离体年轻恒牙脱矿后再矿化及美白效果的实验研究

Effect of Bleaching on Enamel Remineralization and Color Changes of Extracted Adolescent Teeth

目的探讨牙齿美白治疗对脱矿的离体年轻恒牙再矿化及牙色变化的作用。方法选取和制作24个离体的年轻恒牙标本,用微硬度测量仪(M-400-H1,St,Joseph,MI)测定牙体标本的硬度。牙体的颜色由ShadeVision(X-Rite,Inc.,Grand-ville,MI)来测定。脱矿处理后,选取的每个标本的牙体硬度控制在170KHN(努氏硬度)左右。24个标本被随机地分成A、B、C3组(P>0.05),每组8个标本。C组用美白产品Treswhite进行7次漂白治疗,同时A、B组标本浸泡于人唾液中。然后B、C组用含氟的Crest牙膏进行再矿化处理,而A组用无氟的Crest牙膏进行再矿化处理。每个牙标本的硬度(KHN)和颜色(CIELAB)的数据分别在以下4个阶段采集:原始阶段(BL)、脱矿后(AL)、美白治疗或唾液浸泡后(AB/S)、和矿化治疗后(AR)。结果3组标本的牙硬度在BL、AL和AB/S阶段不存在显著的差异(P>0.05),在AR阶段,B组、C组标本牙硬度增高而A组牙硬度下降(P<0.001)。脱矿后阶段(AD)各组的牙颜色变化CIELAB数据ΔE接近8,在AB/S阶段与AD阶段之间,C组的ΔE值明显高于A、B组(P=0.001),经过再矿化处理,各阶段之间的ΔE值变小及每组间的ΔE值不存在显著的差异。结论美白产品Tre-swhite对脱矿的离体年轻恒牙的再矿化无不良反应,而对其牙颜色的变化无明显的影响。

Objective To investigate the effect of bleaching management on enamel remineralization potential and color of extracted adolescent permanent teeth. Methods Twenty- four enamel specimens prepared from extracted adolescent permanent teeth were measured for Knoop Hardness Number （KHN） with a Leco Microhardness Tester （M -400 -H1, St, Joseph, MI）. The color was determined using the Shade Vision （X - Rite, Inc, , Grandville, MI）, The specimens were determineralized to achieve the KHN around 170 and they were then randomly assigned to Group A, B, or C （8/group）. Group C received bleaching treatments for seven times with treswhite by Opalescence （Ultradent Products, South Jordan, UT） following manufacturer instruction; Group A and B were treated with pooled human saliva. Group B and C were then treated by a fluoride dentifrice （Crest Regular, Procter and Gamble,Cincinnati, OH） , while Group A was treated by a non - fluoride dentifrice, all in cycles of acid challenge and dentifrice treatment, The KHN and color data （CIELAB） were collected at the baseline （BL） , after - demineralization （AD） , after - bleaching or saliva treatment （AB/S） , and after - remineral- ization （AR）. The data were analyzed using the One - way ANOVA and Student - newman - Keuls methods, Results There were no significant differences in the KHN values among the three groups at the BL, AL and AB/S, However, after remineralization the KHN increased in Groups B and C but decreased in Group A ; the microhardness for Groups B and C were significantly higher （ P 〈 0. 001 ） thanthat of Group A, indicating no adverse effect of bleaching on enamel remineralization. The CIELAB data showed a color change of approximately 8 Delta E after demineralization. Bleaching treatment resulted in a significantly higher Delta E, while the remineralization process reduced the differences in Delta E among the groups. Conclusion Bleaching treatment with treswhite by Opalescence does not adversely affect the remineralization and color change potential of the demineralized enamel of adolescent permanent teeth.