Bending Fracture of Different Zirconia-Based Bioceramics for Dental Applications: A Comparative Study

Abstract

The fabrication of fixed dental prostheses using aesthetic materials has become routine in today’s dentistry. In the present study, three-unit full zirconia fixed prosthetic restorations obtained by computer-aided design/computer-aided manufacturing (CAD/CAM) technology were tested by bending trials. The prostheses were intended to replace the first mandibular left molar and were manufactured from four different types of zirconia bioceramics (KatanaTM Zirconia HTML and KatanaTM Zirconia STML/Kuraray Noritake Dental Inc.; NOVAZir® Fusion float® ml/NOVADENT/Dentaltechnik; and 3D PRO Zirconia/Bloomden Bioceramics). In total, sixteen samples were manufactured—four samples per zirconia material. Additionally, the morphology, grain size area distribution, and elemental composition were analyzed in parallelepiped samples made from the selected types of zirconia in three different areas, noted as the upper, middle, and lower areas. The scanning electron microscope (SEM) analysis highlighted that the grain size area varies with respect to the researched area and the type of material. Defects such as microcracks and pores were also noted to a smaller extent. In terms of grain size area, it was observed that most of the particles in all samples were under 0.5 μm2, while the chemical composition of the investigated materials did not vary significantly. The results obtained after performing the bending tests showed that a zirconia material with fewer structural defects and an increased percentage of grain size area under 0.5 µm2, ranging from ~44% in the upper area to ~74% in the lower area, exhibited enhanced mechanical behavior. Overall, the resulting values of all investigated parameters confirm that the tested materials are suitable for clinical use.

Materials and manufacturing techniques trends in prosthetic dentistry.

“…To study the bending fracture of three-unit full zirconia fixed prosthetic restorations obtained by CAD-CAM technology, P. Fischer et al [11] performed bending tests on different types of zirconia bioceramic (KatanaTM Zirconia HTML and KatanaTM Zirconia STML/Kuraray Noritake Dental Inc.; NOVAZir® Fusion float® ml/NOVADENT/Dentaltechnik; and 3D PRO Zirconia/Bloomden Bioceramics). The three-unit full zirconia fixed prosthetics obtained were codified by K-H, N, B, and K-S respectively.…”

“…After the mechanical tests were performed, P. Fischer et al [11] emphasized that the bending strength of all three-unit dental prostheses tested is in correlation with the size, shape, and distribution of particles along with the presence of material defects. Nevertheless, the bending tests indicated that the highest forces at the failure values were registered for the B zirconia samples, followed by K-H and N samples, while the lowest values were obtained for the K-S specimens.…”

Fracture Resistance of CAD/CAM Implant-Supported 3Y-TZP-Zirconia Cantilevers: An In Vitro Study

“…Aesthetics plays a very important role in our society; as such, oral rehabilitation must take into account aesthetic requirements by using materials that meet the expectations of patients [ 11 , 12 ]. However, this should not compromise the strength, clinical success, and longevity of dental prostheses.…”

“…Due to their aesthetic properties, there has been a substantial increase in the use of zirconia and ceramics in prosthetic rehabilitation [ 9 , 11 , 12 ]. This increase is due not only to the aesthetic component, but also due to these materials’ high fracture resistance and other mechanical properties [ 11 ], their excellent biocompatibility, and their physical properties [ 9 , 11 , 15 ].…”

“…Currently, yttrium-stabilized tetragonal zirconia (Y-TZP) is the ceramic material that has the highest fracture resistance [ 16 ], and it is the ceramic material most used as a rehabilitation material in high stress areas due to its high strength [ 15 ]. It should be noted that today, the elaboration of zirconia structures is more optimized, accurate, and reliable, due to the development of computerized CAD–CAM systems [ 12 , 17 , 18 , 19 , 20 ]. They may be a viable alternative for full-arch implant-supported rehabilitations, being able to achieve high 5-year survival rates with minimal prosthetic complication rates since they were not subject to chipping and wear, even if work needs to be performed to improve their esthetics [ 21 , 22 ].…”