Gingival depigmentation by conservative injectable vitamin C in comparison with scalpel surgery: a randomized controlled split-mouth clinical trial.

Background: Gingival pigmentation (GP) is a common aesthetic concern in dentistry. While GP is not harmful, it can cause psychological distress. This study aimed to evaluate the efficacy of vitamin C injection for managing GP compared to the standard scalpel surgery.

Methods: The study involved 20 healthy patients aged 19-36. A randomized split-mouth design was used, with vitamin C injections (group 1) on one side and scalpel surgery (group 2) on the other side of the maxilla. Clinical evaluations of gingival depigmentation were conducted preoperatively and at first, second, three weeks and six months postoperatively, using the Gingival Pigmentation Index (GPI), Melanin Pigmentation Index (MPI), Dummett Oral Pigmentation Index (DOPI) and Color Intensity Analysis using ImageJ. Pain and patient satisfaction were measured with a visual analogue scale (VAS) after treatment.

Results: The GPI, MPI, and DOPI showed no significant differences in pigmentation between the groups at baseline and after six months (P = 1.0 and 0.80 for GPI; P = 1.00 and 0.54 for MPI; P = 1.00 and 0.59 for DOPI). However, after three weeks, greater depigmentation was noted on the surgical side. The vitamin C group reported lower pain and itching levels (itch: P = 0.02; pain: P = 0.00).

Trial registration: This randomized controlled trial was retrospectively registered in the Thai Clinical Trial Registry at 05-7-2024 ( www.thaiclinicaltrials.org ), and its registration number is TCTR20240715003.