"Particularly we recommend electric toothbrushes when people have a history of periodontal disease, or gum disease," said Dr. Steven Abel.
Consumer Reports tested 10 electric toothbrushes, brushing almost 2,000 times to find the best.
"One convenience of many electric toothbrushes is that they have built-in timers that signal after two minutes," said Amy Keating of Consumer Reports.
Some also alert you when 30 seconds are up. That's when it's time to move to the next quadrant of your mouth.
The panelists used each toothbrush for a week, and at the end of the week, they refrained from brushing for 24 hours to build up plaque. Then a dentist used a red dye to determine how much plaque was left.
The brushes range in price from $15 to $140. Panelists found some worked very well, and others actually hurt their gums.
One of the top-rated toothbrushes, a $140 Philips Sonicare Flexcare, removed more than 75 percent of plaque. It has three cleaning modes - clean, sensitive and massage.
But some panelists found the Philips Sonicare uncomfortable.
"I kept looking at the time ... because it was hurting so bad. It was just too much vibration," said panelist Antonietta Maggiacomo.
Panelist Alex Willen said the toothbrush "tickled" his gums a little bit.
Most panelists preferred a less expensive Oral-B toothbrush. Consumer Reports says a good one to try is the Oral-B Professional Care 1000 for $70.
The Oral-B Professional Care 1000 is also sold under the name Oral-B Professional Care 7400.