Effects of the protraction facemask on vertical dimension : A cephalometric study

AIM: To evaluate the skeletal responses to a maxillary protraction facemask on the vertical dimension in Class III patients.
SUBJECTS AND METHODS: Twenty patients (10 males, 10 females, mean age 8 years) with dental and skeletal Class III were analyzed. All the patients were treated with a banded appliance using a facemask with protraction forces exerted by elastics for 14 to 18 hours a day. Standardized lateral cephalograms were obtained before treatment (T1), at the end of treatment (T2), and after an observations period of 1 year (T3). The vertical skeletal relationships were analyzed by angular and linear cephalometric measurements (maxillary inclination SN/SNP-SNA, mandibular inclination SN/Go-Gn, vertical jaw relationship SNP-SNA/Go-Gn, posterior facial height S/Go, anterior facial height N/Me).
RESULTS: Maxillary inclination diminished between T1 and T2 and increased between T2 and T3. The mandibular inclination increased between T1 and T3 (mean 1.7). Vertical jaw relationship increased between T1 and T2 (mean 2.4) and diminished between T2 and T3. The posterior and anterior facial height increased 2 mm and 2-4 mm between T1 and T2, respectively).
CONCLUSIONS: Facemask therapy causes an increase in vertical facial dimensions due to a posterior rotation of the mandible and thus its use is not indicated in high angle cases.