title: The short-term treatment effects of face mask therapy in Class III patients based on the anchorage device: miniplates vs rapid maxillary expansion.
abstract: OBJECTIVE
  To compare the short-term treatment effects of face mask therapy with miniplates (FM-MP) and face mask therapy with rapid maxillary expansion appliance (FM-RME) in growing Class III malocclusion patients with maxillary hypoplasia.
  
  
  METHODS
  Twenty patients were allocated into two groups according to the anchorage device: FM-MP group (n  =  10; mean age  =  11.2 ± 1.2 years; miniplates in the zygomatic buttress area) and FM-RME group (n  =  10; mean age  =  10.7 ± 1.3 years; bonded or banded RME). The face mask was applied for 12 to 14 hours/day in both groups with a force of 400 g/side directed 30° downward and forward from the occlusal plane. Lateral cephalograms were taken before (T1) and after FM-MP or FM-RME therapy (T2). Skeletodental and soft-tissue variables were measured. Paired and independent t-tests were performed for statistical analysis.
  
  
  RESULTS
  Both groups exhibited significant forward movement of point A and posterior repositioning and opening rotation of the mandible from T2 to T1. The FM-MP group showed significant protraction of orbitale (ΔSNO), and the FM-RME group showed a decrease in overbite and an increase in Björk sum. Comparing the amount of changes between the two groups, the FM-MP group displayed greater forward movement of the maxilla than the FM-RME group (ΔSNA, ΔA to N perp, all P < .05). However, the FM-RME group exhibited a greater opening rotation of the mandible (ΔSNB, Björk sum, all P < .01; ΔPog to N-perp, P < .05) and labioversion of the maxillary incisors (ΔU1-FH, P < .05).
  
  
  CONCLUSIONS
  FM-MP therapy induces a greater advancement of the maxilla, less posterior repositioning and opening rotation of the mandible, and less proclination of the maxillary incisors than FM-RME therapy.
authors.affiliation: Department of Orthodontics, Section of Dentistry, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-Do, Korea.
authors.forename: Nam-Ki
authors.initials: NK
authors.lastname: Lee
authors.forename: Il-Hyung
authors.initials: IH
authors.lastname: Yang
authors.forename: Seung-Hak
authors.initials: SH
authors.lastname: Baek
mesh_terms: D000293:Adolescent; D002508:Cephalometry; D002648:Child; D005115:Extraoral Traction Appliances; D005260:Female; D006801:Humans; D008297:Male; D008313:Malocclusion, Angle Class III / Q000628:therapy*; D008334:Mandible / Q000002:abnormalities*; D008437:Maxilla / Q000002:abnormalities*; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation / Q000379:methods*; D010155:Palatal Expansion Technique / Q000295:instrumentation*; D012189:Retrospective Studies