Paula Loureiro Cheib1, Lucia Helena Soares Cevidanes2, Antonio Carlos de Oliveira Ruellas3, Lorenzo Franchi2,4, Wagner Fernando Moyses Braga1, Dauro Oliveira1, Bernardo Quiroga Souki1. 1. Department of Orthodontics, Pontifical Catholic University of Minas Gerais School of Dentistry, Bela Horizonte, Brazil. 2. Deparment of Orthodontics and Pediatric Dentistry, University of Michigan School of Dentistry, Ann Arbor, USA. 3. Department of Orthodontics and Pediatric Dentistry, Federal University of Rio de Janeiro School of Dentistry, Rio de Janeiro, Brazil. 4. Deparment of Orthodontics, University of Florence School of Dentistry, Florence, Italy.
Abstract
OBJECTIVE: To test the following two hypotheses regarding the consequences of Herbst appliance (HA) insertion: 1) a significant clockwise mandibular rotation will occur and 2) the displacement of the condyles will follow the same magnitude of the changes of overjet (OJ) and overbite (OB). METHODS: Virtual 3D surface models of 25 patients were generated from cone-beam computed tomographs taken before treatment and immediately after HA insertion. Scans were registered on the cranial base and were analyzed using point-to-point measurements, color-coded maps, and semitransparent overlays. Statistical tests included correlation and simple regression analysis. RESULTS: Pitch rotation, ranging from -2.2° to 2.2° (mean, 0.2°), was observed in clockwise and counterclockwise directions. Condylar sagittal displacement presented a positive correlation with OJ changes. Each millimeter of OJ correction resulted in an anterior condylar displacement of approximately 0.95 mm. Vertical condylar displacement correlated with OB changes and varied mostly between 2 mm and 4.5 mm. CONCLUSION: Immediately after HA insertion, no significant clockwise mandibular rotation was observed. The condyles were displaced anteriorly and inferiorly. Condylar anterior displacement and OJ correction presented a ratio close to 1:1. The vertical displacement of the condyles did not follow the same magnitude of OB changes.
OBJECTIVE: To test the following two hypotheses regarding the consequences of Herbst appliance (HA) insertion: 1) a significant clockwise mandibular rotation will occur and 2) the displacement of the condyles will follow the same magnitude of the changes of overjet (OJ) and overbite (OB). METHODS: Virtual 3D surface models of 25 patients were generated from cone-beam computed tomographs taken before treatment and immediately after HA insertion. Scans were registered on the cranial base and were analyzed using point-to-point measurements, color-coded maps, and semitransparent overlays. Statistical tests included correlation and simple regression analysis. RESULTS: Pitch rotation, ranging from -2.2° to 2.2° (mean, 0.2°), was observed in clockwise and counterclockwise directions. Condylar sagittal displacement presented a positive correlation with OJ changes. Each millimeter of OJ correction resulted in an anterior condylar displacement of approximately 0.95 mm. Vertical condylar displacement correlated with OB changes and varied mostly between 2 mm and 4.5 mm. CONCLUSION: Immediately after HA insertion, no significant clockwise mandibular rotation was observed. The condyles were displaced anteriorly and inferiorly. Condylar anterior displacement and OJ correction presented a ratio close to 1:1. The vertical displacement of the condyles did not follow the same magnitude of OB changes.
Authors: Urban Hägg; A Bakr M Rabie; Margareta Bendeus; Ricky W K Wong; Mang Chek Wey; Xi Du; Jasmine Peng Journal: Am J Orthod Dentofacial Orthop Date: 2008-10 Impact factor: 2.650
Authors: Liliane Rosas Gomes; Marcelo Regis Gomes; João Roberto Gonçalves; Antônio Carlos O Ruellas; Larry M Wolford; Beatriz Paniagua; Erika Benavides; Lúcia Helena Soares Cevidanes Journal: Oral Surg Oral Med Oral Pathol Oral Radiol Date: 2015-10-20
Authors: John C Voudouris; Donald G Woodside; Gurkan Altuna; Mladen M Kuftinec; Gerassimos Angelopoulos; Paul J Bourque Journal: Am J Orthod Dentofacial Orthop Date: 2003-06 Impact factor: 2.650