Objective A study was conducted to compare the effect of different enamel remineralization periods after erosion on the depth of brushing abrasion. Methods Ten volunteers were selected for a 4-day experiment. A total of 60 enamels were randomly assigned into six groups (A-F) and placed in intraoral palatal devices. On the first day, the palatal devices were placed in oral cavity (24 h) . On the following three days, brushing experiments were performed extraorally, two times per day. The specific experimental method of brushing follows these next steps. First, the group F specimens were covered with a film of wax, and then acid etched for 2 min. Subsequently, the film of wax was detached. The groups from A to D were brushed after remineralization at the following time intervals: group A, 0 min; group B, 20 min; group C, 40 min; group D, 60 min. Erosion and remineralization were performed on group E, but without brushing. Remineralization was performed on group F, but without acid etching and brushing. The depth of enamel abrasion was determined by a mechanical profilometer. The surface morphology of the enamel blocks was observed using a scanning electron microscope. Results 1) The depth of abrasion was different in varied enamel remineralization time after acid etching. The statistical significant differences between groups were as follows. 2) When the time of enamel remineralization after acid etching was short, the surface depression in the electron microscope was deep, and the surface morphology was rough. Conclusion Brushing immediately after acid etching would cause much serious abrasion to the enamel surface. Brushing after 60 min can effectively reduce the abrasion of acid etching enamel.
目的 比较经柠檬酸酸蚀后的釉质块在不同再矿化时间后，刷牙对其表面磨损深度的影响。方法 60个釉质块平均分为A~F共6组，分别安置在10个志愿者的腭基托上。实验第1天，志愿者口腔中佩戴腭基托24 h，其后3 d，每天进行刷牙实验2次。步骤如下：首先，用蜂蜡覆盖F组釉质块，将腭基托置于50 mL柠檬酸溶液中酸蚀2 min，然后取出腭基托，冲洗，并将F组釉质块蜂蜡去除；其他组为酸蚀后经过不同的再矿化时间后刷牙（A组：0 min；B组：20 min；C组：40 min；D组：60 min；E组：酸蚀并且再矿化，但不刷牙；F组：不酸蚀，再矿化，刷牙）。进食及清洁时取出腭基托，其余时间均需佩戴腭基托。通过表面轮廓仪测量釉质块的磨损深度，并用扫描电子显微镜（SEM）观察其表面形貌。结果 酸蚀后经过不同时间的再矿化，刷牙对釉质块表面造成的磨损深度不同，各组间的差异具有统计学意义（P<0.05）。SEM结果显示，釉质酸蚀后再矿化时间越短，刷牙后表面凹陷越大越深越多，表面形态越粗糙。结论 釉质被酸蚀后，在唾液中再矿化时间增加，立即刷牙会对釉质表面形成较大的磨损，60 min后再刷牙可以有效减少刷牙对酸蚀釉质的磨损。.
Keywords: acid etching; brushing wear; fluoride toothpaste; remineralization.