1930–1943—Frederick S. McKay, a Colorado dentist, is convinced that brown stains (mottling) on his patients’ teeth are related to their water supply. McKay’s research verifies that drinking water with high levels of naturally occurring fluoride is associated with low dental caries and a high degree of mottled enamel. By the early 1940s, H. Trendley Dean determines the ideal level of fluoride in drinking water to substantially reduce decay without mottling.
1938—The nylon toothbrush, the first made with synthetic bristles, appears on the market.
1937—Alvin Strock inserts the first Vitallium dental screw implant. Vitallium, the first successful biocompatible implant metal, had been developed a year earlier by Charles Venable, an orthopedic surgeon.
1945—The water fluoridation era begins when the cities of Newburgh, New York, and Grand Rapids, Michigan, add sodium fluoride to their public water systems.
1948—President Harry S. Truman signs the Congressional bill formally establishing the National Institute of Dental Research and initiating federal funding for dental research. The name changes to National Institute of Dental and Craniofacial Research (NIDCR) in 1998.
1950s—The first fluoride toothpastes are marketed.
1949—Oskar Hagger, a Swiss chemist, develops the first system of bonding acrylic resin to dentin.
1955—Michael Buonocore describes the acid etch technique, a simple method of increasing the adhesion of acrylic fillings to enamel.
1957—John Borden introduces a high-speed air-driven contra-angle handpiece. The Airotor obtains speeds up to 300,000 rotations per minute and is an immediate commercial success, launching a new era of high-speed dentistry.
1957 —The Social Security Act is amended to include self-employed dentists.
1958—A fully reclining dental chair is introduced.
1960s—Sit down, four-handed dentistry becomes popular in the U.S. This technique improves productivity and shortens treatment time.
1960s—Lasers are developed and approved for soft tissue procedures.
1960—The first commercial electric toothbrush, developed in Switzerland after World War II, is introduced in the United States. A cordless, rechargeable model follows in 1961.
1962—Rafael Bowen develops Bis-GMA, the thermoset resin complex used in most modern composite resin restorative materials.
1980s—Per-Ingvar Branemark describes techniques for the osseointegration of dental implants.
1989—The first commercial home tooth bleaching product is marketed.
1990s—New tooth-colored restorative materials plus increased usage of bleaching, veneers, and implants inaugurate an era of esthetic dentistry.
1997—FDA approves the erbium YAG laser, the first for use on dentin, to treat tooth decay.