Dedmon reacted angrily after being subbed out of the game, exchanging words with coaches, before storming off and flinging a massage gun back on to the court during play. The reserve center was ejected by officials for that act.
The Heat announced on Wednesday that in consultation with the NBA they had decided Dedmon would be banned for one game for "conduct detrimental to the team".
Miami head coach Erik Spoelstra had labelled the outburst as "unacceptable" after Tuesday's game.
"It's the Miami Heat. We're all a bunch of gnarly personalities," Spoelstra said.
"That part was unfortunate. Everything before that, that's the Miami Heat. That part was unacceptable."