Support: Introduction Methodology Results Conclusions References Dental bleaching efficacy with light application: in vitro study Vitor Hugo Panhóca1, Bruno Pereira de Oliveira, Vanderlei Salvador Bagnato São Carlos Institute of Physics – University of São Paulo – São Carlos, SP, Brazil e-mail: vhpanoca@ifsc.usp.br1 http://www.cepof.ifsc.usp.br/ Introduction Figure 4: Blue Intensity (%) in the bovine teeth impregnated with coffee, before and after treatment with a violet light (photobleaching). Before Bleaching (BB); After Bleaching (AB); Photobleaching (Violet light LED with Coffee) Dental bleaching is a cosmetic procedure done very often in dental offices. Tooth whitening has been the subject of several studies. However, studies had been showed controversial results about the use of light in the teeth bleaching in comparison with peroxide hidrogen gel procedure. The objective of this study was to determine the influence of light irradiation protocol about getting better cosmetic results using colorimetric spectrophotometer, which measure color changes. Pump,  =1900 nm Methodology A B Were selected 12 bovine tooth and were splited in 2 parts (Figure 1). Six tooth were putted in coffee solution during 30 hours (Figure 1B). Firstly, the left side of all tooth received treatment with peroxide hidrogen gel in 35% concentration, during 40 minutes. After this, the right side of all tooth received treatment with violet light LED (photobleaching; 410±10 nm; 20 applications of 30 seconds with interval of 1 minute) totalizing 30 minutes (Figure 2). A commercial spectrophotometer was used to measure the color changes before and after the treatments. Figure 1: A-) Bovine teeth without coffee solution B-) Bovine teeth with coffee solution. Figure 5: Blue Intensity (%) in the bovine teeth without coffee. PB (Photobleaching); DB (Dental Bleaching) Photobleaching versus Gel Dental Bleaching (without Coffee) A B Figure 2: Experimental Design : A) Violet light application; B) Traditional dental bleaching with peroxide hidrogen gel in 35% concentration. Results Photobleaching (Violet light LED) Figure 6: Blue Intensity (%) in the bovine teeth with coffee. PB (Photobleaching); DB (Dental Bleaching) Conclusions The results showed that the violet light have broken the pigments in dental surface. Therefore, it’s necessary to performed an analyses statistical to confirm if doesn’t differences between the treatments. Figure 3: Blue Intensity (%) in the bovine teeth before and after treatment with a violet light. Before Bleaching (BB); After Bleaching (AB); References Support: 1) Buchalla W, Attin. External bleaching therapy with activation by heat, light or laser – A systematic review. Dent. Mater. 2007. , 23(5), 586-596. 2) Florez, FE, Andrade, MF, Campos, EA, Oliveira, JO, Bagnato, VS, Panhoca, VH. In-office dental bleaching efficacy assessment in function of the light exposure regime by digital colorimetric reflectance spectroscopy. Journal of Dentistry and Oral Hygiene. 2011. 3(8), 99-105. 3) Wetter NU, Barroso MCS, Pelino JEP. (2004). Dental Bleaching Efficacy with Diode Laser and LED irradiation: An in vitro study. Lasers Surg. Med. 2004. 35(4), 254-258.