Misc: In 1855, dentist Robert Arthur was the first to use ____ to fill cavities?

Questions

What type of shoes did Run-D.M.C. sing about, which were what most rappers in the early eighties were into?

What type of shoes were favored by skateboarders (Hint, it's 4 letterslong).?

What was the name of the multi-colored cube you had to re-organize?

What toy was in short supply for the 1983 Chirstmas season?

What mistake did Coca-Cola make in 1985?