  Objectives: To assess the effectiveness of digital scanning techniques for
self-assessment and of preparations and restorations in preclinical dental
education when compared to traditional faculty grading. Methods: Forty-four
separate Class I (#30-O), Class II (#30-MO) preparations, and class II amalgam
restorations (#31-MO) were generated respectively under preclinical assessment
setting. Calibrated faculty evaluated the preparations and restorations using a
standard rubric from preclinical operative class. The same teeth were scanned
using Planmeca PlanScan intraoral scanner and graded using the Romexis E4D
Compare Software. Each tooth was compared against a corresponding gold standard
tooth with tolerance intervals ranging from 100{\mu}m to 500{\mu}m. These
scores were compared to traditional faculty grades using a linear mixed model
to estimate the mean differences at 95% confidence interval for each tolerance
level. Results: The average Compare Software grade of Class I preparation at
300{\mu}m tolerance had the smallest mean difference of 1.64 points on a 100
points scale compared to the average faculty grade. Class II preparation at
400{\mu}m tolerance had the smallest mean difference of 0.41 points. Finally,
Class II Restoration at 300{\mu}m tolerance had the smallest mean difference at
0.20 points. Conclusion: In this study, tolerance levels that best correlated
the Compare Software grades with the faculty grades were determined for three
operative procedures: class I preparation, class II preparation and class II
restoration. This Compare Software can be used as a useful adjunct method for
more objective grading. It also can be used by students as a great
self-assessment tool.
