IADR Abstract Archives
Wear properties of lithium silicate glass ceramic block for CAD/CAM
Objectives: Lithium silicate glass ceramics are known as clinically useful dental materials from the viewpoint of aesthetics and biological compatibility. In particular, lithium silicate glass ceramic blocks for CAD/CAM technology are used for chair-side and potential one-day treatment. As dental materials are used for long term in the oral cavity, it is important that the wear properties are closely related to aesthetics of the restorations. The purpose of this study was to evaluate the wear properties of newly developed lithium silicate glass ceramic block for CAD/CAM.
Methods: The wear properties of “Initial LiSi Block” (LS, GC Corp.), “IPS e.max CAD” (EM, Ivoclar Vivadent) and “Celtra Duo” (CD, Dentsply Sirona) were evaluated by two-body wear test. Polished specimens (φ2.1mm) were prepared with Cera Shine (GC Corp.). These specimens were attached to the testing machine and contacted with sintered and polished with #4000 SiC paper Hydroxyapatite (HAp) as antagonist in water. The testing machine performed load with sliding movement to the contact surface of the specimens for 10,000 cycles. The depth of wear was calculated from the difference between baseline and worn specimen height, and one-way ANOVA was used to assess the significant difference. To analyze crystal structure of each material, SEM observation was carried out.
Results: In wear test, LS showed lower depth of wear than EM (p<0.05) and CD (p<0.01). Regarding damage to antagonists, LS group also showed lower depth of wear than EM and CD. SEM observation confirmed high density and fine crystal precipitation in LS glass matrix and revealed that lithium disilicate crystals of LS were smaller than that of EM and CD.
Conclusions: Due to unique crystal structure, Initial LiSi Block as a new lithium silicate glass ceramic block has not only superior wear resistance but also less damage against antagonists. These results suggest that Initial LiSi Block is a useful restorative dental material long term.
Methods: The wear properties of “Initial LiSi Block” (LS, GC Corp.), “IPS e.max CAD” (EM, Ivoclar Vivadent) and “Celtra Duo” (CD, Dentsply Sirona) were evaluated by two-body wear test. Polished specimens (φ2.1mm) were prepared with Cera Shine (GC Corp.). These specimens were attached to the testing machine and contacted with sintered and polished with #4000 SiC paper Hydroxyapatite (HAp) as antagonist in water. The testing machine performed load with sliding movement to the contact surface of the specimens for 10,000 cycles. The depth of wear was calculated from the difference between baseline and worn specimen height, and one-way ANOVA was used to assess the significant difference. To analyze crystal structure of each material, SEM observation was carried out.
Results: In wear test, LS showed lower depth of wear than EM (p<0.05) and CD (p<0.01). Regarding damage to antagonists, LS group also showed lower depth of wear than EM and CD. SEM observation confirmed high density and fine crystal precipitation in LS glass matrix and revealed that lithium disilicate crystals of LS were smaller than that of EM and CD.
Conclusions: Due to unique crystal structure, Initial LiSi Block as a new lithium silicate glass ceramic block has not only superior wear resistance but also less damage against antagonists. These results suggest that Initial LiSi Block is a useful restorative dental material long term.