If there is a 0.3mm discrepancy at the margin when seating a crown, what should be done?

When there is a 0.3mm discrepancy at the margin when seating a crown, the appropriate course of action is to remake a new crown. This decision is crucial because a discrepancy of this size can lead to several complications, including issues with plaque retention, periodontal health, and the overall fit of the crown.

A proper crown margin should ideally be flush with the tooth preparation, and any noticeable gap can compromise the seal and lead to leakage or decay. Remaking the crown ensures that the fit is accurate and that the alignment of the crown to the existing tooth structure is optimal. This prevents potential future issues related to dental health and provides a better long-term outcome for the patient.

While reducing the inner surface of the crown or smoothing the enamel at the margin might seem like temporary fixes, they do not address the underlying issue of fit and could potentially worsen the situation. Hand burnishing crown margins is also not a reliable solution for a discrepancy of this scale, as it does not correct the dimensional inaccuracies present in the crown itself. Thus, remaking the crown is the most viable option to ensure proper fit, function, and aesthetic outcome.