Ladeira Daniela Brait Silva, Cruz Adriana Dibo da, Almeida Solange Maria de, Bóscolo Frab Norberto
Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil.
Braz Dent J. 2010;21(5):458-62. doi: 10.1590/s0103-64402010000500014.
The aim of this study was to determine size, shape and position of the image layer by evaluation of the radiographic image formation in different anatomic positions. A customized phantom was made of a rectangular acrylic plate measuring 14 cm² and 0.3 cm thick, with holes spaced 0.5 cm away and arranged in rows and columns. Each column was separately filled with 0.315 cm diameter metal spheres to acquire panoramic radiographs using the Orthopantomograph OP 100 unit. The customized phantom was placed on the mental support of the device, with its top surface kept parallel to the horizontal plane, and was radiographed at three different heights from the horizontal plane, i.e., the orbital, occlusal and mandibular symphysis levels. The images of the spheres were measured using a digital caliper to locate the image layer. The recorded data were analyzed statistically by the Student'-t test, ANOVA and Tukey' test (?=0.05). When the image size of spheres in horizontal and vertical axes were compared, statistically significant differences (p<0.05) were observed in all areas, portions of the image layer and heights of horizontal plane evaluated. In the middle portion of the image layer, differences in the image size of spheres were observed only along the horizontal axis (p<0.05), whereas no differences were observed along the vertical axis (p>0.05). The methodology used in this determined the precise size, shape and position of the image layer and differences in magnification were observed in both the horizontal and vertical axes.
本研究的目的是通过评估不同解剖位置的X线影像形成来确定影像层的大小、形状和位置。定制了一个体模，由一块14平方厘米、0.3厘米厚的矩形丙烯酸板制成，板上有间隔0.5厘米的孔，呈行列排列。每列分别填充直径为0.315厘米的金属球，使用Orthopantomograph OP 100设备获取全景X线片。将定制体模放置在设备的颏托上，使其顶面与水平面保持平行，并在距水平面三个不同高度（即眶耳平面、咬合平面和下颌联合平面）进行X线摄影。使用数字卡尺测量球体的图像以定位影像层。记录的数据采用Student'-t检验、方差分析和Tukey检验进行统计学分析（α=0.05）。比较球体在水平和垂直轴上的图像大小时，在评估的所有区域、影像层部分和水平面高度均观察到统计学显著差异（p<0.05）。在影像层的中间部分，仅在水平轴上观察到球体图像大小的差异（p<0.05），而在垂直轴上未观察到差异（p>0.05）。本研究中使用的方法确定了影像层的精确大小、形状和位置，并且在水平和垂直轴上均观察到放大率的差异。
