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An In Vitro Comparison of the Marginal Adaptation Accuracy of CAD/CAM Restorations Using Different Impression Systems
Marwa Shembesh1, Ala Ali1, Matthew Finkelman1
1Department of Prosthodontics and Operative Dentistry, Tufts University School of Dental Medicine, Boston, MA.
Summary
This study compared marginal adaptation of zirconia fixed dental prostheses (FDPs) using different digital scanning methods. All tested digital impression techniques yielded clinically acceptable marginal gaps for FDPs.
Area of Science:
- Dental materials science
- Digital dentistry
- Prosthodontics
Background:
- Accurate marginal adaptation of fixed dental prostheses (FDPs) is crucial for long-term clinical success.
- Digital impression techniques offer potential advantages over conventional methods in terms of accuracy and efficiency.
Purpose of the Study:
- To compare the marginal adaptation of 3-unit zirconia FDPs fabricated using intraoral digital scanners (Lava True Definition, Cadent iTero), conventional silicone impressions, and master casts scanned with an extraoral scanner (3Shape lab scanner).
Main Methods:
- A reference model with prepared teeth for a 3-unit FDP was used.
- Impressions were made using PVS material, and casts were scanned.
- Intraoral scans were obtained using Cadent iTero and Lava True Definition scanners.
- Zirconia FDPs were milled, and marginal adaptation was evaluated using an optical comparator.
Main Results:
- Mean marginal gaps ranged from 26.6 μm (Lava True Definition) to 81.4 μm (PVS impression scan).
- Statistically significant differences were found among all tested groups (p < 0.001).
- All groups demonstrated marginal discrepancy values within the clinically acceptable limit of 120 μm.
Conclusions:
- All tested impression techniques resulted in marginal gaps within the clinically acceptable range.
- The Lava True Definition intraoral scanner produced the lowest mean marginal gap, followed by the extraoral scan of the master cast, Cadent iTero, and PVS impression scan.
