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ePaper created 2016-04-05, 13:01:42 | version 1.38.0
24 laser 1 2016 | case report Non-ablative melanin depigmentation of gingiva Author: Dr Kenneth Luk, Hong Kong Fig. 1: Depigmentation by ablation. Fig. 2: Depigmentation by absorption of melanin and haemoglobin. Introduction Melanin depigmentation of gingiva using vari- ous laser wavelengths have been reported for over ten years.1–5 Layer by layer, the mucosa is ablated to the basal layer of the epithelium where the me- lanocytes are located. The use of lasers have been compared with the use of scalpel and diamond bur (Fig. 1).6–9 By incorporating the optical properties and absorption characteristics of 810 nm together with specific power parameters, a non ablative technique was developed (Fig. 2).10, 11 Another similar non-ablative technique de- scribed as microcoagulation was also reported using a 20 W 980 nm diode laser.12 The 445 nm blue wavelength was introduced in the dental market in 2015. By using 320 μm uninitiated fiber delivering 1 W continuous wave of 445 nm, the same non-ablative procedure and result can also be realized. Background with non-ablative technique Diode laser at 810 nm is poorly absorbed in water, but it is well absorbed by pigment such as haemoglobin and melanin. The use of high power, short pulse duration concentrated the thermal energy on the surface over deep tissue thermal conduction with lower power and long pulse.13, 14 The author has used the 810 nm wavelength ( elexxion Claros 810 nm diode laser, elexxion AG, Singen, Germany) with the power parameters of 30 W, 20 kHz, 16 μsec giving an average power of 10 W. Under local anaesthesia, a non-initiated 600 μm fiber was used. The fiber was placed at a distance of 2 mm to 5 mm from the pigmented mucosa. Coagulation can be observed with im- mediate effect upon irradiation. A constant movement must be performed in order to avoid thermal damage deep into the tis- sue. Water irrigation can be used as coolant Fig. 2 Fig. 1 12016