Carvalho Erica dos Santos, Mello Isabel, Albergaria Silvio José, Habitante Sandra Márcia, Lage-Marques José Luiz, Raldi Denise Pontes
Department of Dentistry, University of Taubate, Taubate, São Paulo, Brazil.
Photomed Laser Surg. 2011 Aug;29(8):559-63. doi: 10.1089/pho.2010.2922. Epub 2011 Jun 1.
The disadvantage of photodynamic therapy (PDT) is in the photosensitizing agents that may stain the tooth structure. There is no register of PDT studies evaluating protocols to minimize that concern. The present study evaluated the efficiency of chemical adjuncts in methylene blue dye (MB) removal after PDT.
Forty single-rooted teeth, after root canal preparation, were filled with 0.01% MB for 5 min, and irradiated with diode laser 660 nm at 40 mW for 240 sec (total energy 9.6 J). The specimens were divided into four groups (n = 10), according to the chemical adjuncts used for dye removal: (a) 2.5% sodium hypochlorite (NaOCl); (b) 2.5% NaOCl + Endo-PTC cream; (c) 70% ethyl alcohol and (d) saline (control). The crowns were sectioned and fixed in a device. Photographs were taken before the PDT (T0), immediately after (T1) and upon dye removal (T2). The chromatic alterations were evaluated using Adobe Photoshop and K values were determined in four fixed points of each crown.
K values (dental staining) increased in all groups when comparing T0 and T1. The effectiveness of the tested adjuncts was, in decreasing order: G1 (-3.11) > G2 (-2.97) > G3 (-1.28) > G4 (-1.19), not observing significant statistical differences (p < 0.05) between G1 and G2 and also between G3 and G4.
Protocols to remove photosensitizing dyes should be applied after PDT in order to minimize dental stain. The protocols tested in this study by using 2.5% NaOCl, associated or not with Endo-PTC cream, were effective in avoiding tooth staining caused by MB during PDT.
光动力疗法（PDT）的缺点在于光敏剂可能会使牙齿结构染色。目前尚无评估可将该问题降至最低的方案的PDT研究记录。本研究评估了化学辅助剂在PDT后去除亚甲蓝染料（MB）的效果。
40颗单根牙在根管预备后，用0.01%的MB填充5分钟，然后用660nm二极管激光以40mW照射240秒（总能量9.6J）。根据用于去除染料的化学辅助剂，将标本分为四组（n = 10）：（a）2.5%次氯酸钠（NaOCl）；（b）2.5% NaOCl + Endo-PTC乳膏；（c）70%乙醇；（d）生理盐水（对照组）。将牙冠切开并固定在一个装置中。在PDT前（T0）、PDT后立即（T1）以及去除染料后（T2）拍照。使用Adobe Photoshop评估颜色变化，并在每个牙冠的四个固定点测定K值。
比较T0和T1时，所有组的K值（牙齿染色）均增加。所测试的辅助剂的有效性由高到低依次为：G1（-3.11）> G2（-2.97）> G3（-1.28）> G4（-1.19），G1和G2之间以及G3和G4之间未观察到显著统计学差异（p < 0.05）。
为了使牙齿染色最小化，应在PDT后应用去除光敏染料的方案。本研究中测试的使用2.5% NaOCl（有无Endo-PTC乳膏）的方案可有效避免PDT期间MB引起的牙齿染色。
