The present study evaluated and compared surgical stripping, rotary, electrocautory and diode laser techniques for gingival depigmentation. The clinical outcomes of the treatment modalities were compared in terms of pain perception using VAS scores, DOPI scores at baseline and 6 months post operatively and patient preference for treatment type based on overall experience.

In the present study, VAS was selected for the estimation of pain perception, as VAS seems to assess more closely what a patient actually experiences with respect to change in pain intensities and is highly sensitive with a discriminating capacity superior to other scales. The least amount of pain was experienced after treatment with the InGaAsP laser followed by electrocautory, scalpel and rotary. Comparatively less pain in InGaAsP laser group could be explicated by its ability to disrupt Na+-K+ pump in the cell membrane, resulting in inhibition of impulse conduction.  Electrocautory assisted depigmentation results protein coagulum formation on the wound surface, which acts as a biologic dressing thus patient experience minimal pain.  This is in contrast to the surgical stripping and rotary procedure, which results in a raw, bleeding surface, with exposed nerve endings leading to greater postoperative pain, depending on depth of the connective tissue exposed and the patient’s pain threshold. The results of the present study are in corroboration with previous studies which showed lasers possess added advantage of analgesic effect enhancing patient acceptance and compliance compared to surgical stripping or rotary.   

Patients were recalled after one week to evaluate the healing process. Healing was found to be satisfactory for all the groups except for slight delay in the healing with respect to electrocautory group. Scalpel and rotary assisted depigmentation results in exposure of connective tissue bed, which is exclusively based on tactile sensation, hence depth of tissue penetration and wound size can be minimized. Diode lasers are known for limited tissue penetration compared to other lasers.  Tissues with higher pigmentation are relatively more sensitive to laser absorption than tissue with minimal or no pigmentation due to the presence of chromophores such as melanin, thus resulting in reducing the operating site and faster healing. The depigmentation with electrocautory is performed using the sides as well as the tip of the electrode and thus it may inadvertently damage the adjacent tissues resulting in delayed wound healing.  The findings of the present study are in comparison with by previous studies by Shalu Chandna et al and Bhusari et al. 

The treated sites were observed periodically for signs of repigmentation. Various factors are involved in recurrence of physiologic pigmentation, such as treatment modalities, duration of follow-up, exposure to ultraviolet rays and habits like smoking.  Intensity of clinical repigmentation also depends on the number and functional activity of melanocytes. In the present study, at the end of six months 10% of Laser ,15% of electrocautory, 25% rotary and 30% scalpel treated group showed repigmentation with DOPI score of 1 (mild clinical pigmentation), which is aesthetically acceptable. The lower percentage of repigmentation with Laser and electrocautory as compared to scalpel and rotary could be elucidated with following reasons. Laser assisted tissue ablation results in thermal damage to melanocytes and electrical energy used in electrocautory leads to the molecular disintegration of melanin cells of the operated and surrounding sites. Thus, has a strong influence in retarding migration of melanin cells. On the other hand, the surgical stripping or rotary method offers benefits of tactile sensation and no risk of thermal damage to the underlying structures, however incomplete depigmentation may result in migration of the melanocytes from non-operated sites to the operated sites. 

Gingival depigmentation may not be considered completely successful if the treatment is not patient perceptive. Hence in the present study patients were asked to rate the treatment modality based on overall outcome. Laser group was the most preferred treatment modality by major group of patients, followed by rotary, scalpel and then electrocautory. Patients who preferred Laser, expressed that there was no or minimal pain during or after the procedure, shorter operating time and minimal bleeding. On other hand although electrocautory demonstrated effective aesthetic outcome and analgesic effects, patients complained about unpleasant odour throughout procedure and delay in wound healing was also noted.