Effect of ceramic material type on the fracture load of inlay-retained and full-coverage fixed dental prostheses

Abstract

Objective: Ceramic inlay-retained fixed partial denture (IRFPD) is a conservative prosthetic option but the mechanical durability of new high strength zirconia reinforced glass ceramic FPDs is not investigated. The purpose of this study was to compare fracture load of 3-unit ceramic FPDs. Materials and methods: Extracted premolars and molars (N ¼ 64) were used to create three test groups (IRFPDs) and one control group (full coverage FPD) (n ¼ 8). The teeth were embedded in PMMA resin with a mesiodistal distance of 6 mm. Premolars had a distal and molars had a mesial inlay preparation (width: 3 mm; height: 4 mm) in the test groups. IRFPDs were made from a zirconia reinforced lithium silicate (VS) or a monolithic zirconia. Zirconia IRFPDs received 2 types of surface treatments: sandblasting (Zr-IRFPD) or internal coating with feldspathic porcelain (ZrC-IRFPD). Control group was made from monolithic zirconia with the same connector size and zirconia surfaces were sandblasted (Zr-FPD). All restorations were cemented using a resin luting cement. After 5000 thermo-cycles, fracture load values (N) were determined with a universal testing machine at a crosshead speed of 0.75 mm/min. Data were analyzed using 1-way ANOVA and Tukeys post hoc test (p ˂ .05). Result: Fracture load (mean ± SD) of Zr-FPDs, Zr-IRFPDs and ZrC-IRFPDs were 672 ± 183, 672 ± 123 and 638 ± 59, respectively, being not statistically different (p > .05). VS-IRFPD exhibited statically lower values (391 ± 136). The predominant mode of failure was fracture at the connector area in all groups. Conclusion: The fracture load of 3-unit IRFPD was significantly affected by types of ceramics but the retainer design and surface treatment in Zr groups did not show a significant effect.

COMPARISON OF THE FRACTURE RESISTANCE BETWEEN INLAY RETAINED FIXED PARTIAL DENTURES FABRICATED FROM MILLED PEEK (BIOHPP) AND MONOLITHIC ZIRCONIA (In vitro study)

“…They related their results to the mechanical properties of zirconia, and the stiffness of the metal abutment used in their study, because of the different modulus of elasticity of Co-Cr alloy (180-240 GPa), compared to natural teeth (50-85 GPa for enamel, and 15-20 GPa for dentin). Contrary to our results, Kermanshah et al (2020) (20) and Mohsen et al (2010) (21) reported lower fracture resistance of monolithic zirconia IRFPDs. Kermanshah et al attributed this significant variation in results to the box shaped cavity preparation design since limited surface area was available for bonding, compared to occluso-proximal box preparation.…”

Assessment of Fracture Resistance of PEEK and Fibre Posts of the Endodontically Treated Teeth

“…It should be affirmed that the values of fracture load seen in this study were more than those corresponding to a normal adult forces of occlusion, which differ from 190-290 N (in the anterior teeth) to 200-360 N (in the posterior region) [23]. Finally, the results of this study might be directly related to the materials/ methodology utilized and might not reflect what could happen under different circumstances.…”

Effects of ceramic type, connector dimension, and thermomechanical-aging on the fracture resistance and fit of CAD-CAM produced inlay-retained fixed partial dentures

“…The masticatory forces differed from 500 to 900 N in the posterior region and it was reported that posterior fixed partial dentures should withstand at least 500 N 3,4,16) . The fracture load results in this study ranged between 384 (Suprinity) to 931 N (TZI) in nonaged groups.…”

“…The difference between two studies can be caused by differences in zirconia materials and designs of the restorations. Kermanshah et al 16) investigated the effect of ceramic material type on the fracture load of inlay-retained and full coverage fixed dental prostheses. Full coverage monolithic zirconia FPD, IRFPD made of monolithic zirconia, IRFPD made of monolithic zirconia internally coated by a porcelain layer, and IRFPD made of zirconia-reinforced lithium silicate were used to restore a maxillary second premolar.…”

“…CAD-CAM produced monolithic lithium disilicate and zirconia restorations improved the success of the IRFPDs. Zirconia-reinforced lithium silicate ceramics have shown superior mechanical properties than lithium disilicate ceramics 16) and they are indicated for anterior and posterior crowns, implant supported crowns or veneers. The mechanical properties of zirconiareinforced lithium silicate restorations are promising; however, to the best of our knowledge, studies that evaluated the fracture resistance of zirconia-reinforced lithium silicate IRFPDs were limited.…”