酪蛋白磷酸多肽-非结晶型磷酸钙对牙釉质抗酸蚀性能影响的原位研究

Effects of casein phosphopeptide-amorphic calcium phosphate on enamel erosion： an in situ study

目的建立牙侵蚀症的原位研究模型，探讨酸性饮料对牙釉质表面显微硬度（surface microhardness，SMH）的影响及酪蛋白磷酸多肽-非结晶型磷酸钙（casein phosphopeptide-amorphic calcium phosphate，CPP-ACP）对牙釉质抗酸蚀性能的影响。方法选择来自福建医科大学附属口腔医院口腔颌面外科门诊提供的因正畸需要而拔除的人恒前磨牙30颗，制备牙釉质．牙本质样本48个；募集12名福建医科大学在校大学生志愿者；用于两部分试验。验证性试验对2名健康志愿者（使用8个样本）制作可摘骀垫式牙托，每个牙托置入4个样本（2个样本牙釉质面对应牙托处开窗，2个不开窗）。指导志愿者配戴牙托并使用鼓漱法于5min内饮完150ml可乐，继续配戴牙托1h，完成1次酸蚀循环。每天连续进行4次酸蚀循环，连续7d。对照试验使用40个样本，用随机数字表法将样本随机分为两组（每组20个），CPP—ACP组样本牙釉质面用CPP-ACP处理，对照组样本牙釉质面用去离子水处理；对10名健康志愿者制作牙托，采用左右半口对照设计，每个牙托一侧开窗置入CPP-ACP组样本2个，另一侧开窗置入对照组样本2个，采用相同的原位酸蚀方案。使用显微硬度计及扫描电镜检测样本酸蚀前后的表面显微硬度及表面形貌变化。结果验证性试验显示，与酸蚀前相比，开窗样本酸蚀后SMH显著减小（P〈0．001）；与酸蚀后未开窗样本相比，开窗样本酸蚀后SMH显著减小（P〈0．001）。对照试验显示，CPP-ACP组酸蚀后SMH为（198．8±23．2）HV，对照组SMH为（152．4±42．1）HV，两组差异有统计学意义（P=0．040）。扫描电镜显示，CPP-ACP组样本牙釉质面酸蚀痕迹明显少于对照组。结论基于本项研究采用的原位研究模型，短时间饮用酸性饮料即可显著软化人牙釉质，使用CPP-ACP可提高牙釉质的抗酸蚀性能。

Objective To evaluate the effects of casein phosphopeptide-amorphic calcium phosphate （CPP-ACP） on enamel erosion using an improved in situ experimental protocol. Methods Forty-eight enamel blocks were prepared from fresh-extracted human premolars and further embedded in the acrylic resins. The present study was divided into 2 parts. In part 1 of the study, two volunteers were recruited to test the availability and safety of the in situ erosion protocol. Customized intraoral appliance was made with 4 reservoirs containing the specimens for each volunteer. For each intraoral applieanee, 2 reservoirs were made with the openings and the other 2 remained intact. All volunteers were instructed to drink 150 ml cola within 5 min using the gargling method after placing appliances intraorally for 2 h. After erosion, the appliances were remained undisturbed intraorally for 1 h until the next erosive attack. The in sita erosion cycles were performed 4 times daily over 7 d. In part 2 of the study, forty specimens were randomly divided into 2 groups （n=20）： CPP-ACP group and control group. The surfaces of specimens in CPP-ACP group were pretreated with CPP-ACP for 3 min before in situ erosion, whereas the specimens in control group were pretreated with deionized water for 3 min. For each intraoral applicance, 4 reservoirs were made with openings. Ten healthy volunteers were recruited and the above-mentioned in situ erosion protocol was applied to test the effects of CPP-ACP on enamel erosion. The surface microhardness and surface microstructure of the samples were examined before and after erosion in both parts of the study. The data were statistically analyzed using ANOVA and LSD tests. Data were considered statistically significant at a level of P〈0.05. Results Significant surface softening was observed in all specimens after erosion （P〈0.001）. The surface microhardness in the CPP-ACP group and control group were （198.8±23.2） and （152.4±42.1） HV, respectively （P=0.040）. The specimens in the CPP-ACP group showed significantly fewer changes in surface microstructure compared with those in the control group. Conclusions Based on this in situ experimental protocol, short-time consuming of acid beverages would produce significant effects on the surface microhardness of the human enamel, whereas the application of CPP-ACP can increase the erosion resistance of the enamel.