Abstract: Objective    To explore the effect of artificial saliva on residual white spots after infiltration resin treatment and analyze the sagittal surface morphology of residual white spots on tooth enamel surface. Methods    A total of 45 premolars for reduction extraction due to orthodontic treatment were selected from the surgical clinic of Stomatology Hospital of Tianjin Medical University from April to May 2022，as well as the third molars that were impacted by an embedment and could not be retained. There were still a few white spots on the surface of the isolated teeth after demineralization by infiltration resin treatment. Five isolated teeth were randomly selected without any treatment（control group），and the remaining isolated teeth were randomly divided into distilled water group（soaked in distilled water for 3 months）and artificial saliva group（soaked in artificial saliva for 3 months），with 20 teeth in each group. The residual white spot on the enamel surface of the distilled water group and the artificial saliva group were photographed by a digital camera，and the color difference（ΔE）values after 1 and 3 months of immersion were measured and calculated by Adobe Photoshop 2020 image analysis software，which were denoted as ΔE1 and ΔE2，respectively. The morphology of sagittal surface of white spot on the enamel surface of the control group，the distilled water group and the artificial saliva group after 1 and 3 months were observed by scanning electron microscope. Results    ΔE1 ［2.54（1.98，2.88）］ and ΔE2 ［5.06（4.02，6.90）］ in artificial saliva group were higher than ΔE1 ［1.37（1.18，2.27）］ and ΔE2 ［3.18（2.09，4.06）］ in distilled water group. The differences were statistically significant（Z values were -2.725 and -3.177，respectively，P < 0.05）. In comparison within the artificial saliva group and the distilled water group，ΔE2 was greater than ΔE1，and the differences were statistically significant（Z values were -3.782 and -2.496，respectively，P < 0.05）. Scanning electron microscope（SEM）showed that there were more pores between the sagittal penetrating resin and the enamel column in the control group，and no pores between the sagittal penetrating resin and the enamel column in the control group without white spots. In the distilled water group，there were many pore structures in the cut sagittal surface of residual white spots. In the artificial saliva group，there were fewer sagittal pore structures in the residual white spots，and there were even fewer after 3 months than after 1 month. Conclusion    Artificial saliva can reduce the chalkiness of the residual white spots on the enamel surface after infiltration resin treatment. The appearance of residual white spots may be related to the pores between the infiltration resin and the enamel column.

Key words: infiltration resin, remineralization, residual white spot, color difference

摘要： 目的    探究渗透树脂治疗后人工唾液对残留白斑的作用效果并分析牙釉质表面残留白斑的矢状面形貌。方法    选取2022年4—5月于天津医科大学口腔医院外科门诊部因正畸治疗需减数拔除的前磨牙及埋伏阻生无法保留的第三磨牙45颗，脱矿后的离体牙经渗透树脂处理后表面仍有少量白斑。随机选取5颗离体牙不做任何处理（对照组），剩余的离体牙随机分为蒸馏水组（使用蒸馏水浸泡3个月）和人工唾液组（使用人工唾液浸泡3个月），每组20颗。单反数码相机拍照蒸馏水组和人工唾液组牙釉质表面残留白斑，并应用Adobe Photoshop 2020图像分析软件测量并计算浸泡1、3个月后的色差（ΔE）值，分别记为ΔE1和ΔE2；扫描电镜观察对照组及浸泡1、3个月后的蒸馏水组与人工唾液组牙釉质表面白斑切割矢状面形貌。结果    人工唾液组ΔE1 ［ 2.54（1.98，2.88）］和ΔE2 ［ 5.06（4.02，6.90）］分别大于蒸馏水组的ΔE1 ［ 1.37（1.18，2.27）］和ΔE2 ［ 3.18（2.09，4.06）］，差异均有统计学意义（Z值分别为-2.725、-3.177，均P < 0.05）；人工唾液组和蒸馏水组的组内比较，ΔE2均大于ΔE1，差异均有统计学意义（Z值分别为-3.782、-2.496，均P < 0.05）。扫描电镜观察发现，对照组残留白斑处切割矢状面渗透树脂与釉柱间可见较多孔隙，无白斑处切割矢状面渗透树脂与釉柱间无孔隙；蒸馏水组残留白斑处切割矢状面孔隙状结构均较多；人工唾液组残留白斑处切割矢状面孔隙状结构均较少，且浸泡3个月后较浸泡1个月后更少。结论 人工唾液能使经渗透树脂治疗后牙釉质表面残留白斑的白垩色程度减弱，残留白斑的出现可能与渗透树脂和釉柱间的孔隙有关。

关键词: 渗透树脂, 再矿化, 残留白斑, 色差值