was the Cuban Missile Crisis a turning point in relations between the superpowers?

Answer 1

and to expand on TG's point::

powers, especially Russia, had no problem over the centuries with the concept that war was an acceptable last resort to a diplomatic crisis.
The Soviet Union had just finished WW2 where it lost 20,000,000 dead and came out as the world's number 2 power.

But the Cuban Crisis was the first crisis of the nuclear age......all of a sudden, world leaders, esp the Sovs had to look at a scenario where 200,000,000 million dead, not just 20, would be the result of a nuclear exchange.
This lead directly to MAD...Mutually Assured Destruction.....and while there were a lot of perimeter and proxy wars, we never did have an all out WW 3.......

Answer 2

Yes. After the crisis both sides realised how close they had come to nuclear war, and the unacceptable consequences of that war. That realisation led directly to the establishment of a direct telephone line between the Kremlin and the White House, called the Hot Line. It was the beginning of the opening of limited dialogue between the USSR and USA in international affairs.

Answer 3

The Soviet Union tended to think of the US as pampered and weak. After the Cuban Missile Crisis, they realized that the US would stand up to them even to the point of war. It made them much more cautious.