IADR Abstract Archives
Volume Loss and Depth Analysis Using Stylus Profiler and Laserscanner
Objectives: To test the hypotheses that (1) a laserscanner used for measuring volume loss will demonstrate the same results as a Dektak profiler; (2) the surface roughness will affect the volume loss measurement of the laserscanner; (3) results from scanning have no more than 10% inter-rater difference.
Methods: Eight 12 x 2 mm disks (Zirpress, Ivoclar Vivadent) were fabricated. Three indentations from fine, medium and rough grit burs (Maxima Diamonds, Henry Schein) were produced using a drill press (PFG 100, Cendres & Metaux, Biel, Switzerland) at 10 rpm on both sides of the disk. All indentations were analyzed using the Dektak stylus profiler (Dektak 150, Veeco). Around 3,500 data points were taken for each depth profile scan, and the accuracy of depth measurement for Dektak was calibrated to 50 nm. The volume loss was calculated by integrating the measured data points around the indentations. The maximum depth for the indentations was identified as the deepest data point of the depth profiling scan. The same disks were scanned using a laserscanner (LAS-20, SD Mechatronik). Volume loss and maximum depth were calculated by three operators. Linear regression analysis was performed to compare values from the laserscanner and Dektak and determine the best fit line. R2 was calculated to assess goodness of fit.
Results: The roughness from different grits were clearly observed using Dektak. The laserscanner was unable to detect differences in roughness or variations with the indentation contours. Therefore, the maximum depths measured with laserscanner were underestimated by 10-15%. For volume loss estimations, a 40-55% underestimation error was obtained with the laserscanner.
Conclusions: While laser scanning is a good tool to measure clinical wear, significant differences in both maximal depth and volume loss were identified using Dektak. There is a need to improve technologies in this area for dental research.
Methods: Eight 12 x 2 mm disks (Zirpress, Ivoclar Vivadent) were fabricated. Three indentations from fine, medium and rough grit burs (Maxima Diamonds, Henry Schein) were produced using a drill press (PFG 100, Cendres & Metaux, Biel, Switzerland) at 10 rpm on both sides of the disk. All indentations were analyzed using the Dektak stylus profiler (Dektak 150, Veeco). Around 3,500 data points were taken for each depth profile scan, and the accuracy of depth measurement for Dektak was calibrated to 50 nm. The volume loss was calculated by integrating the measured data points around the indentations. The maximum depth for the indentations was identified as the deepest data point of the depth profiling scan. The same disks were scanned using a laserscanner (LAS-20, SD Mechatronik). Volume loss and maximum depth were calculated by three operators. Linear regression analysis was performed to compare values from the laserscanner and Dektak and determine the best fit line. R2 was calculated to assess goodness of fit.
Results: The roughness from different grits were clearly observed using Dektak. The laserscanner was unable to detect differences in roughness or variations with the indentation contours. Therefore, the maximum depths measured with laserscanner were underestimated by 10-15%. For volume loss estimations, a 40-55% underestimation error was obtained with the laserscanner.
Conclusions: While laser scanning is a good tool to measure clinical wear, significant differences in both maximal depth and volume loss were identified using Dektak. There is a need to improve technologies in this area for dental research.