Improving the Color Measurement Process for Denture Teeth to Reduce Color Measurement Errors by Measurement System Analysis

Abstract

The research on the color of teeth or dental restoration materials is an important issue that requires precision and accurate measuring. This study aims to apply measurement system analysis (MSA) to improve the color measurement process of denture teeth. The goal is to reduce measurement errors for inexperienced operators. Two experienced and two inexperienced operators performed color measurements of each denture teeth of the tooth shade guide using the spectrophotometer. The color difference values (DE) were analyzed to assess the repeatability and reproducibility of the measurement system. If the ratio of variance of the measurement system to the total variance (%GR&R) exceeds the acceptable threshold of 30%, it becomes imperative to improve the measurement process. The results of the color difference measurements before improvement revealed a %GR&R of 59%, exceeding the acceptable limit. After the measurement process was improved by setting the position of the denture teeth on a measuring port of the spectrophotometer and providing intensive knowledge to inexperienced operators about the color measurement principles and techniques, along with forewarning, the results showed a reduced %GR&R to 23%. This suggests that MSA can improve the repeatability of measurements by operators or methods, as well as the reproducibility between operators or methods. The improved measurement process can be established as a procedure for inexperienced operators.