Reliability and mode of failure of bondedmonolithic monolithic and multilayer ceramics

Objective. To evaluate the reliability of monolithic and multilayer ceramic structures used in the CAD-on technique (Ivoclar), and the mode of failure produced in ceramic structures bonded to a dentin analog material (NEMA-G10). Methods. Ceramic specimens were fabricated as follows (n=30): CAD-on-trilayer structure (IPS e.max ZirCAD/IPS e. max Crystall./Connect/IPS e. max CAD); YLD-bilayer structure (IPSe. max ZirCAD/IPS e. max Ceram); LDC-monolithic structure (IPS e. max CAD); and YZW monolithic structure (Zenostar Zr Translucent). All ceramic specimens were bonded to G10 and subjected to compressive load in 37 degrees C distilled water until the sound of the first crack, monitored acoustically. Failure load (L-f) values were recorded (N) and statistically analyzedusing Weibull distribution, Kruskal-Wallis test, and Student-Newman-Keuls test (alpha=0.05). Results. L-f values of CAD-on and YZW structures were statistically similar (p=0.917), but higher than YLD and LDC (p < 0.01). Weibull modulus (m) values were statistically similar for all experimental groups. Monolithic structures (LDC and YZW) failed from radial cracks. Failures in the CAD-on and YLD groups showed, predominantly, both radial and cone cracks. Significance. Monolithic zirconia (YZW) and CAD-on structures showed similar failure resistance and reliability, but a different fracture behavior. (C) 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.