Three-dimensional Accuracy of Resin Block through Various Measurement Methods

Objectives: By three-dimensional (3D) analysis of wear on occlusal splint, sleep bruxism may be evaluated quantitatively. The objectives were to investigate the difference of 3D accuracy of measuring resin blocks between colors, surface preparation agents, and measurement devices.
Methods: Clear (1.014cm*3.009cm*5.008cm) and ivory (0.990cm*2.998cm*4.998cm) rectangular resin blocks, measured by a digital caliper (NTD12-15C/ Mitsutoyo Corp.), were manufactured by Dental CAM (DWX-50/ Roland). After coating the blocks with surface preparation agents (spray (Powder scan spray/ Quest) or powder (Pure scan powder/ VITA)), the bocks were measured 10 times with non-contact type 3D scanners (Arctica/ KaVo or Identica/ MEDIT). The vertical, horizontal, and height dimensions of each scan data were measured five times using a 3D scan data evaluation software (GOM Inspect/ GOM). Statistical analyses were done by calculating the mean and standard deviation of each side. Moreover, the average percentage of mean and standard deviation to actual length were calculated as error and variation to the actual length of each scan data. Comparisons between colors (with powder preparation measured by Arctica), surface preparation agents (clear block measured by Arctica), and measurement devices (clear block with powder preparation) were analyzed statistically using a paired t-test.
Results: According to errors to actual length, statistical differences were found between clear and ivory blocks, and between Arctica and Identica. Although, a significant difference between spray and powder surface preparation agents was not found. The variations to actual length were not different by any measurement methods.
Conclusions: When three-dimensionally analyzing wear on occlusal splints made of resin, consideration of resin color and 3D scanner has been found to be important.