IADR Abstract Archives
Mechanical Properties of Hybrid Resin Blocks Immersed in a Water for one-Year
Objectives: The aim of this study was to evaluate physical properties of hybrid resin blocks for long-term aging. The clinical application of hybrid resin crowns manufactured by CAD/CAM has been expanding in Japanese dental field after approval for a molar crown in the national health insurance. Therefore, the hybrid resin crowns have been proposed as an inexpensive and cosmetic restoration alternative to all ceramics or metal crowns. On the other hand, these restorations are required long-term durability as permanent molar crown to provide excellent prognosis and patient satisfaction. In this study, we evaluated 3-point flexural strength and surface morphology of five hybrid resin blocks after immersion in a water for one-year.
Methods: Mechanical properties were measured by 3-point flexural strength test. Specimens were prepared in accordance with ISO 6872 and produced by five manufactures: CERASMART 300; CS (GC), KZR-CAD HR3; KZ (YAMAKIN), Estelite P Block; EP (Tokuyama Dental), AVENCIA P BLOCK; AP (Kuraray), HS SUPER HARD; HS (SHOFU). The specimens were divided into two groups, dry and aging. Dry group was immediately tested after specimen prepared. Aging group was immersed into a distilled water at 37 °C for one-year. Each specimen was placed on universal testing machine (AUTOGRAPH AG-1kNIS, SHIMADZU) and applied the load at a cross head speed of 1 mm/min until it fractures. All data were statistically analyzed using one-way ANOVA and Tukey-Kramer multiple-comparison test.
Results: The degradation of water immersion for long-term was shown in flexural strength of all manufactures (p<0.01). However, CS, EP and AP showed significantly high physical durability in aging group (p<0.05). Moreover, CS showed the highest breaking energy compared to all manufactures in both dry and aging group (p<0.05). The high breaking energy of CS indicated that is not easily broken even under occlusal force.
Conclusions: The hybrid resin block which has high physical durability and impact dispersion provides clinical advantages for permanent restorations.
Methods: Mechanical properties were measured by 3-point flexural strength test. Specimens were prepared in accordance with ISO 6872 and produced by five manufactures: CERASMART 300; CS (GC), KZR-CAD HR3; KZ (YAMAKIN), Estelite P Block; EP (Tokuyama Dental), AVENCIA P BLOCK; AP (Kuraray), HS SUPER HARD; HS (SHOFU). The specimens were divided into two groups, dry and aging. Dry group was immediately tested after specimen prepared. Aging group was immersed into a distilled water at 37 °C for one-year. Each specimen was placed on universal testing machine (AUTOGRAPH AG-1kNIS, SHIMADZU) and applied the load at a cross head speed of 1 mm/min until it fractures. All data were statistically analyzed using one-way ANOVA and Tukey-Kramer multiple-comparison test.
Results: The degradation of water immersion for long-term was shown in flexural strength of all manufactures (p<0.01). However, CS, EP and AP showed significantly high physical durability in aging group (p<0.05). Moreover, CS showed the highest breaking energy compared to all manufactures in both dry and aging group (p<0.05). The high breaking energy of CS indicated that is not easily broken even under occlusal force.
Conclusions: The hybrid resin block which has high physical durability and impact dispersion provides clinical advantages for permanent restorations.