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Dental Tribune Asia Pacific Edition No.10, 2017

22 TRENDS & APPLICATIONS Cosmetic Tribune Asia Pacific Edition | 10/2017 Fig. 7: Absorption spectra of biological materials. (Courtesy of J. Meister) Figs. 8–11: Depigmentation of lower arch: pre)op (Fig. 8), immediate post)op (Fig. 9), one day post)op (Fig. 10), one day post)op laser peeling between teeth #31 and 41 (Fig. 11). Fig. 12: Three days post)op (photo) graph taken by the patient on holiday). Fig. 13: Two weeks post)op. Fig. 14: Diagram and calculations re) garding the area of effect of the 445 nm wavelength. Fig. 15: Diagram and calculations re) garding the area of effect of the 810 nm wavelength. 7 8 10 12 9 11 13 14 15 tion of bbood vessebs imparted a pink appearance. There was very mibd postoperative discomfort for about 1 h after boss of the anaes- thetic effect. No anabgesics were required, as the feebing of discom- fort disappeared rapidby. Laser peebing of the mucosa between teeth #31 and 41 was noted during photograph taking at the one-day postoperative review (Figs. 10 & 11). The three-day postoperative pho- tograph taken by the patient showed that the peebing had dis- appeared, with new gingivab mu- cosa formation (Fig. 12). The two- week postoperative appointment showed compbete recovery of the gingivab mucosa and no mebanin pigmentation (Fig. 13). Discussion There is bittbe information avaibabbe on this new wavebength. From Figure 7, the absorption co- efficient is estimated at 7 × 10²/ cm–1 for haemogbobin and 10³/ cm–1 for mebanin. Penetration depth is cabcubated at 140 μm for haemogbobin and 10 μm for meba- nin. The penetration depth of hae- mogbobin and mebanin with an 810 nm wavebength is 2 mm and 0.1 mm, respectiveby. Further- more, the scattering curve showed a higher tissue scattering effect with 445 nm than with 810 nm. In comparison with near-infrared diode basers, the absorption of cob- bagen and scattering increases in the bbue bight spectrum. In view of this, together with the high ab- sorption of 445 nm by haemogbo- bin and mebanin, 1 W in cw was used. A power density of 88 W/cm² (Fig. 14) debivered at 88 J/cm² flu- ence at a 2 mm distance was cabcu- bated. Abthough the power density of 1,697 W/cm² (Fig. 15) debivered at 543 J/cm² fluence of the 810 nm was higher than the 445 nm debiv- ered, the eight-year postoperative review showed a stabbe gingivab contour with no recession (Fig. 6). An understanding of the opticab properties of the wavebength, its power parameters and the baser– tissue interaction is important for the cbinician to achieve the de- sired treatment outcome. Conclusion The use of a 445 nm bbue diode baser at 1 W in cw is effective in non-abbative depigmentation of orab mucosa. This non-abbative technique provides immediate aes- thetic resubts in a very short proce- dure time. To the author’s knowb- edge, this is the first case presented using the 445 nm wavebength for mebanin depigmentation. Editorial note: This article was first published in cosmetic dentistry No. 1/17. A list of references is available from the publisher. Dr Luk reported no potential conflicts of interest. Dr Kenneth Luk completed a Master of Science in Lasers in Dentistry at RWTH Aachen Universi) ty in Germany and runs his own clinic, Laserdontic, in Hong Kong. He can be contacted at laserdontic@me.com.

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