Yassaei S, Ezoddini-Ardakani F, Ostovar N
Department of Orthodontics, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
Indian J Dent Res. 2010 Oct-Dec;21(4):468-73. doi: 10.4103/0970-9290.74207.
Panoramic radiography is one of the most common techniques for evaluating the jaw bones and associated structures.
The aim of the study was to predict the actual length of the premolar teeth, based on measurements taken on a panoramic radiograph.
This study was done in two stages. In the first stage, the actual and panoramic lengths of 102 teeth of orthodontic patients were measured and compared. In the next stage, the actual and radiographic vertical lengths of four metal balls placed in the molar and first premolar areas of 27 patients, referred to radiography clinic were also analyzed. Comparison of the mean magnification between the two methods was performed by one-sample T-test and P<0.05 was considered as statistically significant.
The total magnification of the premolar region in the vertical plane in the tooth length measurement method was 17.39%, while the same in the metal markers method was 27.39%. The upper teeth showed larger magnification than the lower teeth in the vertical plane. Similarly, the magnification and distortion of the metal markers in the horizontal plane were significantly more than this in the vertical plane and also their magnification and distortion in the molar region were more than this in the premolar region. The actual length of the premolar teeth can be estimated by using a suitable regression formula.
Panoramic radiography can be used for calculating the actual length of premolar teeth.
全景X线片摄影是评估颌骨及相关结构最常用的技术之一。
本研究旨在基于全景X线片上的测量值预测前磨牙的实际长度。
本研究分两个阶段进行。第一阶段，测量并比较了102例正畸患者牙齿的实际长度和全景长度。在下一阶段，还分析了27例前往放射科门诊患者在磨牙区和第一前磨牙区放置的四个金属球的实际垂直长度和X线片垂直长度。通过单样本T检验对两种方法的平均放大率进行比较，P<0.05被认为具有统计学意义。
在牙齿长度测量方法中，前磨牙区垂直平面的总放大率为17.39%，而在金属标记法中为27.39%。垂直平面上，上颌牙齿的放大率高于下颌牙齿。同样，金属标记在水平平面上的放大率和变形明显大于垂直平面，并且它们在磨牙区的放大率和变形大于前磨牙区。可以使用合适的回归公式估计前磨牙的实际长度。
全景X线片摄影可用于计算前磨牙的实际长度。
