目的: 比较不同浓度、不同着色方式的茶溶液着色离体牛切牙的效果及着色的持久性,探究茶溶液着色离体牙模型的最佳条件。方法: 选用牙冠唇面中1/3比色为A1色的牛切牙20颗,纵剖为40个样本,随机分为4组(n=10)。1组:2%(质量分数)茶溶液连续着色6 d;2组:2%茶溶液着色6 d,每日换液;3组:1%茶溶液连续着色6 d;4组:1%茶溶液着色6 d,每日换液。6 d后,经Crystaleye比色仪测量牙冠唇面中1/3的Lab值并计算ΔE值,选出着色效果最佳的浓度组,使用国际通用标准牙刷切龈向轻刷牙面30次,测量并计算ΔE值,选出着色效果最佳的换液方式组观察其稳定性,将样本浸泡于人工唾液中37 ℃保存14 d,每天测量并计算ΔE值,选出着色效果稳定的时间。结果: 着色6 d后,换液方式相同时,2%茶溶液着色效果优于1%组(20.21 vs. 16.44, 24.09 vs. 19.22, P<0.05);茶溶液浓度相同时,每天换液组优于不换液组(24.09 vs. 20.21, 19.22 vs. 16.44, P<0.05)。选1、2组进行刷牙实验,刷牙后两组颜色均变浅,且不换液组着色效果优于每天换液组(3.06 vs. 9.51, P<0.05)。选择着色效果最好的2%茶溶液连续浸泡6天组,放入人工唾液浸泡14 d,第1、2天牙面颜色无明显变化(1.51 vs. 1.51, P>0.05),第3天明显变浅(1.51 vs. 5.89, P<0.05), 至第14天颜色再无明显变化(5.89 vs. 5.81, P>0.05),且深于着色前。结论: 将离体牙在2%茶溶液连续着色6 d,然后将其保存在人工唾液中,第3~14天内着色效果稳定,可作为理想的离体牙着色模型。

Objective: To determine the optimum staining condition of tea solutions on bovine incisors in vitro, by comparing the color stability of tooth surface of different concentrations of tea solutions and methods on bovine incisors in vitro.Methods:Twenty bovine incisors with color surface A1 were chosen, then randomly divided into 4 groups (n=10). Group 1: soaked with 2% tea solution continuously for 6 days; group 2: soaked with 2% tea solution for 6 days, but changed fresh tea solution everyday; group 3: soaked with 1% tea solution continuously for 6 days; group 4: soaked with 1% tea solution for 6 days but fresh tea solution changed every day. After 6 days of staining, the surface color (ΔE value)of all the samples were measured with crystal eye. After brushing 30 times with toothbrushes, the color of bovine incisors were measured again. Then the samples were soaked in artificial saliva at 37 ℃, and ΔE value was measured for 14 days.Results:After staining for 6 days, the ΔE values of the 2% tea solution groups were better than those of the 1% groups (20.21 vs. 16.44, 24.09 vs. 19.22, P<0.05);the groups with the same tea solution concentration, a better result was observed for the group soaked with daily fresh tea solution than for the group that experienced continuous staining (24.09 vs. 20.21, 19.22 vs. 16.44, P<0.05).Groups 1 and 2 were selected for subsequent brushing experiments. The color of both groups became lighter after brushing, and a better result was observed for the continuous staining group than for the group stained in daily fresh solution (3.06 vs. 9.51, P<0.05). The samples with better coloring effect soaked with 2% tea solution continuously for 6 days were put into artificial saliva for 14 days. There was not any significant change in coloring at theend of the first two days (1.51 vs. 1.51, P>0.05), and the color was visibly lighter after the third day (1.51 vs. 5.89, P<0.05), and no further significant change was observed until the 14th day (5.81 vs.5.89, P>0.05), which was darker coloring than that of the pre-staining group.Conclusion:Continuous staining on bovine incisors with 2% tea solution with subsequent soaking in artificial saliva resulted in consistent coloring from day 3 to day 14, and this method could be used as an ideal model for teeth staining in vitro.