Comparison of a three dimensional laser scanner with coordinate measuring machine in arch drawing

Background and aim: The aim of present study was to compare the ۴th degree polynomials’ drawings generated by the invented laser scanner and ones generated by a CMM. Materials and methods: This diagnostic experimental study was conducted on maxillary and mandibular orthodontic study casts of ۱۸ adults with normal Class I occlusion. First, coordinates of the points on all casts were measured by a CMM. Then, three-dimensional coordinates (X, Y, Z) of the points on the same casts were measured by a ۳-D laser scanner designed in Shahid Beheshti University, Tehran.The validity and reliability of each of the systems were assessed by means of Intraclass Correlation Coefficient (ICC) and the root mean square(RMS). Results: The mean RMS for CBPs obtained from CMM and the fitted polynomial for upper and lower dental models was ۰.۸۸۵. The mean RMS for these CBPs on the custom defined polynomial obtained from the laser scanner was ۰.۹۱۱. The mean correlation coefficient for CBPs obtained from CMM and the fitted polynomial for upper and lower dental models was ۰.۹۹۶. The mean correlation coefficient for these CBPs on the custom defined polynomial obtained from the laser scanner was ۰.۹۹۴.Conclusion: The invented laser scanner is nearly as accurate as a CMM in providing an arch form drawing by recording of CBPs on the teeth and use of a ۴th degree polynomial fitted to them.