Evaluation of low-fusing porcelain bonded to dental cast Ti–Cr alloys

Abstract

The purpose of this study was to compare the bonding characteristics of titanium porcelain Duceratin bonded to Ti–Cr alloys and commercially pure titanium (c.p. Ti). In addition, the thermal expansion coefficient (CTE) of all Ti–Cr alloys and c.p. Ti was also evaluated. The experimental metals used for this study include c.p. Ti, Ti–5Cr, Ti–10Cr, Ti–20Cr, Ti–25Cr and Ti–30Cr alloys (in wt.%). This study evaluated the bond strengths between commercial titanium porcelain Duceratin and Ti–Cr alloys. All the Ti–Cr alloys were tested for the determination of CTE with a dilatometer operating from room temperature up to 650 °C at a heating rate of 5 °C/min. The bond strengths of all the Ti–Cr alloys were higher than that of c.p. Ti. With the exception of Ti–5Cr and Ti–10Cr alloys, the bond strengths of all the other Ti–Cr alloys exceeded the lower limit value in the DIN 13.927 standard for the three-point bending test (25 MPa). By contrast, c.p. Ti surface after debonding exhibited the least amount of retained porcelain on the metal surface, and a higher rate of adhesive bond failure. More traces of retained porcelain were observed on specimens that contained higher alloying elements, such as Ti–25Cr and Ti–30Cr alloys, attesting to a better mechanical performance. In addition, the CTE of the Ti–Cr alloys ranged from 10.0 × 10 −6/°C (Ti–10Cr) to 11.8 × 10 −6/°C (Ti–30Cr), and were higher than that for c.p. Ti (10.1 × 10 −6/°C).