Original Article
Spee's curve measruement based on least square curve fitting method
Yue Yu, Tianmin Xu
Published 2015-06-20
Cite as Chin J Orthod, 2015, 22(2): 78-82. DOI: 10.3760/cma.j.issn.1674-5760.2015.02.005
Abstract
ObjectiveThe purpose of this study was to put forward a measurement method of Spee's curve on cepholometric radiographs, and measure Spee's curve radius and depth to predict spaces needed for leveling the curve of Spee.
Methods108 orthodontic patients were enrolled in this study. Initial and final cepholometric radiographs were collected. The curve of Spee were painted in image rendering software Adobe Photoshop CS5 (Adobe Systems, Inc, USA ) by using Hanwang LCD digital tracing board (HanWan Technology Co, China). In MATLAB7.0 (MathWorks, USA), the mapped curve of Spee were extracted based on the least square curve fitting methodThe best mathematical model of Spee's curve was validated. On the basis of this research, we measured the curve of Spee's radius and depth.
Results(1) When fitting Spee's curve on cepholometric radiographs through the least square method, circle was the best mathematical model with minimum variance; (2) The same operator had good repeatability and different operators had high consistency in using the Spee's curve measurement method; (3)According to this method, the average spaces needed for leveling full denture Spee's curve on one side was 1.1 ± 0.02 mm, while posterior teeth Spee's curve on one side required an average of 0.87±0.08 mm.
ConclusionsCircle could be used as best mathematical model when fitting Spee's curve on cepholometric radiographs through the least square method. The method in this study could be used to calculate the spaces needed when leveling the curve of Spee.
Key words:
Curve of Spee; Least square method; curve fitting
Contributor Information
Yue Yu
Department of Orthodontics, Peking University, School &
Hospital of Stomatology, Beijing 100081, China
Tianmin Xu