Although physiologic gingival hyperpigmentation is not a pathologic condition, it is considered one of the main esthetic problems in dentistry. It was found that the attached gingiva is the most frequently pigmented intraoral tissues followed by the papillary gingiva and the alveolar mucosa

In addition to all of the previously mentioned actions of vitamin C, it was found to be involved in depigmentation due to several factors that not only depend on its direct effect on melanin and melanocytes but also due to the overall effect on the applied tissues. Melanin is one of the main reservoir for ROS, copper and calcium in the tissue cells . Once vitamin C is introduced to the target tissue, it binds efficiently to melanin due to the ROS, calcium and copper content which causes intracellular deficiency of these items and the inability of the cells to produce melanin. Calcium deficiency causes failure of melanocytes to perform cellular adhesion to keratinocytes as calcium is essential to form cadherins . Adhesion to keratinocytes is important stimulator to melanocytes in order to produce melanin, format dendrites and transfer the produced melanin to neighboring cells . Shortage of the intercellular copper limits the formation of tyrosin, tyrosinase enzyme and peroxidase enzyme which in turn stops the melanin production .

Therefore, the aim of the present study is to compare the clinical efficiency of the non-surgical intraepidermal injection of vitamin C in comparison to the gold standard surgical technique (scalpel technique) for gingival depigmentation.

Inclusion Criteria:

• aged 18-50 y
• medically free;
• physiologic gingival hyperpigmentation related to esthetic region were selected.

Exclusion Criteria:

All the reasons that could provoke an inflammatory reaction were excluded such as:

• systemic diseases (especially auto-immune diseases and chemotherapy uptake);
• pregnant and lactating mothers;
• usage of chlorhexidine or povidone iodine;
• Local causes (smoking and periodontitis).