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Effect of Split-File Digital Workflow on Crown Margin Adaptation
Ryan R Sheridan1,2, Ronald Verrett2, Stephan Haney2
1Prosthodontics Residency, Air Force Postgraduate Dental School, Uniformed Services University of the Health Sciences, Lackland AFB, TX.
Summary
The complete digital split-file protocol for dental restorations resulted in larger marginal gaps compared to segmental digital and analog techniques. Adjustments were needed for 52 restorations to achieve proper contours.
Area of Science:
- Dental materials science
- Digital dentistry
- Prosthodontics
Background:
- Computer-aided design/computer-aided manufacturing (CAD/CAM) integration in dentistry is advancing rapidly.
- Scientific validation of new CAD/CAM protocols, such as the complete digital split-file approach, is crucial for clinical adoption.
Purpose of the Study:
- To evaluate a complete digital split-file protocol against segmental digital and analog techniques for restoring maxillary anterior edentulous spaces.
- To compare the marginal gap accuracy of custom abutments and crowns fabricated using different digital and analog workflows.
Main Methods:
- Four workflows were assessed: complete digital (CD), segmental digital (SD), milled wax (AM), and heat pressed/hand waxed (AH).
- The CD workflow involved separate abutment and crown files for zirconia abutments and zirconia/lithium disilicate crowns.
- Restorations were evaluated for marginal gap using scanning electron microscopy (SEM) before and after adjustments, with adjustments recorded.
Main Results:
- The complete digital (CD) workflow showed a statistically significant larger mean marginal gap (69 μm) compared to SD (26 μm), AM (32 μm), and AH (26 μm) groups after adjustment.
- The segmental digital (SD), milled wax (AM), and heat pressed/hand waxed (AH) workflows demonstrated statistically similar marginal gap results.
- 52 out of 60 digitally produced restorations in the CD group required adjustments for horizontal marginal offset to achieve proper contours.
Conclusions:
- While the complete digital split-file protocol yields marginal gap sizes within clinical standards after adjustment, it necessitates significant contour adjustments.
- Segmental digital and analog techniques provided comparable and smaller marginal gap results than the complete digital split-file protocol in this study.
- Further refinement of the complete digital split-file protocol may be needed to minimize contour discrepancies and adjustment requirements.
