[Some observations of the interface of metal bonding porcelain by the electron probe surface shape analyzer].

Abstract

The metal bonding porcelain has been widely used for having the excellent qualities of color tone, corrosive resistance, abrasion proof and so on as the dental restorative material. And the many studies on its bonding mechanism have been done. However, there still remains some problems in operation of technical work. The Problems are how to choose polishing instruments for finishing cast metal before filled porcelain, and how to thin the part of dental neck as much as possible so that cast metal is not transmitted. So, as a clue to elucidate these problems, the appearance of metal/porcelain interface has been investigated by using the Electron Probe Surface Shape (EPSS) Analyzer. In this paper, two precious metals (KIK and HARD 2 on the market) and one nonprecious metal (TALLADIUM on the market) were used as base metal, and porcelain powder of two kinds, which were come onto the larket as VITA and DUCELAM, were used respectively. As polishing instruments, diamond point, carbide bur and pink point were used. The uneven images of metal/porcelain interface at parts of tooth top and neck, and middle part of those parts were observed respectively by EPSS analyzer, and the dimensional curves in section at three parts were also measured. The results obtained are as follows. VITA fused to two precious metals was observed to be fully bonded to the surfaces finished by any polishing instruments, and VITA was estimated to be able to get good bonding comparing with DUCERAM. But, in case of nonprecious metal, it was observed from the uneven images that metal/porcelain interfaces of both porcelains were clearly divided, and then this result might be evaluated as by way of the simply mechanical bonding predicted to be lower adhesive strength. The dimensional curves in section at metal/porcelain interface made by skilled and inexperienced dental technicians were distinctly characterized. That of skilled one suddenly varied when shifted from metal location to porcelain location. But, that of inexperienced one did not varied in any parts. Therefore, by measuring the dimensional curve in section using EPSS analyzer, the improvement of new technology in technical work is expected in future.