Title: 0508 - Evaluating a Novel Virtual Measuring Technique for 3D-Fit of Restorations


Edward Chien (Presenter)
Henry M. Goldman School of Dental Medicine, Boston University

Yuwei Fan, Henry M. Goldman School of Dental Medicine, Boston University
Dan Nathanson, Henry M. Goldman School of Dental Medicine, Boston University


Objectives: To explore a novel virtual inspection approach with a metrology software to provide a non-destructive in situ analysis in digital workflow.

Methods: A full coverage crown was fabricated over a typodont abutment (#8). A laboratory scanner (7 Series, Straumann) was used to scan the abutment. CAD software (CARES®, Straumann) was used to generate STL files for 3D-printering, milling and conventional waxing to fabricate wax patterns for lithium disilicate pressing.

Post processing, each crown was scanned to generate an STL file. A complete capture of the internal surface extending partially to the external was required per scan. A metrology software (Geomagic Control X, 3D Systems) was used to import both crown and abutment STL file for 2D and 3D virtual inspection.

Internal surface of the crown was normal inverted to make the inner surface to become an increased size abutment. This was initially fitted with the original abutment design. Final virtual inspection with points and heat mapping was done through best fitting both designs to simulate a crown seated a down all the way on the margin.

A specimen was selected for destructive analysis on the cement space via process of cementation, resin embedment, section, polishing, sputter coating and scanning electron microscopy. A regression analysis was done to compare 24 points for Buccal-Distal section and 23 points for Palatal-Distal section with 2D-cross-sectional view from the virtual analysis and SEM imaging.

Results: Multiple binding spots and gap on the inner surface of restoration can be viewed through a 3D color graph Fig.1. Regression analysis of 2D-virtual measurement to SEM measurement is shown in Fig.2.

Conclusions: The novel virtual inspection method showed a good fit with physical reality. This alignment finds its best fit through geometrical algorithm, rather than seating the crown through it’s path of insertion. This concept eliminates the seating error when a restoration comes in contact with any potential binding spots above the margin, which is frequently unaddressed.


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Student Presenter

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE