For those dentists out there who are curious about what is acceptable when fitting your indirect restorations such as crowns, bridges, implant crowns and bridges, inlays and onlays, here are some useful facts on marginal fitting:
Quality ratings for marginal fitting:
1. Clinically excellent: no gap; smooth transition between margin and tooth; probe does not catch
2. Clinically acceptable: space of 150 µm; slight probe catching
3. Clinically unsatisfactory: space > 150 µm - 250 µm; probe penetrates into the gap, but no dentine exposed.
4. Clinically poor: space > 250 µm; probe penetrates into the gap and dentine exposed.
It is possible to use probes with a tip size of 250um and therefore check the fitting with accuracy prior to cementation.
