Bionator Balters

Original Article

Long-term Effectiveness and Treatment Timing for Bionator Therapy
Kurt Faltin Jr, DDS, PhD;a Rolf M. Faltin, DDS, MSc, PhD;b Tiziano Baccetti, DDS, PhD;c Lorenzo Franchi, DDS, PhD;c Bruno Ghiozzi, DDS;d James A. McNamara Jr, DDS, PhDe
Abstract: The aim of the present investigation was to provide information about the long-term effects and optimal timing for class-IItreatment with the Bionator appliance. Lateral cephalograms of 23 class-II patients treated with the Bionator were analyzed at three time periods: T1, start of treatment; T2, end of Bionator therapy; and T3, long-term observation (after completion of growth). T3 includes a phase with fixed appliances. The treated sample was divided into two groups according to their skeletal maturity as evaluated by thecervical vertebral maturation (CVM) method. The early-treated group (13 subjects) initiated treatment before the peak in mandibular growth, which occurred after completion of Bionator therapy. The late-treated group (10 subjects) received Bionator treatment during the peak. The T1–T2, T2–T3, and T1–T3 changes in the treated groups were compared with changes in control groups of untreated class-IIsubjects by nonparametric statistics (P .05). The findings of the present study on Bionator therapy followed by fixed appliances indicate that this treatment protocol is more effective and stable when it is performed during the pubertal growth spurt. Optimal timing to start treatment with the Bionator is when a concavity appears at the lower borders of the second and the third cervical vertebrae (CVMSII). In the long term, the amount of significant supplementary elongation of the mandible in subjects treated during the pubertal peak is 5.1 mm more than in the controls, and it is associated with a backward direction of condylar growth. Significant increments in mandibular ramus height also were recorded. (Angle Orthod 2003;73:221–230.) Key Words: Class-II malocclusion; Functional jaworthopedics; Cephalometrics; Cervical vertebral maturation

INTRODUCTION The Balters’ Bionator1,2 is one of the most commonly used appliances for functional treatment of class-II, division
a Chair, Department of Orthodontics, School of Dentistry, University Paulista, Sao Paulo, Brazil; Invited Professor, Department of Fa˜ cial Orthopedics, University of Ulm, Germany. b Associate Professor, Department ofOrthodontics, School of Dentistry, University Paulista, Sao Paulo, Brazil. ˜ c Research Associate, Department of Orthodontics, The University of Florence, Florence, Italy; Thomas M Graber Visiting Scholar, Department of Orthodontics and Pediatric Dentistry, School of Dentistry, The University of Michigan, Ann Arbor, Mich. d PhD program in Pediatrics and Preventive Orthodontics, Department ofOrthodontics, The University of Florence, Florence, Italy. e Thomas M and Doris Graber Endowed Professor of Dentistry, Department of Orthodontics and Pediatric Dentistry, School of Dentistry; Professor of Cell and Developmental Biology, School of Medicine; and Research Scientist, Center for Human Growth and Development, The University of Michigan, Ann Arbor, Mich; Private practice, Ann Arbor, Mich.Corresponding author: Lorenzo Franchi, DDS, PhD, Universita degli ´ Studi di Firenze, Via del Ponte di Mezzo, 46-48, 50127, Firenze, Italy (e-mail: condax@tin.it).

Accepted: November 2002. Submitted: August 2002. 2003 by The EH Angle Education and Research Foundation, Inc.
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1 malocclusions associated with mandibular retrusion. The popularity of this appliance is due in part to a number offavorable characteristics that include the relative ease in the construction and clinical handling of the appliance and the high level of comfort for the patient, who usually shows positive acceptance and compliance. The generic term Bionator, as a matter of fact, describes a ‘‘family’’ of toothborne appliances that produce a forward positioning of the mandible in association with variable effects...