1Rafal Kareem Rasheed, B.Sc. and 2Nidhal Sahib Mansoor, PhD
1, 2Department of Prosthetic Dental Technology, College of Health and Medical Techniques, Middle Technical University, Baghdad, Iraq.
Corresponding Author: Rafal kareem Rasheed
Received 02 September, 2022.
Accepted for publication on September 30, 2022.
Published December 01, 2022.
Background Back in the 1980s, CAD/CAM device (computer-aided design, computer-aided manufacturing) technology was introduced to the world of dentistry. This system was designed to acquire data using photographs and a high-resolution scanner and to mill restorations using a 5-axis machine. Objectives This study aims to compare the shear bond strength of dental alloy cobalt chromium metal substrate created using multiple methods fused by dental ceramics with and without the addition of a bonding agent. Materials and Methods Forty disc specimens were used using CAD/CAM technology to create the Co-Cr alloy specimens, subtractive technique and sub-additive technique (n=20 each). Soft metal milling was used to design the discs (kera®soft–Disc) and a 3D printer machine selective laser melting (Mediloy® S-Co) using software computer-aided design program (Exocad Dental CAD, Darmstadt, Germany, v.2016). Dental ceramic (VITA VMK Master ®) was applied to the specimens. Each group was subdivided according to direct exposure of discs to bonding ageing material (Vita NP Bond paste), into two sub-groups (n=10 discs). A test for shear bond strength (SBS) was used to assess the bond strength. Before the SBS test, the average surface roughness (Ra) of each group was evaluated. This takes place after abrading with 110µm aluminium oxide particles, and then the metal and ceramic interfaces were inspected using test scanning electron microscopy (SEM) at a magnification of 500X. Test dispersive X-ray spectroscopy was used to determine the elements that make up the material bonding agents (EDS). Results were compared before and after the addition of the bonding agent. Under a digital microscope, SBS diagnostic tests and failure mechanisms were captured. The Least Significant Difference (LSD) statistical analysis of the data was performed at (P=0.05). Results No statistically significant variation of the test roughness between milling and laser was noticed, therefore differing techniques seem to affect the SBS test for metal-ceramic restoration. A bonding material applied to the CAD/CAM technique group was the greatest among the 3D printer metal laser groups, cobalt chromium dental alloy specimens with applied bonding agents exhibited significantly stronger bond strength than Co-Cr groups without applied agent material. Conclusion It can be concluded from this study that the metal fused to ceramic restoration bond strength varies depending on the production techniques and the bonding agent used.