Dental Filling, Crown and Bridge
Fillings
Cavities in teeth have been filled since earliest times with a variety of materials: stone chips, turpentine resin, gum, metals. Arculanus (Giovanni d'Arcoli) recommended gold-leaf fillings in 1484. The renowned physician Ambroise Paré (1510-1590) used lead or cork; in the 1700s, Pierre Fauchard (1678-1761), the father of modern dentistry, favored tin foil or lead cylinders; and Philip Pfaff (1715-1767), dentist to Frederick the Great of Prussia (1712-1786), used gold foil. Gold leaf as a filling became popular in the United States in the early nineteenth century; Marcus Bull of Hartford, Connecticut, began producing beaten gold for dental use in 1812 which was replaced in 1853 in the United States and England by sponge gold. This was followed by cohesive, or adhesive, gold introduced by American dentist Robert A. Arthur in 1855 and, by 1847, gutta percha was being used.
The invention of the power-driven dental drill led to increased demand for fillings and so for an inexpensive filling material. In 1826, Auguste Taveau of Paris, France, used silver coins to developed what was probably the first dental amalgam--a solution of one or more metals mixed with mercury. The French Crawcour brothers emigrated to the United States in 1833, introducing Taveau's amalgam; however, the poor quality of the amalgam led to its condemnation by many dentists, kicking off the so-called "amalgam war," a 10-year period from 1840 to 1850 of bitter controversy about the merits and deficiencies of mercury amalgam. Numerous experiments were made from the 1860s through the 1890s to develop improved amalgam filling materials, and Chicago, Illinois, dentist G. V. Black (1836-1915) finally standardized both cavity preparation and amalgam manufacture in 1895.
After truly effective dental cement was developed, baked porcelain inlays became popular for filling large cavities. These were first described by B. Wood in 1862. In 1897 an Iowa dentist, B. F. Philbrook, described his method of casting metallic fillings from a wax impression that matched the shape of the cavity perfectly. Dr. William H. Taggart of Chicago described a similar method for casting gold inlays in 1907. This technique made possible the modern era of accurate filling and inlay fitting. Amalgams--"silver fillings"--are still used, even though periodic controversies arise regarding the possibility of mercury toxicity. "White fillings," however, are gaining in popularity as they give a more aesthetic and natural look. Several types of cosmetic fillings are available today: Direct composites consist of quartz resin usually containing a light sensitive agent which allows them to be hardened, or bonded, into place by shining an intense light for about 40 seconds; indirect composite/porcelain inlays, specifically designed for strength as well as aesthetics, are usually fabricated in a laboratory then bonded in the dentist's office. Available in a variety of shades to match natural teeth, composites are extremely strong and can withstand the 40,000 pounds of pressure per square inch exerted when chewing with the back teeth.
Crowns and Bridges
Crowns (used to replace and cover missing portions of teeth) and bridges (mountings for artificial teeth anchored to and bridging the gap between the natural tooth at either side) were made of gold and used by the Etruscans at least 2,500 years before modern dentistry. Crowns and bridges fell from popularity during the Middle Ages and were only gradually rediscovered. The gold shell crown, described by Pierre Mouton of Paris, France, in 1746, was not patented until 1873 by Beers. The Logan crown, patented in 1885, used porcelain fused to a platinum post, replacing the unsatisfactory wooden posts previously used. In 1907 the detached-post crown was introduced, which was more easily adjustable. Bridge work developed along with crowns; dentists would add extra facing to a crown to hold a replacement for an adjacent missing tooth. The major advance came with the detachable facings patented by Dr. Walter Mason of New Jersey in 1890 and the improved interchangeable facings introduced by Mason's associate Dr. Thomas Steele in 1904. Today, crowns and bridges can be made from full porcelain, porcelain-fused-to-metal, polymer glass, or all metal. Cement and bonding materials for metal-free restorations--called adhesive dentistry--utilize zinc phosphate or glass ionometer cements. Cosmetic dentistry--reproducing a tooth for aesthetic reasons--is now popular and widely practiced: a dental implant is a metal screw placed into the jaw bone providing an anchor for a permanent false tooth or a set of false teeth; veneers are porcelain laminates which cover the natural tooth to mask and strengthen discolored or fractured teeth; and full caps (similar to crowns) are permanently placed over the original tooth to give an attractive appearance to a misshaped tooth or to narrow gaps between natural teeth.
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