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

2025-09-30
BMC research notes 18(1)
- Manal M Al-Hajri
- Abdulaziz M Tawfik
- Redhwan Saleh Al-Gabri
- Sadam Ahmed Elayah
- Ahmed Yaseen Alqutaibi

PubMed: 41029860
DOI: 10.1186/s13104-025-07476-w

Study Design

Type: Randomized Controlled Trial (RCT)
Population: 20 healthy patients aged 19-36
Methods: Randomized split-mouth design, vitamin C injections (group 1) on one side and scalpel surgery (group 2) on the other side of the maxilla
Duration: 6 months

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.

Research Insights

Vitamin C→Reduced Dummett Oral Pigmentation Index
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).
Effect
Neutral
Effect size
Small
Vitamin C→Reduced Gingival Pigmentation Index
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)
Effect
Neutral
Effect size
Small
Vitamin C→Reduced Itching
The vitamin C group reported lower pain and itching levels (itch: P = 0.02)
Effect
Beneficial
Effect size
Small
Vitamin C→Reduced Melanin Pigmentation Index
The GPI, MPI, and DOPI showed no significant differences in pigmentation between the groups at baseline and after six months (P = 1.00 and 0.54 for MPI)
Effect
Neutral
Effect size
Small
Vitamin C→Reduced Oral Pigmentation Index
The GPI, MPI, and DOPI showed no significant differences in pigmentation between the groups at baseline and after six months (P = 1.00 and 0.59 for DOPI)
Effect
Neutral
Effect size
Small
Vitamin C→Reduced Pain
The vitamin C group reported lower pain and itching levels (pain: P = 0.00)
Effect
Beneficial
Effect size
Small

Adverse Events Reported

Vitamin C→itching
The vitamin C group reported lower pain and itching levels (itch: P = 0.02; pain: P = 0.00).
Finding
No significant difference
Magnitude
itch: P = 0.02
Significant
Yes
Vitamin C→pain
The vitamin C group reported lower pain and itching levels (itch: P = 0.02; pain: P = 0.00).
Finding
No significant difference
Magnitude
pain: P = 0.00
Significant
Yes