Thin-plate spline analysis of the effects of face mask treatment in children with maxillary retrognathism.
BACKGROUND
Face mask therapy is indicated for growing patients who suffer from maxillary retrognathia. Most previous studies used conventional cephalometric analysis to evaluate the effects of face mask treatment. Cephalometric analysis has been shown to be insufficient for complex craniofacial configurations. The purpose of this study was to investigate changes in the craniofacial structure of children with maxillary retrognathism following face mask treatment by means of thin-plate spline analysis.


METHODS
Thirty children with skeletal Class III malocclusions who had been treated with face masks were compared with a group of 30 untreated gender-matched, age-matched, observation period-matched, and craniofacial configuration-matched subjects. Average geometries, scaled to an equivalent size, were generated by means of Procrustes analysis. Thin-plate spline analysis was then performed for localization of the shape changes.


RESULTS
Face mask treatment induced a forward displacement of the maxilla, a counterclockwise rotation of the palatal plane, a horizontal compression of the anterior border of the symphysis and the condylar region, and a downward deformation of the menton. The cranial base exhibited a counterclockwise deformation as a whole.


CONCLUSIONS
We conclude that thin-plate spline analysis is a valuable supplement to conventional cephalometric analysis.
School of Dentistry, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC.
Jenny Zwei-Chieng
JZ
Chang
Pao-Hsin
PH
Liu
Yi-Jane
YJ
Chen
Jane Chung-Chen
JC
Yao
Hong-Po
HP
Chang
Chih-Han
CH
Chang
Frank Hsin-Fu
FH
Chang
D016022:Case-Control Studies; D002508:Cephalometry / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D005115:Extraoral Traction Appliances; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D008313:Malocclusion, Angle Class III / Q000628:therapy*; D063173:Retrognathia / Q000628:therapy*