There is not much written about the kinds of retainers prescribed and how compliant patients are in using them according to Case Western Reserve's Manish Valiathan, an assistant professor of orthodontics and a member of the American Board of Orthodontics. This was noted as there is a dearth of information despite the devices being common in orthodontics practice.

Accordingly, Valiathan and fellow researchers started three studies that examined things like how people are using retainers, which types are prescribed and what happens when patients don't follow up orthodontic work with a retainer.

After randomly sending 2,000 surveys to orthodontists throughout the country, researchers received responses from 658 practitioners regarding the kinds of retainers they prescribe. The majority which was as high as 58.2 percent said that they prescribed removable retainers. On the other hand, about 40 percent opted for fixed lingual retainers that, once in place, are worn for life.

Post-braces, the majority of orthodontists said they required wearing removable retainers full-time for the first nine months and then part-time after that. They also encouraged part-time retainer use throughout life for their patients to make certain that the teeth remain in place.

Valiathan said that without retainers specific prior conditions may return and the whole treatment may fall flat. But that definitive research does not exist as to what conditions require ongoing retainer use. More evidence is needed, he said.