movements of 6 landmarks, were described using cranial base, maxillary, and mandibular superimpositions. ResultsThe upper molars of the treated patients were held in place vertically (0.3mm), whereas they erupted significantly in the control group (1.5mm). In contrast, the lower molars erupted significantly more (1.8mm) in the treated patients than control group. The sella-nasion-pogonion and sella-nasion-B angles increased significantly more (0.5° and 0.7°, respectively) in the treated patients than in the control group. Group differences in true rotation (0.4°) were not statistically significant. Individual differences in true rotation showed moderately high negative correlations with the horizontal movements of pogonion (–0.722) and moderately negative correlations with sella-nasion-pogonion (–0.690) and sella-nasion-B (–0.699). ConclusionsTreatment of growing hyperdivergent patients with MSIs successfully controls the vertical and improves facial profile. Greater improvements could have been attained if supraeruption of the lower molar had been better controlled.