The answer would depend on what time period you consider. If you consider a period of less than twelve years, then the answer is yes. If you are looking for a longer time period, the answer is the 49ers. In any case, when considering dynasties, there are only two possible answers: Patriots and 49ers. All this according to Nate Silver.
http://fivethirtyeight.com/datalab/patriots-nfl-dynasty-greatest-of-all-time/
"New England Patriots quarterback Tom Brady grew up in the San Francisco Bay Area idolizing Joe Montana, Steve Young and the San Francisco 49ers. Now, after winning his fourth Super Bowl on Sunday, Brady has helped the Patriots cement their place alongside the 49ers among the top NFL dynasties of all time.
Whether the Patriots or the 49ers rank as the top modern NFL dynasty depends on the length of the period you consider. In the chart below, I’ve measured the top franchises over periods ranging from one year to 25 years.1 Rankings are based on a team’s average Elo rating at the end of each season. (We’ve calculated Elo ratings back to the AFL-NFL merger year of 1970, so great teams before that — like the Green Bay Packers of the 1960s — are not considered.)
•The Patriots rate as having the best five- and six-year runs;
•The 49ers have the best seven- and eight-year stretches;
•The Patriots then overtake the Niners as the best dynasty for periods of nine through 12 years;
•But the 49ers win again for periods of 13 years and longer."
http://fivethirtyeight.com/datalab/patriots-nfl-dynasty-greatest-of-all-time/
"New England Patriots quarterback Tom Brady grew up in the San Francisco Bay Area idolizing Joe Montana, Steve Young and the San Francisco 49ers. Now, after winning his fourth Super Bowl on Sunday, Brady has helped the Patriots cement their place alongside the 49ers among the top NFL dynasties of all time.
Whether the Patriots or the 49ers rank as the top modern NFL dynasty depends on the length of the period you consider. In the chart below, I’ve measured the top franchises over periods ranging from one year to 25 years.1 Rankings are based on a team’s average Elo rating at the end of each season. (We’ve calculated Elo ratings back to the AFL-NFL merger year of 1970, so great teams before that — like the Green Bay Packers of the 1960s — are not considered.)
•The Patriots rate as having the best five- and six-year runs;
•The 49ers have the best seven- and eight-year stretches;
•The Patriots then overtake the Niners as the best dynasty for periods of nine through 12 years;
•But the 49ers win again for periods of 13 years and longer."