Gingival response to removable orthodontic appliances.

The gingival state of twenty-four young patients (mean age 9.4 years) wearing simple removable orthodontic appliances was assessed and followed at monthly intervals for 4 months. In nine of the patients intentional relief of the appliance was made in the upper right area. The plaque index levels were similar in both "relief" and "no-relief" groups and reached a similar score at 4 months. The gingival index was significantly higher in the "relief" group, and all five cases that showed gingival hyperplasia of the experimental area belonged to this group.