Reigning world champions Meryl Davis and Charlie White won their fourth straight US national ice dance title on Saturday in another dominant display. The couple's final score of 191.54 points was more than 12 points ahead of silver medalists Maia and Alex Shibutani, the world bronze medalists. Davis and White haven't lost a competition since they finished second to 2010 Olympic champions Tessa Virtue and Scott Moir of Canada at the 2010 world championships. They got the better of the Canadian duo at last year's world championships and in last month's Grand Prix finals. "Charlie and I feel really great about both of our performances here at nationals," Davis said. "We felt like we accomplished our goal for this competition, which was leaving it all out on the ice and feeling like we achieved a new comfort level with both programs as well as a higher level of performance." Ashley Wagner won the women's title with a sparkling free skate as other contenders faltered. Wagner, third after the short programme, led the free skate with 123.96 points for a winning total of 187.02 points. Skating after her, neither two-time champion Alissa Czisny nor Agnes Zawadzki -- the leader after the short programme -- could do better. Czisny, second after Thursday's short programme, was second in the free skate and took the silver medal with a total of 180.00 points. Zawadzki managed just the seventh-best free skate to claim the bronze with 174.10 points. Wagner's "Black Swan" free skate included a few mistakes, including failing to complete a triple salchow and double-footing a landing. However, on a night when none of the top women skated cleanly her artistically polished and emotionally dramatic performance stood out.