Sometimes, a tooth is treatment planned to be restored with filling, but the decay or fracture is so extensive that a direct restoration, such as amalgam or composite, would compromise the structural integrity of the restored tooth by possibly undermining the remaining tooth structure or providing inferior strength to occlusal (i.e. biting) forces. In these situations, a milled porcelain restoration may be indicated. When porcelain is used, the tooth-to-restoration margin may be so fine at the line of contact that recurrent decay will be all but impossible. It is for this reason that some dentists recommend porcelain as the restorative material of choice. While these restorations might be much more than fillings, the superiority of porcelain as a restoration in terms of resistance to occlusal forces, protection against recurrent decay, precision of fabrication, marginal integrity and many other aspects of restorative quality offers an excellent alternative to the regular fillings. For this reason, some patients request porcelain restorations so they can benefit from its wide range of advantages even when an amalgam or composite will suffice. The only true disadvantage of porcelain is the higher cost, which is offset by the quality to those who can afford it.