Measurements of Dimensional Accuracy Using Linear and Scanning Profile Techniques

Various measurement methods have been described for the determination of dimensional accuracy and stability of denture base materials. This investigation introduces a computerised coordinate measuring machine (CCMM) and compares it with two methods routinely used for assessment of the accuracy of fit of denture base materials. The results demonstrate that the three methods (digital calipers, optical comparator, and CCMM) are acceptable for linear measurement. The CCMM was also used in its scanning mode to define and to quantify the contour changes of the resin bases. The advantages of the CCMM become apparent when two-dimensional changes require assessment.