A Study of new development and design of the stock tray for edentulous patients

目的：为方便上颌无牙嵴的三维测量，应用三维激光扫描仪对上颌无牙嵴进行三维测量。方法：从我科存档的研究模型中选择140对上颌无牙研究模型（男60对，女80对）。使用三维扫描仪（LPX-250,Roland DG）扫描研究模型。扫描图像可以从任何角度进行数字处理。分析软件允许两点之间的线性距离测量。在上颌的左右Hamuler切迹和下颌骨的左右后磨牙垫中点处建立后参照点。无牙嵴宽度确定为后参考点之间的距离。通过前无牙嵴与参考线的横切面建立前参考点，该参考线以后参考线为中心垂直绘制。结果和讨论：三维激光扫描的持续时间大约为7分钟，从研究病例放置在扫描仪中到数据记录。获得无牙牙脊的宽度和长度的绝对值。测量结果显示，上颌无牙嵴宽度为47.1 mm，下颌骨无牙嵴长度为47.2 mm, 30.9 mm, 56.3 mm。男女数据比较，上颌宽度、长度、下颌骨宽度差异有统计学意义（p<0.05）。但宽度与长度的回归分析无显著相关性（上颌骨r=0.116；下颌骨r=0.239）。这些结果不支持利用宽度和长度的相关性进行无牙脊分类的依据。

I.Objectives :In order to facilitate three-dimensional measurements of maxillary and mandibular edentulous ridge, a three-dimensional laser scanner was applied.II.Methods :From the archived study casts in our department, 140 pairs of maxillary and mandibular edentulous study casts (60 males, 80 females) were selected. Study casts were scanned using a three-dimensional scanner (LPX-250,Roland DG). The scanned image can be digitally manipulated for the evaluation from any angles. The analysis software allows linear distance measurement between two points. The posterior reference points were established at right and left Hamuler notch for maxillae and the mid point of the right and left retro-molar pad for mandibles. The edentulous ridge width was determined as the distance between the posterior reference points. Furthermore, the anterior reference point was established by the cross section between anterior edentulous ridge and a reference line that was perpendicularly drawn from the center the posterior reference line. The length of the edentulous ridge was determined along the perpendicular line.III.Results and Discussion :The duration of a three-dimensional laser scanning was approximately 7 minutes from study case placement in the scanner to data recording. The width and length of the edentulous ridge were provided with absolute values. From our measurements, the width and length of maxillary and mandibular edentulous ridges were 47.1,47.2,30.9,56.3 mm, respectively. When male and female data were compared, the maxillary width and length, as well as mandibular width showed significant differences (p<0.05). However, the regression analysis between the width and length did not show significant correlation (maxilla r=0.116 ; mandible r=0.239). These results did not support the basis for edentulous ridge classification using the correlation between the width and length.