Fracture strength of implant-supported hybrid abutment crowns in premolar region fabricated using different restorative CAD/CAM materials

Abstract

The present study investigated the fracture strength of hybrid abutment crowns (HACs) in the premolar region that were fabricated with different restorative computer-aided design/computer-aided manufacturing (CAD/CAM) materials. The abutment-implant structures were randomly assigned into four groups (n=11 per group): bi-layered zirconia restorations (BL), translucent zirconia (4Y-PSZ) restorations (TZ), lithium disilicate ceramic restorations (LD), and dispersed nanoparticle-filled composite resin restorations (CM). All restorations were adhesively bonded to the titanium abutments. After the restoration-abutment complex was tightened onto the implant, the fracture strength was measured. The TZ (2.06 kN) and LD (1.87 kN) groups had significantly higher median fracture strengths than the BL (1.12 kN) and CM (1.10 kN) groups. In terms of fracture resistance, the 4Y-PSZ and lithium disilicate ceramic monolithic restorations would be superior to bi-layered 3Y-TZP and composite resin monolithic restorations for HACs in the premolar region.

Influence of ceramic crown design (translucent monolithic zirconia vs. bilayered) of implant‐supported single crowns after mechanical cycling

“…This is consistent with our fractographic analysis ( Last, in terms of fracture resistance, our study revealed that monolithic translucent Zr crowns exhibited higher fracture resistance compared with other materials, consistent with the fatigue resistance data, and other studies in the scientific literature. [36][37][38] Fouda et al 2022 36 tested partially crystallized lithium disilicate and fully crystallized lithium disilicate, lithium metasilicate, 4Y-TZP, and 5Y-TZP monolithic zirconia under thermomechanical cycling; the highest mean fracture load was obtained for the 4Y-TZP and 5Y-TZP. 36,37 A recent study 38 that evaluated the fracture strength of implant-supported monolithic translucent zirconia with a similar composition to that used in our study reported the highest fracture strength values for implant-supported monolithic translucent zirconia compared with bilayered restorations, with values of 2.06 and 1.12 kN, respectively.…”

“…[36][37][38] Fouda et al 2022 36 tested partially crystallized lithium disilicate and fully crystallized lithium disilicate, lithium metasilicate, 4Y-TZP, and 5Y-TZP monolithic zirconia under thermomechanical cycling; the highest mean fracture load was obtained for the 4Y-TZP and 5Y-TZP. 36,37 A recent study 38 that evaluated the fracture strength of implant-supported monolithic translucent zirconia with a similar composition to that used in our study reported the highest fracture strength values for implant-supported monolithic translucent zirconia compared with bilayered restorations, with values of 2.06 and 1.12 kN, respectively. The differences in values between our study and theirs can be attributed to the fatigue test conducted before testing the fracture resistance because the fatigue test can cause the degradation of restorative materials properties and consequently propagate cracks that can weaken the material and reduce the maximum fracture resistance.…”

Bonding Strength of Various Luting Agents between Zirconium Dioxide Crowns and Titanium Bonding Bases after Long-Term Artificial Chewing

“…Initial clinical studies showed promising results for the hybrid abutment crown treatment option [15,16]. Takano and his team (2023) reported a fracture strength for the hybrid abutment crowns that exceeds the maximum masticatory force in the premolar region in a clinical situation [17]. However, long-term clinical experimental studies have not yet been conducted.…”