WEAR DETERMINATION BY USE OF SHADOW-MOIRE

根据ADA接受程序， 复合材料，咬合磨损不应超过250亩 五年的临床服务。 来确定该 磨损量，无论是与标准相比， 使用复杂和昂贵的技术。 弊端 这些技术的缺点是它们要么太不准确， 太复杂而不能被普遍接受。 为了方便 精确的临床磨损测定，至少在几个 在咬合面上的任何一点上， 技术建议与 计算机绘图 这个项目的第一个目标是找到合适的光栅 尺寸，以获得精确，但同时易于阅读 阴影莫尔条纹图。 条纹将记录在 摄影材料和放大。 通过使用数字化仪，x，y， 并且将确定上的不同点的z坐标。 牙齿表面的照片。 通过使用可用的软件 对于坐标转换，这些点将被定向 相对于由所述值确定的参考平面 三个参考点。 这些信息将被视为 用现有的软件来制作计算机图形， 变量，如平面和表面之间的体积 恢复的可能性可以确定。 在最初的技术开发部分之后，研究将 进行，以确定如何因素，如尖点 斜率、尖点长度、摄像机失真以及 放大过程影响阴影的准确性 云纹技术 这些决定将在 已知几何形状的机械加工金属齿模。

According to the ADA acceptance program for posterior composite materials, occlusal wear should not exceed 250 mu during a five year period of clinical service. To determine this amount of wear, either comparison with standards or highly sophisticated and expensive techniques are used. The drawbacks with these techniques are that they are either too inaccurate or too complex to become generally accepted. In order to facilitate precise clinical wear determinations, at least within a few microns at any point on the occlusal surface, a shadow-moire technique is suggested to be evaluated and used together with computerized mapping. The first objective with this project is to find the right grating sizes in order to get precise but at the same time easy to read shadow-moire fringe patterns. The fringes will be recorded on photographic material and enlarged. By use of a digitizer, x-, y-, and z-coordinates will be determined for different points on the photograph of the tooth surface. By use of an available software for coordinate transformation, these points will be oriented relative to a reference plane which is determined from the values of three reference points. This information will then be treated with available software to produce computer graphics, on which variables such as volume between refernce plane and the surface of the restoration can be determined. Following the initial technique developmental section, studies will be conducted in order to determine how factors such as cusp slopes, cusp lengths, camera distortion, and distortion caused by the enlargement process influence the accuracy of the shadow moire technique. These determinations will be conducted on machined metal tooth dies with known geometry.