Metal-to porcelain bond strength test with an additional acoustic and optical sensor system

Introduction: The aim of this study was to investigate the bond strength between a CoCr alloy and 18 different veneering porcelains using additional acoustic and optical sensors. Material and Methods: The veneering porcelains (1=Vintage Halo, 2=IPS Classic V, 3=Creation CC, 4=GC Initial MC, 5=Imagine Reflex, 6=VMK 95, 7=Antagon Interaction, 8=Omega 900, 9=Carat, 10=Starlight Ceram, 11=EX-3, 12=HeraCeram, 13=VM 13, 14=Duceram Kiss, 15=Vintage, 16=IPS d.Sign, 17=Nuance 850, 18=IPS InLine) fused to Ankatit U (62.3Co-25.2Cr-6Mo-5W) were tested with 10 specimens each according to ISO 9683. In the 3-point-bending device a microphone capsule was incorporated to capture synchronously an acoustic signal of crack initiation in addition to the force signal. Furthermore, a video was recorded at a magnification of 200 times during the bending test in order to identify the start of debonding of the veneering ceramics. Results: All of the investigated veneering porcelains exceeded the bond strength limit of 25 MPa required by the standard. The values ranged from 29.4 ± 2.5 (#18) until 39.6 ± 2.3 MPa (#1). The acoustic signals indicated an earlier failure of bond strength (crack initiation) before reaching the maximum force. Based on the acoustic signals the values reached from 11.52 ± 12.85 (#10) to 38.76 ± 3.66 MPa (#1). With the optical sensor system it was not possible to accurately detect the start of crack initiation since the available magnification of 200 was too low. Conclusion: Additional recording of the acoustic signal supports the detection of the real crack initiation. Supported by ANKATIT-ANKA Guss GmbH. Keywords: Bond strength metal to porcelain