Influence of Cementation Protocol on Color Change and Fracture Resistance of Lithium Disilicate and Ultra-Translucent Zirconia Laminate Veneers (In-Vitro Study)

Document Type : Original Article

Authors

Lecturer of Fixed Prosthodontics, Faculty of Dentistry, Cairo University

Abstract

Objective: To evaluate color change and fracture resistance of ultra-translucent zirconia (KATANA UTML) versus lithium disilicate (IPS e.max CAD) laminate veneers when cemented using preheated resin composite versus adhesive resin cement.
Materials and Methods: Forty-four standardized laminate veneers (0.5mm labial, 1.5mm incisal thickness) were fabricated using CAD/CAM technology and divided into four groups (n=11): ZH (ultra-translucent zirconia + preheated resin composite), ZA (ultra-translucent zirconia + adhesive resin cement), LH (lithium disilicate + preheated resin composite), and LA (lithium disilicate + adhesive resin cement). Specimens were cemented to epoxy resin dies following standardised surface conditioning protocols. Color measurements were performed using spectrophotometry (CIE Lab* system), and fracture resistance was tested using universal testing machine at 135° loading angle until failure, and failure modes were inspected under stereomicroscope.
Results: All groups exceeded clinical acceptability threshold for color change (ΔE > 3.3), with ZH group exhibiting highest mean color change (16.30 ± 1.61) and ZA group demonstrating lowest (7.80 ± 1.77). Fracture resistance showed statistically significant differences between groups, with LH group achieving highest values (186.26 ± 27.43 N) and ZA group lowest (68.41 ± 8.44 N). Failure mode analysis revealed predominantly adhesive failures in ZA group (100%) versus mixed failures in preheated composite groups.
Conclusion: Material and cementation protocol influenced laminate veneer performance. All experimental groups exceeded clinically acceptable color change thresholds. Adhesive resin cement demonstrated superior color stability compared to preheated composite across both ceramic systems. For fracture resistance, lithium disilicate consistently outperformed ultra-translucent zirconia, with preheated composite providing mechanical enhancement

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Egyptian Dental Journal
Volume 71, Issue 4 - Serial Number 4
Fixed Prosthodontics, Removable Prosthodontics and Dental Materials
October 2025
Pages 3191-3206

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