cosmetic dentistry_ beauty & science

industry report _ lasers I Fotona lasers, for example) are the only option without raising a flap. Toothpreparationforcrownsandbridgeswith lasers is not yet as efficient as one might like it to be; however, new research and technological im- provements are ongoing. A diode or Nd:YAG laser can still be helpful during prosthetic work for troughing before taking impressions or desensi- tising prepared teeth if required. It is also possible to reduce or eliminate dentine hypersensitivity due to periodontal treatment or gingival reces- sion by either modulating the nerve endings or blocking the dentinal tubules using a laser. Another aesthetic treatment is gingival depig- mentation (Figs. 2a & b), which can also be per- formed by using long pulses of erbium or diode lasers.Itispossibletode-epithelialisethesurface, as the pigmentation is usually in the basal layer. Erbium lasers are safer, since they do not pen- etratethetissue.Theeffectisonlysuperficial,and this is exactly where the pigmentation is. Diode lasers penetrate more deeply, especially if one is not careful and tries to remove tissue that is lighter in colour. As with other treatments, erbium lasers allow the tissue to heal faster; however, there can be mild bleeding during the operation. Class V caries removal for composite fillings can easily be performed with an erbium laser, quickly, painlessly, and without any thermal side- effects, especially if the pulse durations are short enough—typically between 50 and 100 micro- seconds (Fig. 3). The shorter the pulse duration is, the more effective the laser energy will be at re- moving hard tissue. The margins of the cavity can even be bevelled for better aesthetic appearance and long-term colour stability if the laser is effi- cient enough to remove small amounts of sound enamel when needed. Lasers also work selectively to only remove carious tissue, which has more water content than sound hard dental tissue. Surface modifica- tion can also be done with the erbium laser after cavity preparation for repairing composite fill- ings, or even for restoration cementation. One big advantage is that anaesthesia is not generally required when bloodless gingivectomy is used to uncover the borders of the carious lesion with an erbium laser using pulse durations of between 600 and 1,000 microseconds (Figs. 4a & b). Fig. 3_SEM image of hard dental tissue after ablation with an erbium laser. Figs. 4a & b_Clinical case before treatment (a). Immediately after gingivectomy and carious lesion removal (b). Figs. 5a & b_Before (a) and after TouchWhite procedure (b). I 31cosmeticdentistry 1_2013 Fig. 3 Fig. 5a Fig. 5b Fig. 4a Fig. 4b