Optimization of Lithium Disilicate Glass-Ceramic Crowns: Finish Line, Scanning, and Processing Methods

Area of Science:

• Dental materials science
• Biomaterials engineering
• Prosthodontics

Background:

• Lithium disilicate (LD) crowns are widely used in restorative dentistry.
• Optimizing fabrication factors is crucial for crown longevity and clinical success.
• Understanding the interplay between preparation design, scanning, and processing is essential.

Purpose of the Study:

• To determine the optimal combination of finish line type, scanning method, and ceramic processing technique for lithium disilicate crowns.
• To evaluate the impact of these factors on crown adaptation and fracture load.
• To identify the best method for achieving superior clinical performance in all-ceramic restorations.

Main Methods:

• Two abutment preparation designs (chamfer and rounded shoulder) were created.
• Extraoral and intraoral scanners were used to capture preparation data.
• Lithium disilicate crowns were fabricated using either CAD/CAM milling or a press technique with 3D printing.
• Crown adaptation (gap thickness) and fracture load were measured and analyzed.

Main Results:

• Scanning method and finish line type did not significantly affect gap thickness.
• The CAD/CAM milling process resulted in greater marginal gap discrepancies compared to the press technique.
• None of the investigated factors significantly influenced the fracture load of the crowns.
• The press technique with a chamfer preparation and extraoral scanning (PRE-CE) demonstrated optimal adaptation and met the target fracture load.

Conclusions:

• The press technique, when combined with a chamfer abutment preparation and extraoral scanning, represents the optimal approach for fabricating lithium disilicate crowns.
• This combination yields superior adaptation and adequate fracture resistance for all-ceramic restorations.
• Clinical recommendations favor the press technique for enhanced performance in dental prosthetics.