[Marginal fit of porcelain-fused-to-metal crowns: a comparative study of metal and porcelain butt margin].

Marginal openings and shoulder fit of porcelain butt margins and metal butt margins of porcelain fused-to-metal crowns have been investigated. Crown restorations were constructed directly onto the prepared teeth with 1 mm. square shoulder. Marginal openings and shoulder fit of labial surface and the cross-section of shoulder area then observed using optical microscope. Marginal fit was found better in porcelain fused-to-metal crowns with porcelain butt margin and also practically invisible neutrally-coloured join between crown and prepared tooth, was achieved with shoulder porcelain.