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.
Three types of convergent boundaries are recognized: continentâcontinent, oceanâcontinent, and oceanâocean. Continentâcontinent convergence results when two continents collide. The continents were separated at one time by oceanic crust that was progressively subducted under one of the continents.