International Journal of Chemical and Biochemical Sciences (ISSN 2226-9614)[/vc_column_text][/vc_column][/vc_row]

VOLUME 27(21) (2025)

Fracture Resistance of Lithium Disilicate and Advanced Lithium Disilicate Crowns Using Different Luting Cements: An In Vitro Study

Khaled Hassan*, Maged Mohammed Zohdy ^#, Ahmed Khaled Aboelfadl ^#

*BDS, Faculty of Dentistry, Ain Shams University, Egypt.

^#Fixed Prosthodontics Department, Faculty of Dentistry, Ain shams University, Egypt.

Abstract

                This in vitro study aimed to evaluate and compare the fracture resistance of lithium disilicate crowns fabricated from two CAD/CAM ceramic materials—IPS e.max CAD (Ivoclar Vivadent) and CEREC Tessera™ (Dentsply Sirona)—cemented using two different luting agents: glass ionomer cement and dual-cure self-adhesive resin cement. Thirty-two central incisor typodont teeth were prepared with a standardized 1.5 mm finish line and duplicated using cold-cure resin to produce uniform dies. Crowns were designed using Exocad software and milled via the CEREC MC XL system. Each crown was cemented using either Fuji I glass ionomer or Breeze resin cement, followed by thermal aging through 5000 thermocycles to simulate oral conditions. Fracture resistance was measured using a universal testing machine under compressive load. Statistical analysis included two-way ANOVA and independent t-tests, with significance set at p<0.05. No statistically significant differences were found between the two ceramic materials (p=0.441) or cement types (p=0.927). However, a significant interaction effect was observed between material and cement type (p=0.016, η²=0.19), indicating that the choice of cement significantly influenced fracture resistance depending on the ceramic material used. CEREC Tessera crowns cemented with resin exhibited the highest fracture resistance (1092.6±104.3 N), while IPS e.max CAD crowns cemented with resin showed the lowest (929.3±173.8 N). Within the limitations of this in vitro study, advanced lithium disilicate (Tessera) demonstrated superior performance when bonded with resin cement, while IPS e.max CAD showed consistent results across both cement types.

Keywords: Lithium disilicate, advanced lithium disilicate, fracture resistance, resin cement, glass ionomer cement, CAD/CAM, dental ceramics

Full length article    *Corresponding Author, e-mail: dr_khaledahmedhassan@hotmail.com, Doi # https://doi.org/10.62877/34-IJCBS-25-27-21-34