That remained the state of affairs until the late 1960s when Harald Loe ( at the time a professor at the Royal Dental College in Aarhus, Denmark ) demonstrated that a chlorhexidine compound could prevent the build-up of dental plaque.

The last of the Ainu households disappeared in the late 1960s, when Yamanaka Kitaro committed suicide after the death of his wife.

Aon was created in 1982, when the Ryan Insurance Group ( founded by Pat Ryan in the 1960s ) merged with the Combined Insurance Company of America ( founded by W. Clement Stone in 1919 ).

The region was a major producer of raw opium ( hence the name Afyon ) until the late 1960s when under international pressure, from the USA in particular, the fields were burnt and production ceased.

Remains of the walls of this fort were discovered west of the castle when excavating the foundations for a new post office and telephone exchange building in the late 1960s.

Burundi and Rwanda dispute sections of border on the Akanyaru / Kanyaru and the Kagera / Nyabarongo rivers, which have changed course since the 1960s, when the boundary was delimited ; cross-border conflicts among Tutsi, Hutu, other ethnic groups, associated political rebels, armed gangs, and various government forces persist in the Great Lakes region.

A comeback of sorts was seen during the 1960s and 1970s, but it was not until 1981, when the Liberals allied with the newly formed SDP to form the SDP-Liberal Alliance, that the party enjoyed significant electoral success.

Belief in conspiracy theories has become a topic of interest for sociologists, psychologists and experts in folklore since at least the 1960s, when the assassination of US President John F. Kennedy eventually provoked an unprecedented public response directed against the official version of the case as expounded in the Report of the Warren Commission.

One clear benefit of the ' late arrival ' of the channel was that its frequency allocations at each transmitter had already been arranged in the early 1960s, when the launch of an ITV2 was highly anticipated.

The line closed in the 1960s, when it became part of the Cheddar Valley Railway Nature Reserve.

The line closed in the 1960s, when it became part of the Cheddar Valley Railway Nature Reserve, and part of the National Cycle Network route 26.

This group sees mainland China as being similar to Franco's Spain in the 1960s, and South Korea during the 1970s when South Korea was run by corrupt, authoritarian regimes.

The craft remained primarily a homemaker's art until the late 1960s and early 1970s, when the new generation picked up on crochet and popularized granny squares, a motif worked in the round and incorporating bright colors.

In one 1960s comic, when Kent finds himself at a loose end when staff at the Daily Planet go on strike, he seriously considers it a chance to try out a new identity in case he has " to abandon Clark Kent role permanently.

Chelsea had their first major success in 1955, when they won the league championship, and won various cup competitions during the 1960s, 1970s, 1990s and 2000s.

In the late 1960s history repeated itself when Japanese firms started producing and exporting adding machines.

Modern disc golf started in the early 1960s, when it seems to have been invented in many places and by many people independently.

Music commented that Jones's death " hit so many people so hard " because " Monkees nostalgia cuts across generations: from the people who discovered the band during their original 1960s run ; to the kids who came of age watching 1970s reruns ; to the twenty-and thirtysomethings who discovered the Monkees when MTV ( a network that owes much to the Monkees ' influence ) began airing old episodes in 1986.

That changed, however, in the 1960s, when Benoît Mandelbrot started writing about self-similarity in papers such as How Long Is the Coast of Britain?

Since at least the 1960s, when Marc Bloch's Feudal Society ( 1939 ) was first translated into English in 1961, many medieval historians have included a broader social aspect that includes not only the nobility but all three estates of the realm, adding the peasantry bonds of manorialism and the estates of the Church ; this is sometimes referred to as " feudal society " since it encompasses all members of society into the feudal system.

During the 1960s, when some Virginia counties closed their public schools to avoid racial integration, compensatory private schooling was available only for Caucasian children.

