Endodontic Access Effect on Full Contour Zirconia and Lithium Disilicate Failure Resistance

Area of Science:

• Dental Materials Science
• Prosthodontics
• Restorative Dentistry

Background:

• Dental restorations require robust mechanical properties for longevity.
• Endodontic access can potentially compromise the structural integrity of full-contour crowns.
• Evaluating the impact of endodontic access on different ceramic materials and cementation techniques is crucial for clinical practice.

Purpose of the Study:

• To assess the influence of endodontic access preparations on the failure load resistance of monolithic yttria-stabilized zirconium dioxide (Y-TZP) and lithium disilicate (LD) crowns.
• To compare the outcomes between adhesively luted and conventionally luted crowns.

Main Methods:

• Seventy-two human maxillary molars were restored with either LD or Y-TZP crowns using CAD/CAM technology.
• Crowns were cemented adhesively or conventionally (glass ionomer cement - GIC).
• Endodontic access was performed on subgroups, followed by restoration of the access cavity and axial loading until failure.

Main Results:

• Adhesively luted LD and Y-TZP crowns showed no significant reduction in failure load after endodontic access.
• Y-TZP crowns cemented with GIC exhibited a significantly lower failure load following endodontic access.
• No significant difference was found in failure load between adhesively luted Y-TZP and LD crowns after endodontic access.

Conclusions:

• Endodontic access appears to have a minimal impact on the failure load resistance of adhesively bonded Y-TZP and LD crowns.
• Conventional glass ionomer cementation may compromise the structural integrity of Y-TZP crowns after endodontic access.
• Further research including fatigue testing and coronal seal evaluation is needed for definitive clinical recommendations.