Related Experiment Video
Updated: Aug 28, 2025
Impact of Fabrication Techniques and Polishing Procedures on Surface Roughness of Denture Base Resins
Published on: January 17, 2025
Marginal and Internal Gap of Metal Copings Fabricated Using Three Types of Resin Patterns with Subtractive and
Hemavardhini Addugala1,2, Vidyashree Nandini Venugopal1, Surya Rengasamy1
1Department of Prosthodontics and Implantology, SRM Kattankulathur Dental College and Hospital, SRM Institute of Science and Technology, SRM Nagar, Chennai 603203, India.
This study compared the marginal and internal fit of Cobalt-Chromium copings made with milled polymethyl methacrylate (PMMA) versus 3D-printed acrylonitrile-butadiene-styrene (ABS) or polylactic acid (PLA) patterns. Milled PMMA patterns yielded superior marginal fit, while PLA patterns showed the best internal fit.
Area of Science:
- Dental Materials Science
- Prosthodontics
- Manufacturing Technologies
Background:
- Accurate fabrication of dental copings is crucial for prosthesis longevity.
- Limited data exists on the marginal and internal adaptation of copings produced via subtractive and additive manufacturing techniques.
Purpose of the Study:
- To evaluate and compare the marginal discrepancy and internal adaptation of Cobalt-Chromium (Co-Cr) copings fabricated using three distinct resin pattern fabrication methods: CAD milling and 3D printing (DLP technique).
Main Methods:
- Fifteen working casts were scanned, and computer-aided design (CAD) patterns were created.
- Resin patterns were fabricated using subtractive (CAD milled polymethyl methacrylate - PMMA) and additive (3D printed acrylonitrile-butadiene-styrene - ABS, and polylactic acid - PLA) technologies.
- Patterns were cast using the lost wax technique with Co-Cr alloy. Marginal and internal gaps were measured using the replica technique and optical microscopy.
Main Results:
- The CAD milled PMMA group exhibited the least marginal gap, followed by PLA and ABS printed groups (p=0.0001).
- No significant difference was found between PLA and ABS printed groups for marginal gap (p=0.899).
- The PLA printed group showed the least internal gap, followed by ABS and PMMA groups, though these differences were not statistically significant (p=0.638).
Conclusions:
- Full metal Co-Cr copings fabricated from milled PMMA patterns demonstrated a superior marginal fit compared to those from 3D printed patterns (PLA and ABS).
- Copings fabricated from PLA patterns exhibited the best internal fit, although statistical significance was not achieved across all groups.
- Both subtractive and additive manufacturing show potential for fabricating dental copings, with specific material and method choices influencing fit characteristics.
