A Polymer-Infiltrated Ceramic as Base Adherent in an Experimental Specimen Model to Test the Shear Bond Strength of CAD-CAM Monolithic Ceramics Used in Resin-Bonded Dental Bridges

Abstract

Traditional load-to-failure tests fail to recreate clinical failures of all-ceramic restorations. Experimental fabrication, similar to prosthetic laboratory and clinical procedures, best predicts future clinical performance. A hybrid ceramic adherend, mechanically similar to a human tooth, was tested by comparing the shear bond strength (SBS) and fracture mode of four restorative materials adhered with a dual-cure adhesive cement. Surface energy, shear bond strength (SBS), and fracture mode were assessed. Vita Enamic (ENA), Vita Suprinity (SUP), Vita Y-TPZ (Y-ZT), and a nanohybrid composite (RES) (control group) cylinders, adhered with RelyX Ultimate to ENA blocks were assembled in experimental specimens simulating a 3-unit resin-bonded dental bridge. The ENA adherend was ground or treated with 5% hydrofluoric acid for 60 s. Monobond Plus was used as the coupling agent. Mean shear stress (MPa) was calculated for each group. Forest plots by material elaborated after calculating the difference in means and effect size (α = 0.05; 95% CI; Z-value = 1.96) revealed significant differences in the shear force behavior between materials (p < 0.01). RES (69.10 ± 24.58 MPa) > ENA (18.38 ± 8.51 MPa) > SUP (11.44 ± 4.04 MPa) > Y-ZT (18.48 ± 12.12 MPa). Y-ZT and SUP exhibited pre-test failures. SBS was not related to surface energy. The failure mode in the Y-ZT group was material-dependent and exclusively adhesive. ENA is a potential adherend for dental materials SBS tests. In this experimental design, it withstood 103 MPa of adhesive stress before cohesive failure.

Shear Bond Strength of Simulated Single-Retainer Resin-Bonded Bridges Made of Four CAD/CAM Materials for Maxillary Lateral Incisor Agenesis Rehabilitation

“…Adhesion between CAD/CAM materials and teeth substrates depends on adhesive systems 34 and chemical interactions that occur between functional monomers and tooth components, 35 which in turn depend on the properties of the materials, which are crucial to the success of adhesive restorations. 22 In this experimental setting, RelyX Ultimate cement was used based on recent research 21 23 by its adhesive efficiency and versatility when paired with Y-ZPT, ENA, and SUP ceramics. Also, adhesive protocols followed literature guidelines.…”

“…Polycrystalline zirconia (Y-ZPT) was used as control material. Based on previous research, 21 a photoinitiated dual-cured adhesive cement, RelyX Ultimate (RU; 3M ESPE, Seefeld, Germany), used in a three-step adhesive strategy, was used to adhere the experimental RBBs to an artificial tooth.…”

“… 17 Despite the low stiffness, 18 it is quite stable under extreme acid exposure, and cyclic loading does not affect its properties. 19 Its unique polymer-based microstructure is essential for the micromechanical bond and the performance of the adhesive interface 20 21 due to a decreased crack propagation. 22 High translucency, fluorescence, and opalescence are the main characteristics of Vita Suprinity (SUP; VITA Zahnfabrik), according to the manufacturer.…”