Main Instructor Eric Jein-Wein Liou
Department / Institution Department of Orthodontics, Chang Gung Memorial Hospital, Taipei branch, Taiwan
Classification Case report
Mandibular growth affects the treatment results in Class III growing patients. An innovative technique for the control of mandibular growth in a Class III growing patient will be presented.
An 11-year-old girl with a concave profile, anterior crossbite, inadequate smile arc, maxillary hypoplasia, & mandibular prognathism will be reported. She was treated with maxillary orthopedic protraction & redirection of mandibular growth. The maxillary orthopedic protraction was completed in 3 months with a double-hinged expander, Alt-RAMEC, & a pair of intraoral protraction springs. The mandibular growth was then redirected through bimaxillary total arch extrusion by incremental increase of bite raisers on the upper posterior teeth & bilateral intermaxillary box elastics. The treatment time was 2.5 years, & the results were evaluated by superimpositions of the CBCT images taken before & after treatment. The maxilla grew 3.1 mm at the frontonasal processes of maxilla, & the mandibular condyles grew 9.2 mm during the treatment. The total arch extrusion was 4.6-6.4 mm in the maxilla & 3.7-5.2 mm in the mandible, & the mandible was redirected to grow downward 12.0 mm but forward 0.0 mm. The facial profile & smile arc were improved without lip incompetence.
(3) 「Discussion and Summary」
Downward redirection of mandibular growth by bimaxillary total arch extrusion could be an effective technique for the control of mandibular growth direction in growing patients with Class III malocclusion.
Control of Mandibular Growth Subsequent to Maxillary Orthopedic Protraction in A Growing Patient with Class III Malocclusion