A 3-year clinical evaluation of a porcelain inlay system

The porcelain inlay technique was described over a century ago, and, although not yet used as a routine restorative procedure, may prove to provide restorations of unsurpassed functional and aesthetic qualities in certain situations. The aim of this study was to investigate the handling properties and clinical characteristics of a porcelain inlay system, to highlight any advantages and disadvantages of the restorations under investigation, and to indicate further studies as considered appropriate.

Fifty moderate to large-sized Class 1 and Class II restorations of a porcelain inlay system were investigated in premolar and permanent molar teeth of 27 adult patients over a 3-year period using modified United States Public Health codes and criteria. Selected restorations were evaluated indirectly by scanning electron microscopic analysis.

There was a high early rate of bulk fracture. By 6 months post-placement there had been a limited deterioration in marginal integrity associated with 20% of the remaining restorations, but this trend was not seen to continue. Patient acceptance was very favourable.

It was concluded that the system under investigation afforded a technique-sensitive method of producing tooth-coloured restorations. Proposals for further work include investigations of the fitting accuracy of indirect tooth-coloured restorations, cavity design modifications and the use of alternative bases and luting agents.