Effect of electrospark deposited surface layers on bond strength of titanium–porcelain

Abstract

Casting of titanium can be successfully used in prosthodontic applications, but it demands special machines and protection gas to avoid oxidation of the metal. The aims of this study are to investigate the bond compatibility between porcelain and titanium using three-point bending, oxide adherence and thermal expansion tests, and to compare the results with those of a conventional titanium–porcelain system. Titanium alloy surfaces were modified with Nb, YG8 and silicon electrode by electrospark surface modification process. The effect of electrospark surface depositing (ESD) layers on bond strength of titanium to porcelain was evaluated comparatively. Some reasons about bond strength of titanium to porcelain were discussed. Results indicate that ESD modified layer prepared in atmosphere using Si electrode can obtain the strongest bonding to porcelain. The ESD modified layer show metallurgical bond to Ti substrate. In addition, the facts that rough surface can help to improve physic bond, similar nature can also help to chemical link and compact ESD layer represent good high temperature oxidation resistance are the reasons that enhance good bond strength of titanium to porcelain.