WEAR DETERMINATION BY USE OF SHADOW-MOIRE

根据 ADA 后路接受计划 复合材料，咬合磨损不应超过250μ 在五年的临床服务期间。 为了确定这一点 磨损量，无论是与标准比较还是高度 使用复杂且昂贵的技术。 缺点 这些技术要么太不准确，要么 太复杂而难以被普遍接受。 为了方便 精确的临床磨损测定，至少在几个范围内 咬合面上任意点的微米级阴影云纹 建议对技术进行评估并与 计算机化测绘。 该项目的首要目标是找到合适的光栅 尺寸以获得精确但同时易于阅读 阴影莫尔条纹图案。 条纹将被记录在 摄影材料并放大。 通过使用数字化仪，x-、y-、 和 z 坐标将由不同点确定 牙齿表面的照片。 通过使用可用的软件 对于坐标变换，这些点将被定向 相对于由值确定的参考平面 三个参考点。 然后该信息将被处理 具有可用的软件来生成计算机图形， 变量，例如参考平面和表面之间的体积 可以确定恢复情况。 在最初的技术开发部分之后，研究将 进行以确定尖点等因素如何 斜率、尖点长度、相机畸变以及由以下原因引起的畸变 放大过程影响阴影的准确性 云纹技术。 这些决定将在 具有已知几何形状的机加工金属齿模。

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.