The significant recoil of the M14 when fired in full-automatic mode was seen as a problem as it reduced accuracy, and in the 1960s it was replaced by Eugene Stoner's AR-15, which also marked a switch from the powerful. 30 caliber cartridges used by the U. S. military up until early in the Vietnam War to the much less powerful but far lighter and light recoiling. 223 caliber ( 5. 56mm ) intermediate cartridge.

The image of the gnome changed further during the 1960s to 1970s, when the first plastic garden gnomes were manufactured.

However, the overdriven sound of the Hammond gained a new image when it became part of 1960s and 1970s rock with artists like Alan Price, Gregg Allman, Steve Winwood, Rick Wright, Keith Emerson, Jon Lord, Matthew Fisher, Rick Wakeman, Tony Banks and Jack McDuff.

Airport construction boomed during the 1960s with the increase in jet aircraft traffic.

The early 1960s also saw the introduction of jet bridge systems to modern airport terminals, an innovation which eliminated outdoor passenger boarding.

In the early 1960s, the company introduced the C-141 Starlifter four-engine jet transport.

The company continued building jet engines, under licence, for the RCAF from Avro and Canadair Aircraft Ltd in the 1960s.

Likewise, celestial navigation was used in commercial aviation up until the early part of the jet age ; it was only phased out in the 1960s with the advent of inertial navigation systems.

A number of jet interceptors such as the F-102 Delta Dagger, the F-106 Delta Dart, and the MiG-25 were built in the period starting after the end of World War II and ending in the late 1960s, when they became less important due to the shifting of the strategic bombing role to ICBMs.

Turbofan aircraft began entering service in the 1950s and 1960s, and this is the most common type of jet in use today.

After initial training in a Cessna T-41 at an offsite location ( e. g., Eloy, AZ was used in the late 1960s ), the first jet flight was largely a ' demo ' flight in the T-37 aircraft with the instructor orienting the student to the aircraft, the local training area, and some basic flight maneuvers.

When these high bypass jet engines reached commercial service in the 1960s, subsonic jet engines immediately became much more efficient, closer to the efficiency of turbojets at supersonic speeds.

For a period of time in the 1960s, Convair manufactured its own line of jet commercial airliners, the Convair 880 and Convair 990, but this did not turn out to be a profitable business.

The light jets have been a staple of the business jet industry since the advent of the Learjet 23 in the early 1960s.

In the early 1960s, when commercial jet airline service came to Orlando, the installation became a joint civil-military facility.

Following the mid-to late 1960s ' introduction by Pan American World Airways ( Pan Am ) and British European Airways ( BEA ) of jet aircraft with short-field capabilities that were not payload-restricted on Tempelhof's short runways, Air France experienced a traffic decline on those routes where it competed with Pan Am and BEA, mainly as a result of Tegel's greater distance and poorer accessibility from West Berlin's city centre.

By the mid 1960s the airport commenced seeing its first domestic pure jet engine aircraft, commencing with a Boeing 727 in 1964, and the Douglas DC-9 in 1967, both types operated by TAA and Ansett ANA.

Continental and Trans-Texas both introduced DC9 jet flights in the late 1960s.

With the advent of large passenger jet aircraft in the 1960s, intercontinental travelers largely switched from ships to planes, sending the ocean liner trade into a slow decline.

World entered the jet era in the late 1960s with Boeing 707s and 727s.

The jet age came to Legazpi in the late 1960s and by the ' 70s Philippine Airlines ( PAL ) introduced regular service to / from Manila using British Aircraft Corporation's BAC 1-11's.

In the late 1960s, the RHAF acquired new jet aircraft, that served well for almost 20 years.

* Aero L-29 Delfín ( Czech: " Dolphin "), a military jet trainer aircraft of the 1960s

Fighter-bombers became increasingly important in the 1950s and 1960s, as new jet engines dramatically improved the power of even the smallest fighter designs.

** F-6 Skyray, a 1950s / 1960s US Navy jet fighter

He was an advocate of maneuverable fighter aircraft, in contrast to the heavy, powerful jet fighters that were prevalent in the 1960s, such as the F-4 Phantom II and General Dynamics F-111.