The effect of headgear on upper third molars: a retrospective longitudinal study.
OBJECTIVE
To investigate the effects of orthodontic non-extraction treatment with or without headgear on the position of and the space available for upper third molars in growing children with class II malocclusions.


METHODS
The sample consisted of pre- and post-treatment panoramic radiographs and lateral cephalograms of 294 class II orthodontic patients; 160 were treated with headgear and 134 were treated without headgear. The space available for the upper third molar was measured on the lateral cephalogram as the distance from pterygoid vertical (PTV) to the distal surface of the upper first molar crown (PTV-M1). Angulation, vertical position and tooth development stage of the upper third molars were evaluated on panoramic radiographs. All measurements were evaluated statistically.


RESULTS
In both groups PTV-M1 increased, but the increase in PTV-M1 was significantly higher for patients treated without headgear. A linear model for repeated measures revealed that this difference was still significant after correction for age, gender and molar occlusion. Further, there is no evidence that the change in angulation, vertical position and development stage of the upper third molars during orthodontic treatment is influenced by headgear therapy.


CONCLUSIONS
This study indicates that the use of headgear in growing patients significantly affects the space available for upper third molars. However, orthodontic treatment with headgear does not influence the angulation, vertical position and development stage of upper third molars. It is therefore important to always take into account third molars during treatment planning.
Department of Oral Health Sciences-Orthodontics, KU Leuven and Dentistry, University Hospitals Leuven.
Annelie
A
Miclotte
OMFS IMPATH, Department of Imaging & Pathology, Faculty of Medicine, University Leuven & Maxillofacial Surgery, University Hospitals Leuven.
Bieke
B
Grommen
Department of Electrical Engineering, KU Leuven, Belgium.
Steven
S
Lauwereins
Department of Oral Health Sciences-Orthodontics, KU Leuven and Dentistry, University Hospitals Leuven.
Maria
M
Cadenas de Llano-Pérula
Department of Preventive Dental Sciences, College of Dentistry, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia.
Ali
A
Alqerban
Department of Oral Health Sciences-Orthodontics, KU Leuven and Dentistry, University Hospitals Leuven.
Anna
A
Verdonck
Interuniversity Institute for Biostatistics and statistical Bioinformatics, KU Leuven and University Hasselt, Belgium.
Steffen
S
Fieuws
OMFS IMPATH, Department of Imaging & Pathology, Faculty of Medicine, University Leuven & Maxillofacial Surgery, University Hospitals Leuven.
Reinhilde
R
Jacobs
Department of Oral Health Sciences-Orthodontics, KU Leuven and Dentistry, University Hospitals Leuven.
Guy
G
Willems
D000293:Adolescent; D002508:Cephalometry / Q000379:methods; D002648:Child; D005115:Extraoral Traction Appliances; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008312:Malocclusion, Angle Class II / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D008964:Molar, Third / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D015588:Observer Variation; D009805:Odontogenesis / Q000502:physiology; D011862:Radiography, Panoramic / Q000379:methods; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014078:Tooth Eruption