Hyaluronic acid vs. physiological saline for enlarging deficient gingival papillae: a randomized controlled clinical trial and an in vitro study

BACKGROUND: loss of the interdental papillae leads to the formation of a black triangle, which compromises smile esthetics and contributes to food impaction and plaque accumulation. The aim of this study was to evaluate the efficacy of the injection of hyaluronic acid (HA) and compare it to that of physiological saline solution in the restoration of deficient gingival papillae in vivo and in vitro. METHODS: Twenty-four patients with 68 deficient gingival papillae were recruited for this clinical trial with a split-mouth design. The deficient gingival papillae on one side of the anterior maxilla were injected with HA, and those on the other side were injected with physiological saline solution. The heights of the gingival papillae and the areas of the black triangles were measured from clinical photographs obtained before and 6 and 12 months after treatment. Additionally, the proliferation and migration of gingival fibroblasts were evaluated after HA and physiological saline treatment by an in vitro study. RESULTS: the results revealed that the injection of HA yielded 0.198 and 0.28 mm gingival papilla increasement at 6 and 12 months, respectively, relative to the baseline (P<0.05). However, deficient gingival papillae also grew by 0.278 mm at 12 months in the group that received physiological saline solution (P<0.05). The injection of HA significantly improved deficient gingival papillae 6 months earlier than the injection of physiological saline solution. HA also significantly accelerated the proliferation and migration of gingival fibroblasts in vitro. CONCLUSIONS: The present study confirms that the injection of HA could increase the height of gingival papillae for improving gingival papilla defects. However, the effect is not superior to that of physiological saline solution. This trial was registered in the Chinese Clinical Trial Registry (ChiCTR-ONC-17011781) (28/06/2017). http://www.chictr.org.cn/showproj.aspx?proj=19931