Hegelian Dialectic

Dialectic is a method of discussion between two arguments in an effort to finding a better truth and throughout histories, various philosophers have come up with their own logic of dialectic. Hegelian dialectic was born during the modern philosophy time, adopting Plato's dialectic with Hegel's own touch to it. Hegelian dialectic unites two different determinations into one, creating a meaning that, although the previous determination is negated, keeps the old concepts within it.
But how exactly is the Hegelian dialectic affecting the studies of logic and other subjects in the past? Also, how does Hegelian dialectic excels its predecessors, namely Plato's dialectic?