Obturation quality of calcium silicate-based cements placed with different techniques in teeth with perforating internal root resorption: a micro-computed tomographic study.

See more Silicon products. Silicon (atomic symbol: Si, atomic number: 14) is a Block P, Group 14, Period 3 element with an atomic weight of 28.085. The number of electrons in each of Silicon's shells is 2, 8, 4 and its electron configuration is [Ne] 3s² 3p². The silicon atom has a radius of 111 pm and a Van der Waals radius of 210 pm. Silicon was discovered and first isolated by Jöns Jacob Berzelius in 1823. Silicon makes up 25.7% of the earth's crust, by weight, and is the second most abundant element, exceeded only by oxygen. The metalloid is rarely found in pure crystal form and is usually produced from the iron-silicon alloy ferrosilicon. Silica (or silicon dioxide), as sand, is a principal ingredient of glass, one of the most inexpensive of materials with excellent mechanical, optical, thermal, and electrical properties. Ultra high purity silicon can be doped with boron, gallium, phosphorus, or arsenic to produce silicon for use in transistors, solar cells, rectifiers, and other solid-state devices which are used extensively in the electronics industry.The name Silicon originates from the Latin word silex which means flint or hard stone.

See more Calcium products. Calcium (atomic symbol: Ca, atomic number: 20) is a Block S, Group 2, Period 4 element with an atomic weight of 40.078. The number of electrons in each of Calcium's shells is [2, 8, 8, 2] and its electron configuration is [Ar]4s². The calcium atom has a radius of 197 pm and a Van der Waals radius of 231 pm. Calcium was discovered and first isolated by Sir Humphrey Davy in 1808. It is the fifth most abundant element in the earth's crust and can be found in minerals such as dolomite, gypsum, plagioclases, amphiboles, pyroxenes and garnets. In its elemental form, calcium has a dull gray-silver appearance. Calcium is a reactive, soft metal that is a member of the alkaline earth elements. It frequently serves as an alloying agent for other metals like aluminum and beryllium, and industrial materials like cement and mortar are composed of calcium compounds like calcium carbonate. It is also an biologically essential substance found in teeth, bones, and shells. The name "calcium" originates from the Latin word "calics," meaning lime.