Improvement in dental porcelain bonding to milled, noncast titanium surfaces by gold sputter coating

Purpose: This study evaluated the adherence of dental porcelain to a milled, noncast titanium (Ti) surface with a gold sputter coating to evaluate a possible new practical surface treatment for enhancing the bond strength between Ti and porcelain. Materials and Methods: Milled, noncast Ti strips were created by computer-aided design and manufacturing processes. The milled, noncast Ti strips were sandblasted with alumina particles and were then sequentially subjected to gold sputter coating treatments of 150- and 300-second duration. Low-fusion dental porcelain was then sintered onto the surface-treated Ti strips. The bond strengths of the Ti/porcelain specimens were evaluated using a three-point bending test (ISO 9693). Surface characterizations of the specimens were carried out with X-ray photoelectron spectrometry, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Results: The results indicated that the bond strengths of all the Ti/porcelain groups were greater than the minimum requirement (25 MPa) as prescribed by ISO 9693. The gold sputter coating increased the oxidation resistance (or decreased the oxide content) of the Ti surface during porcelain sintering, which positively affected the bond strength of Ti/porcelain (approximately 36 MPa) compared to the untreated Ti/porcelain specimen (approximately 29 MPa). The fracture morphologies of all the Ti/porcelain groups revealed an adhesive bond failure as the interfacial fracture mode between the Ti and the porcelain. Conclusions: A practical and simple sandblasting/gold sputter coating treatment of Ti surfaces prior to porcelain sintering significantly strengthens the bond between the milled, noncast Ti and the dental porcelain.