Comparison of the bond strength of porcelain to titanium substructure made by EBM or Milling method

One of the main reasons for the failure of metal-ceramic restorations is insufficient bond strength between porcelain and metal, which depends on various factors, including the manufacturing method. The purpose of this study was to evaluate the effect of manufacturing method on bond strength of porcelain to titanium substructure made by EBM or Milling method.

In this in-vitro study two groups comprised of twenty metal bars each were prepared with EBM or Milling method. first a resin bar was molded into standard ISO:9693 dimensions of 25 mm × 3 mm × 0.5 mm. then it scanned and Ten bars from each group were manufactured using milling device from titanium disks or from an EBM device from Ti-6Al-4Va titanium alloy. bars were sandblasted with 110 μm aluminum oxide particles and were impregnated with bonding agent before the application of 1/1 mm of porcelain onto 8 mm × 3 mm rectangular area in the center of each bar porcelain. Afterwards, bond strengths of the samples were assessed using 3-point bending test with a Universal Testing Machine. Statistical analysis was performed using T-test and a significant level of 0.05 was considered

The mean bond strength of EBM group (34.36±3.67MPa) was lower than Milling group (46.52±4.34 MPa) and there was statistically significant difference between groups (p-value<0.001).

Bond strength of EBM-manufactured samples were lower than milled group while both groups exceed the minimum requirement of bond strength for metal-ceramic restoration according to ISO9693.