Lagori G, Vescovi P, Merigo E, Meleti M, Fornaini C
Dental School, Faculty of Medicine, University of PARMA, Italy.
Laser Ther. 2014 Mar 27;23(1):21-30. doi: 10.5978/islsm.14-OR-03.
The purpose of this study was to evaluate the bleaching efficiency of two different lasers (KTP and diode 810 nm) on teeth, randomly divided by means an Excel function (Microsoft Excel 2010 "Fx causale") and stored in physiological solution, that were previously stained with different substances commonly considered as a cause of tooth discoloration, such as coffee, tea and red fruits and to investigate the role of laser irradiation in an experimental model, during the dental bleaching process.
Three groups of 45 bovine teeth were created and immersed for one week in a solution of tea, coffee or red fruits respectively. Each group was divided into three sub-groups of fifteen teeth. One was bleached with a 30% hydrogen peroxide gel for 30 min only as control, another 15 teeth group was bleached with the gel plus 810 nm diode laser irradiation and the last group was bleached with the gel plus KTP irradiation. The lasers were applied in three cycles of 30 sec each with a power of 1.5 W localized on a 10 mm spot on the teeth. The temperature of the gel was checked during the bleaching procedure using a thermometer and the colour of each tooth was measured by a spectrophotometer.
Statistical analysis of the collected data was performed using Graph Pad Prism, version 6.01 software, Kruskal-Wallis test and Dunn's multiple comparison test and Mann-Whitney test. P value <0.0001 was considered extremely significant (***), P value between 0.001 to 0.01 very significant (**), P value between 0.01 to 0.05 significant (*) and P value >0.05 not significant (ns). By these tests diode laser was effective only at bleaching teeth stained with coffee meanwhile the KTP laser was efficient at bleaching teeth with coffee, tea and red fruits stains.
This study suggests that a relation between the laser wavelength and the type of staining on the dental enamel and the efficacy of the whitening treatment exists.
本研究旨在评估两种不同激光（KTP激光和810nm二极管激光）对牙齿的漂白效果。牙齿通过Excel函数（Microsoft Excel 2010“Fx causale”）随机分组，并保存在生理溶液中，这些牙齿预先用通常被认为是牙齿变色原因的不同物质染色，如咖啡、茶和红色水果，同时研究激光照射在牙齿漂白过程的实验模型中的作用。
制备三组，每组45颗牛牙，分别在茶、咖啡或红色水果溶液中浸泡一周。每组再分为三个亚组，每组15颗牙。一组仅用30%过氧化氢凝胶漂白30分钟作为对照，另一组15颗牙用凝胶加810nm二极管激光照射进行漂白，最后一组用凝胶加KTP激光照射进行漂白。激光以1.5W的功率，每次30秒，分三个周期照射在牙齿上10mm的光斑区域。漂白过程中用温度计检查凝胶温度，用分光光度计测量每颗牙齿的颜色。
使用Graph Pad Prism 6.01软件、Kruskal-Wallis检验、Dunn多重比较检验和Mann-Whitney检验对收集的数据进行统计分析。P值<0.0001被认为极显著（***），P值在0.001至0.01之间为非常显著（**），P值在0.01至0.05之间为显著（*），P值>0.
