A new system for scanning, measuring and analyzing dental casts based on a 3D holographic sensor.

OBJECTIVES To evaluate the reliability of a new technique for measuring 3D-scanned orthodontic cast models with cross-section planes using teledent, a new software, developed at Technion - for the purpose of this research. EXPERIMENTAL VARIABLE Thirty orthodontic plaster models were divided into three equal groups according to severity of teeth crowding. Measurements of mesio-distal tooth width and the arch length were performed manually on the casts using a conventional caliper. Thereafter, the models were scanned and processed into the software using a 3-D measuring scanner with a holographic sensor 'ConoProbe' (by Optimet, Jerusalem, Israel). teledent used two types of digital measurements; linear and cross-section planes to perform a space analysis on the scanned teeth. Significance was determined by the paired Wilcoxon rank sum test. RESULTS Results show that 3D measurements of tooth width and arch length obtained by cross-section planes were generally similar to manual caliper measurements, while linear measurements were statistically smaller. When comparing space analysis, both digital measurements were statistically smaller than the caliper (p < 0.05). The difference in space analysis between the caliper and the cross-section plane measurements was very small (0.38-0.74 mm) and can be considered clinically acceptable. However, a difference of 1.19-3 mm between the linear measurements and the caliper might have clinical implications especially in severely crowded dentition. CONCLUSIONS This study suggests that measurements performed by cross-section planes are as accurate as the manual caliper and can be employed clinically while the accuracy of linear measurements is sometimes questionable.