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Orthodontic treatment changes of chin position in Class II Division 1 patients.
Am J Orthod Dentofacial Orthop. 2006 Dec; 130(6):732-41.AJ

Abstract

INTRODUCTION

Because most patients with skeletal Class II malocclusions also have mandibular deficiencies, treatment plans should include improvement in chin projection. On that basis, the purposes of this study were to (1) determine how Class II treatment affects anteroposterior (AP) chin position in growing subjects and (2) ascertain the most important determinants of AP chin position.

METHODS

Pretreatment and posttreatment lateral cephalograms of 67 treated patients (25 extraction headgear and Class II elastics, 23 nonextraction headgear, and 19 Herbst) were collected, traced, and digitized. The average pretreatment age was 12.2 years (range, 9-14 years), and the average treatment duration was 30.2 months (range, 17-65 months). Cephalometric changes were compared with 29 matched untreated Class II controls. Mandibular superimpositions were used to evaluate condylar growth and true mandibular rotation.

RESULTS

All 3 treatment methods produced normal dental relationships and restricted or inhibited AP maxillary growth, with no significant improvement of AP chin position. Differences between changes in vertical position of the maxilla, maxillary and mandibular molars, and condylar growth could not reliably predict changes in chin position. Analyses demonstrated that true mandibular rotation was the primary determinant of AP chin position. Stepwise multiple regression showed that, combined with true mandibular rotation, condylar growth and movements of the glenoid fossa accounted for 81% of the variation in AP changes of pogonion.

CONCLUSIONS

Contemporary treatments do not adequately address mandibular deficiencies. Future treatments must incorporate true mandibular rotation into Class II skeletal correction.

Authors+Show Affiliations

Baylor College of Dentistry, Dallas, TX 75246, USA.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

17169735

Citation

LaHaye, Mark B., et al. "Orthodontic Treatment Changes of Chin Position in Class II Division 1 Patients." American Journal of Orthodontics and Dentofacial Orthopedics : Official Publication of the American Association of Orthodontists, Its Constituent Societies, and the American Board of Orthodontics, vol. 130, no. 6, 2006, pp. 732-41.
LaHaye MB, Buschang PH, Alexander RG, et al. Orthodontic treatment changes of chin position in Class II Division 1 patients. Am J Orthod Dentofacial Orthop. 2006;130(6):732-41.
LaHaye, M. B., Buschang, P. H., Alexander, R. G., & Boley, J. C. (2006). Orthodontic treatment changes of chin position in Class II Division 1 patients. American Journal of Orthodontics and Dentofacial Orthopedics : Official Publication of the American Association of Orthodontists, Its Constituent Societies, and the American Board of Orthodontics, 130(6), 732-41.
LaHaye MB, et al. Orthodontic Treatment Changes of Chin Position in Class II Division 1 Patients. Am J Orthod Dentofacial Orthop. 2006;130(6):732-41. PubMed PMID: 17169735.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Orthodontic treatment changes of chin position in Class II Division 1 patients. AU - LaHaye,Mark B, AU - Buschang,Peter H, AU - Alexander,R G Wick, AU - Boley,Jim C, PY - 2004/11/11/received PY - 2005/01/28/revised PY - 2005/02/15/accepted PY - 2006/12/16/pubmed PY - 2007/1/12/medline PY - 2006/12/16/entrez SP - 732 EP - 41 JF - American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics JO - Am J Orthod Dentofacial Orthop VL - 130 IS - 6 N2 - INTRODUCTION: Because most patients with skeletal Class II malocclusions also have mandibular deficiencies, treatment plans should include improvement in chin projection. On that basis, the purposes of this study were to (1) determine how Class II treatment affects anteroposterior (AP) chin position in growing subjects and (2) ascertain the most important determinants of AP chin position. METHODS: Pretreatment and posttreatment lateral cephalograms of 67 treated patients (25 extraction headgear and Class II elastics, 23 nonextraction headgear, and 19 Herbst) were collected, traced, and digitized. The average pretreatment age was 12.2 years (range, 9-14 years), and the average treatment duration was 30.2 months (range, 17-65 months). Cephalometric changes were compared with 29 matched untreated Class II controls. Mandibular superimpositions were used to evaluate condylar growth and true mandibular rotation. RESULTS: All 3 treatment methods produced normal dental relationships and restricted or inhibited AP maxillary growth, with no significant improvement of AP chin position. Differences between changes in vertical position of the maxilla, maxillary and mandibular molars, and condylar growth could not reliably predict changes in chin position. Analyses demonstrated that true mandibular rotation was the primary determinant of AP chin position. Stepwise multiple regression showed that, combined with true mandibular rotation, condylar growth and movements of the glenoid fossa accounted for 81% of the variation in AP changes of pogonion. CONCLUSIONS: Contemporary treatments do not adequately address mandibular deficiencies. Future treatments must incorporate true mandibular rotation into Class II skeletal correction. SN - 1097-6752 UR - https://www.unboundmedicine.com/medline/citation/17169735/Orthodontic_treatment_changes_of_chin_position_in_Class_II_Division_1_patients_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0889-5406(06)01026-2 DB - PRIME DP - Unbound Medicine ER -