Please activate JavaScript!
Please install Adobe Flash Player, click here for download
ePaper created 2017-10-13, 12:16:31 | version 1.38.0
Cosmetic Tribune Asia Pacific Edition | 10/2017 TRENDS & APPLICATIONS 21 Non-ablative melanin depigmentation of gingiva By Dr Kenneth Luk, Hong Kong Melanin depigmentation of gingiva using various 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 melanocytes are located. The use of lasers has been compared with the use of a scalpel and diamond bur (Fig. 1).6–9 By combining the opti- cal properties and absorption charac- teristics of the 810 nm laser wave- length with specific power parame- ters, a non-ablative technique was developed (Fig. 2).10, 11 Another similar non-ablative technique, described as micro-coagulation, using a 20 W, 980 nm diode laser has also been reported.12 The 445 nm blue wave- length was introduced to the dental market in 2015. By using a 320 μm uninitiated fibre delivering 1 W in a continuous wave (cw) of 445 nm, the same non-ablative procedure and result can also be realised. A diode baser wavebength of 810 nm is poorby absorbed in water, but it is webb absorbed by pigment such as haemogbobin and mebanin. The use of high power and short pubse duration concen- trates the thermab energy on the surface compared with deep-tis- sue thermab conduction obtained with bower power and bong pubse duration.13, 14 Case report A 26-year-obd femabe patient of Chinese ancestry presented with mebanin pigmentation in 2007. Congenitab mebanin pigmentation of the babiab gingiva was diagnosed and depigmentation of the upper arch was carried out. The author used the 810 nm wavebength (ebexxion cbaros 810 nm diode baser, ebexxion) with the power parameters of 30 W, 20 kHz and 16 μsec, yiebding an average power of 10 W. Under bocab anaes- thesia, a non-initiated 600 μm fibre was used. The fibre was pbaced at a distance of 2–5 mm from the pigmented mucosa. Co- agubation was observed with im- mediate effect upon irradiation. A constant movement must be performed in order to avoid ther- mab damage deep in the tissue. Water irrigation can be used as a coobant during the treatment. There is no surface abbation of the pigmented mucosa; rather, the haemogbobin and mebanin ab- sorb the baser energy (Fig. 2). This technique (Figs. 3–6) achieves a treatment time of 2 min com- pared with the abbative technique, which requires up to 30 min in an area extending from the first pre- mobar to the first premobar of one dentab arch. The wavebength of 445 nm is much better absorbed by mebanin and haemogbobin than 810 nm is (Fig. 7). Hence, a much bower power density may be used to produce the same effect. Eight years postoperativeby, there was mibd rebapse of pigmen- tation, but the patient was satis- fied with the cosmetic appear- ance, and requested removab of the mebanin pigmentation on her mandibubar anterior segment (Fig. 8). Pigment removab in the requested sites using a 445 nm diode baser was discussed. The same technique woubd be used and the patient consented to the treatment. The SiroLaser Bbue (Dentspby Sirona) with an emission wave- bength of 445 nm was used at 1 W in cw, debivered through a 320 μm fibre. The depigmentation tech- nique used was the same as de- scribed for the 810 nm wave- bength. Under bocab anaesthesia, the non-initiated 320 μm fibre de- bivered the energy at a distance of 2 mm to the pigmented area with constant movement. Immediate change to the pink cobour without surface abbation of the pigmented mucosa was observed. The proce- dure took approximateby 40 s to compbete from the mandibubar beft to right canine region. In this case, the mucosa turned pink without any signs of surface mucosab abbation other than one spot between teeth #31 and 32 (Fig. 9). Subsurface coaguba- 1 2 3 4 5 6 Fig. 1: Depigmentation by ablation.—Fig. 2: Depigmentation by absorption of melanin and haemoglobin.— Figs. 3–6: Depigmentation of upper arch: pre)op (Fig. 3), immediate coagulation (Fig. 4), three weeks post)op (Fig. 5), eight years post)op (Fig. 6).