Assessment of Gingival Reaction to Orthodontic Primer Application

Objective: after orthodontic bonding, some patients present a gingival hypertrophy. During the drying it may occur that primer flows in the sulcus. Orthodontic primers contains BIS-GMA, a xenoestrogen. In the human gingiva there are estrogen's receptors: their activation is involved in the gingival hypertrophy. The purpose of this study was to establish if gingival hypertrophy after the application of orthodontic brackets is only due to a different reaction to the plaque accumulation, or if some other factors intervene. Methods: the study group is composed by 60 patients, studied with a split-mouth and cross over design. Both the first dental hemiarchs, control side, was bonded usually; instead on the second side, test side, gingival sulcus was isolated with vaseline. Excess of primer was removed on both sides. At the beginning, at 1 month, at 3 months and at 6 months from the bonding were taken Bleeding index and Plaque index and photographs. Results: at the beginning patients don't show on probing neither plaque nor bleeding. At 1 month the presence of plaque and bleeding was the same in both sides, with no gingival hypertrophy. At 3 months indexes were regressed on the test side, while they were unchanged in the control side, where we found a mean of 2.9 teeth with gingival hypertrophy more than on the test side. At 6 months indexes was steady in the whole mouth, the mean difference of teeth with gingival hypertrophy in the control side face to the test side increased until 4.1. Conclusions: the gingival sulcus isolation during bonding wasn't enough to eliminate the appearance of some increase of gingival volume during the orthodontic treatment; the analysis of each mouth demonstrate that, with the same environment, the isolation of the sulcus was really effective on lowering this increase in a clinical significant manner.