Marginal Fit and Internal Adaptation of Monolithic Zirconia 3-Unit Fixed Dental Prosthesis: In Vitro Study

Area of Science:

• Dental Materials Science
• Prosthodontics
• CAD/CAM Dentistry

Background:

• Monolithic zirconia (MZ) fixed dental prostheses (FDPs) offer enhanced aesthetics and strength.
• Evaluating CAD/CAM fabrication workflows is crucial for optimizing clinical outcomes.
• The full-chairside (FCH) workflow allows for same-day fabrication, potentially improving patient convenience.

Purpose of the Study:

• To compare the marginal and internal fit of 3-unit MZ FDPs.
• To evaluate two CAD/CAM fabrication workflows: full-chairside (FCH) and laboratory (LAB).
• To determine the clinical acceptability of FCH workflow for MZ FDPs.

Main Methods:

• Thirty 3-unit MZ FDPs were fabricated on a typodont model using FCH (n=15) and LAB (n=15) workflows.
• Digital impressions were obtained using CEREC Primescan.
• Marginal and internal fit were assessed using a dual-scan technique at occlusal, axial, and margin locations.

Main Results:

• Both FCH and LAB groups exhibited clinically acceptable marginal and internal fit.
• FCH FDPs showed fit measurements of 77.50 ± 29.99 μm (margin), 99.67 ± 21.58 μm (axial), and 150.03 ± 30.78 μm (occlusal).
• LAB FDPs showed fit measurements of 100.27 ± 27.06 μm (margin), 116.53 ± 17.90 μm (axial), and 142.30 ± 19.00 μm (occlusal).
• No statistically significant differences in fit were observed between the FCH and LAB groups.

Conclusions:

• The full-chairside (FCH) workflow yields monolithic zirconia 3-unit fixed dental prostheses with clinically acceptable marginal and internal fit.
• This study confirms the viability of the FCH workflow for fabricating multi-unit FDPs in a single patient visit.
• The FCH approach provides a predictable and efficient method for producing high-quality MZ FDPs.