Deep caries and the resulting deep margins can be a restorative problem especially when the patient has a history of interproximal caries or a “high caries hostility index”. Generally speaking it’s better to have a crown that fits and fits on a meticulously placed deep restoration than a crown that doesn’t fit. And when the margin is very deep, then that is when a poorly prepared and poorly captured margin is most likely. An alternative is DME or deep margin elevation. Dentists have unintentionally placed margins on amalgam for decades with success. It’s likely that the outcomes will be even more favorable when done intentionally under controlled circumstances, under magnification and with no overhangs. Attached is a 7 year outcome with the crown placed on amalgam. Also attached are two very long term outcomes. When placing margins on restorative material, it is probably best to choose amalgam over composite as it does not rely on bonding which is poor under such conditions. It’s also advisable to evaluate the emergence profile of the tooth, it’s contact with adjacent teeth, and potential plunger cusps that led to the problem to begin with. Managing these variable can prevent food impaction and decrease the probability of failure to recurrent caries.