Abstract: Objective    To study the effect of amorphous calcium phosphate nanoparticles（NACP）and synthetic polypeptides（NH2-CQDSETRTFYDSHAKRHHGYKRKFHEKHHSHRGY-COOH，CYP）on microleakage at the edge of Class Ⅴ cavity backfill in isolated teeth. Methods    A total of 80 impacted molars extracted from patients treated in the Stomatology Department of the Affiliated Hospital of North Sichuan Medical College from April to June 2024 were collected，and Class Ⅴ cavities were prepared in the neck of the cheek and tongue side of the isolated teeth. All the isolated teeth were divided into total acid etching group and self-etching group with 40 teeth in each group（80 Class Ⅴ cavities）by random number table method. Then，according to the bonding and filling treatment method，they were divided into control subgroup（coated with general adhesive only），NACP subgroup（with mixed coating of general adhesive and 30% NACP by mass fraction），CYP subgroup（coated with general adhesive after 1% CYP treated cavity by mass fraction），and NACP+CYP subgroup（with mixed coating of general adhesive and 30% NACP by mass fraction after 1% CYP treated cavity by mass fraction）. There were 10 isolated teeth in each subgroup（20 Class Ⅴ cavities）. The isolated teeth were immersed in 2% methylene blue solution for 24 h after cyclic aging treatment，and the microleakage degree of occlusal wall and gingival wall of each group was observed and evaluated. Results    The microleakage scores of internal gingival wall in all subgroups were higher than those of occlusal wall，and the differences were statistically significant（all P < 0.05）. There were statistically significant differences in microleakage scores of occlusal wall and gingival wall between total acid etching group and self-etching group（all P < 0.05）. The microleakage scores of the occlusal wall and gingival wall of the NACP+CYP subgroups in the total and self-etching groups were lower than those in the control subgroup. The occlusal wall microleakage scores of NACP subgroup and CYP subgroup in total acid etching group were lower than those of control subgroup，and the gingival wall microleakage scores of NACP+CYP subgroup were lower than those of NACP subgroup，with statistical difference（all P < 0.05）. There were no significant differences in wall or gingival microleakage scores between each pair of groups with the same name between total and self-etching groups（P > 0.05）. Conclusion    Both NACP and CYP can reduce the degree of microleakage at the edge of Class Ⅴ cavity backfill to a certain extent，and the effect of combined application of both is better.

Key words: amorphous calcium phosphate nanoparticles, synthetic polypeptides, Class Ⅴ cavity, microleakage, adhesive, caries, remineralization

摘要： 目的    研究纳米无定型磷酸钙（amorphous calcium phosphate nanoparticles，NACP）与人工合成多肽（NH2-CQDSETRTFYDSHAKRHHGYKRKFHEKHHSHRGY-COOH肽，简称为“CYP”）对离体牙Ⅴ类洞充填体边缘微渗漏的影响。方法    收集2024年4—6月于川北医学院附属医院口腔科就诊患者拔除的阻生磨牙80颗，在离体牙颊、舌侧颈部制备Ⅴ类洞。采用随机数字表法将所有离体牙分为全酸蚀组和自酸蚀组，每组40颗（80个Ⅴ类洞）；再根据粘接-充填处理方法分为对照亚组（仅涂布通用型粘接剂）、NACP亚组（通用型粘接剂与质量分数为30%的NACP混合涂布）、CYP亚组（质量分数为1%的CYP处理窝洞后涂布通用型粘接剂）、NACP+CYP亚组（质量分数为1%的CYP处理窝洞后通用型粘接剂与质量分数为30%的NACP混合涂布），每亚组10颗离体牙（20个Ⅴ类洞）。冷热循环老化处理充填后的离体牙，浸泡于2%亚甲蓝溶液24 h，观察并评价各组壁和龈壁微渗漏程度。结果    各亚组内龈壁微渗漏评分均高于壁，差异均有统计学意义（均P < 0.05）。全酸蚀组和自酸蚀组各亚组壁、龈壁微渗漏评分比较，差异均有统计学意义（均P < 0.05）。其中，全酸蚀组和自酸蚀组中NACP+CYP亚组壁、龈壁微渗漏评分均低于对照亚组；全酸蚀组中NACP亚组、CYP亚组壁微渗漏评分均低于对照亚组，且NACP+CYP亚组龈壁微渗漏评分低于NACP亚组，差异均有统计学意义（均P < 0.05）。全酸蚀组与自酸蚀组相同名称亚组壁、龈壁微渗漏评分两两比较，差异均无统计学意义（均P > 0.05）。结论    NACP和CYP均可一定程度降低离体牙Ⅴ类洞充填体边缘微渗漏程度，且二者联合应用效果更佳。

关键词: 纳米无定型磷酸钙, 人工合成多肽, Ⅴ类洞, 微渗漏, 粘接剂, 龋病, 再矿化