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12 Dental Tribune Asia Pacific Edition | 7+8/2016 TRENDS & APPLICATIONS served. The procedure took ap- proximately 40 seconds to com- plete between lower left and right canine region. Results In this case, the mucosa turns pink without any signs of surface mucosal ablation except one spot between teeth 41, 42 (Fig. 9). Sub-surface coagulation of blood vessels gave a pink coloured ap- pearance. There was very mild post-op discomfort for about one hour after loss of the anaesthetic effect. No analgesics were re- quired as the discomfort feeling disappeared fast. Laser peeling of mucosa be- tween 31 and 41 was noted during photograph taking at one day post-op review (Figs. 10 & 11). The three day post-op photo taken by the patient showed that the laser peel disappeared with new gingi- val mucosa formation (Fig. 12). Two weeks post-op showed complete recovery of the gingival mucosa without melanin pigmentation (Fig. 13). Discussion There has not been much in- formation on this new wave- length. From Fig. 7, the absorption coefficient for haemoglobin is estimated at 7 x 10²/cm–1 and 10³/cm–1 for melanin. Penetration depth for haemoglobin is calcu- lated at 140 µm and 10 µm for mel- anin. The penetration depth of haemoglobin and melanin with 810 nm are 2 mm and 0.1 mm respectively. Furthermore, scat- tering curve showed less tissue scattering effect with 445 nm than 810 nm. In view of the low scattering effect together with high absorp- tion of haemoglobin and melanin to 445 nm, 1 W CW was used. Power density of 88 W/cm² (Fig. 14) deliv- ering at 88 J/cm² fluence at 2 mm distance was calculated. Although the power density of 1,697 W/cm² (Fig. 15) delivering 543 J/cm² flu- ence used by 810 nm is higher than 445 nm delivered, the eight years post-op showed stable gin- gival contour with no recession (Fig. 16). The understanding of the optical properties of the wave- length, power parameters and laser tissue interaction are impor- tant information for the clinician to achieve the desired treatment outcome. Conclusion The use of 1 W CW 445 nm blue diode laser is effective in non-ab- lative depigmentation of oral mu- cosa. This non ablative technique provide immediate aesthetic re- sult with very short procedure time. To the author’s knowledge, this is the first case presented using 445 nm for melanin depig- mentation. Editorial note: A list of references is available from the publisher. Dr Luk reports no potential conflicts of interest. Dr Kenneth Luk is a den- tal surgeon from Hong Kong. He can be contacted at laserdontic @me.com. 02 Accelerated type B cycle type B cycle 01 Intuitive user interface 03 Wi-Fi connection and Mobile App 04 Smooth external design Now available from your dental supplier or via wh.com New Lisa: Nothing compares to her AD Fig. 14: Diagram 3.—Fig. 15: Diagram 4. 14 15 1415