If a tooth with a gold crown breaks, it is generally because the underlying tooth structure has fractured or decayed. Gold crowns are not immune to becoming loose, especially if you are eating foods and candy that are harmful to crowns and bridges. Gold crowns also cause the least wear on the opposing tooth.
Making the world better, one answer at a time. An artificial boundary is a boundary made by humans, examples include dams, the fence at the border between the U.S and Mexico. A natural boundary is a boundary made by nature, a boundary that happens naturally, examples include rivers, mountains and such.
The boundary of an area of land is an imaginary line that separates it from other areas. ...the Bow Brook which forms the western boundary of the wood. Drug traffickers operate across national boundaries. The boundaries of something such as a subject or activity are the limits that people think that it has. The boundaries between history and storytelling are always being blurred and muddled. ...extending the boundaries of press freedom. Synonyms: limits, bounds, confines, threshold More Synonyms of boundary.