Porcelain is fused to an underlying metal structure to provide strength to a filling, crown or bridge. Alloy of gold, copper and other metals resulting in a strong, effective filling, crown or bridge. Alloys of non-noble metals with silver appearance resulting in high strength crowns and bridges.orcelain is fused to an underlying metal structure to provide strength to a filling, crown or bridge. Alloy of gold, copper and other metals resulting in a strong, effective filling, crown or bridge. Alloys of non-noble metals with silver appearance resulting in high strength crowns and bridges.
Limit refers principally to the establishment of a maximum beyond which a person or thing cannot or may not go: The Constitution limits the president's term of office to four years. To restrict is to keep within prescribed limits, as of choice or action: The sale of alcohol is restricted to people who are 21 and older.
boundary-a line determining the limits of an area. bound, edge. line-a length (straight or curved) without breadth or thickness; the trace of a moving point. rim-the shape of a raised edge of a more or less circular object.