In Super Bowl VI, the Dallas Cowboys limited the Miami Dolphins to a mere 3 points. That's the only Super Bowl in which any team did not score a touchdown.
In fairness, we must give credit to the Dolphins in Super Bowl VII the following year. They kept the Washington Redskins' offense from scoring. Washington's only touchdown that day came on special teams. Late in that game, Miami kicker Garo Yepremian attempted to rescue a bobbled field goal with some kind of weird pass, which the Redskins' Mike Bass returned 49 yards for a TD.