Fit of all-ceramic posterior fixed partial denture frameworks in vitro

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Prosthodontics

Background:

• Accurate fit of all-ceramic fixed partial denture (FPD) frames is crucial for long-term clinical success.
• Traditional fabrication methods like slip casting have limitations in achieving precise marginal and internal adaptation.
• Advancements in digital dentistry, including computer-assisted design/computer-aided machining (CAD/CAM), offer potential for improved FPD fabrication.

Purpose of the Study:

• To evaluate and compare the marginal and internal fit of three-unit all-ceramic FPD frames.
• To assess frames fabricated using CAD/CAM and CAM techniques with various ceramic materials.
• To compare digital fabrication methods against traditional slip-casting for ceramic FPDs.

Main Methods:

• Scanning electron microscopy (SEM) was employed to assess marginal and internal fit.
• All-ceramic FPD frames were fabricated using CAD/CAM and CAM techniques with infiltration ceramic, yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) zirconia, and glass ceramic blocks.
• Slip-cast infiltration ceramic served as a control group.

Main Results:

• CAD/CAM fabricated frames demonstrated significantly smaller cementation interface widths compared to slip-cast controls.
• Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) zirconia frames fabricated by CAD/CAM and CAM showed superior marginal and internal fit over other materials and methods.
• Specifically, Cerec Y-TZP zirconia and DCS Y-TZP zirconia exhibited better fit than Cercon Y-TZP zirconia.

Conclusions:

• CAD/CAM technology provides superior marginal and internal accuracy for all-ceramic FPD frames compared to slip casting and CAM techniques.
• The choice of ceramic material and fabrication method significantly impacts the fit of dental restorations.
• Digital fabrication workflows enhance the precision of ceramic FPDs, potentially improving clinical outcomes.