A comparative evaluation of midfacial soft tissue and nasal bone changes with two maxillary protraction protocols: Tooth-borne vs skeletal-anchored facemasks.

Abstract

Greater advancement of the maxilla can be achieved with skeletal-anchored facemasks (SAFM) using miniplates than with conventional tooth-borne facemasks (TBFM). The purpose of this study was to compare the effects of TBFM and SAFM on midfacial soft tissue and nasal bone up to twoyears after treatment. Sixty-seven growing patients with Class III malocclusions were treated with facemasks. They were divided into a SAFM group with 31 subjects (average age 11.1years) and a TBFM group with 36 subjects (average age 11.0years). Cephalometric analysis was conducted using linear and angular midfacial measurements. Lateral cephalograms were taken initially (T0), after treatment (T1) and at twoyears post-treatment (T2). Significance was assessed between the two groups. Comparing changes in the midfacial area between the SAFM and TBFM groups during the traction period (T0-T1), angular measurements such as SNOr (1.34°), nasolabial angle (4.20°), nasal angles 1 and 2 (1.23°, 2.14°) and linear measurements such as Prn, Sn, A' distance (approximately 2mm) increased significantly more in the SAFM group. Over the entire treatment period (T0-T2), the changes in SNOr (1.33°), nasolabial angle (6.54°), nasal angles 1 and 2 (1.45°, 2.99°) and Prn, Sn, A' distance (approximately 2mm) remained significant (P<.05). In the treatment of growing patients with Class III malocclusions with maxillary deficiency, it was possible to achieve significantly greater advancement in the midfacial area with SAFM treatment than with TBFM treatment. This significant difference was well maintained at twoyears post-treatment.