In vitro study on microleakage in class Ⅱ cavity restoration with different composite resins under three acid etching modes

WANG Xiao-ting; QIAO Zhi-xin; BAN Yue; XU Zhan-peng; LIU Li-hong; SHAO Li-na

doi:10.19538/j.kq.2025.04.006

Abstract：Objective Class Ⅱ cavities are prepared in vitro in extracted premolars to investigate the effects of three ac-id etching modes,namely etch-and-rinse(EAR),selec-tive-enamel etch(SEE),and self-etch(SE)on the micro-leakage of class Ⅱ cavity filled with five composite resins.Methods A total of 135 premolars extracted from pa-tients were selected,who visited the Department of Oral and Maxillofacial Surgery of the Affiliated Stomatological Hospital of China Medical University due to orthodontic treatment needs from June to August 2023.After preparing classⅡ cavities,they were randomly divided into three groups according to the acid etching mode:EAR group,SEE group,and SE group,with 45 teeth in each group.Each group was further randomly divided into five subgroups(9 teeth in each subgroup),and filled with 3M FiltekTM Z350 XT universal nanocomposite resin(Z350 subgroup)and four domestic com-posite resins[Dentex resin(Dentex subgroup),Antai biological resin(Antai biological subgroup),Zhangjiang biological resin(Zhangjiang biological subgroup),and Zhenghai biological resin(Zhenghai biological subgroup)].After thermocy-cling,the microleakage grades of each group were evaluated under a stereomicroscope using the dye penetration method,and the characteristics of the bonding interface were observed under a scanning electron microscope(SEM).The degree of microleakage was evaluated by calculating the volume of silver deposits through micro-computed tomography(Micro-CT)scanning.Results There was no statistically significant difference in the microleakage grades of the distal and gin-gival walls of class Ⅱ cavities filled with different composite resins using the same acid etching mode(P＞0.05).For the comparison of microleakage grades of class Ⅱ cavities filled with the same composite resin using different acid etching modes,there were statistically significant differences in the distal wall microleakage grades among the Z350 subgroup,Dentex subgroup,Antai biological subgroup,and Zhenghai biological subgroup(P＜0.05),while there were no statistical-ly significant differences in the gingival wall microleakage grades(P＞0.05).There were no statistically significant differ-ences in the distal and gingival wall microleakage grades of the Zhangjiang biological subgroup(all P＞0.05).Within the same composite resin subgroup of each acid etching mode group,the gingival wall microleakage grade was higher than that of the distal wall,and the differences were statistically significant(P＜0.001).Scanning electron microscopy obser-vations showed that the bonding interface of the distal and gingival walls of class Ⅱ cavities in the EAR group and the SEE group was relatively tight and straight,while in the SE group,the micro-cracks of bonding interface was wide,long,and irregular,with fragmentation.Micro-CT analysis results indicated that both the acid etching mode and the type of composite resin affected the volume of silver deposition,and there was an interaction effect between them(F values were 57.204,501.046,and 3.093,all P＜0.05).Within the same acid etching mode,the volume of silver deposition in the Zhangjiang biological subgroup was greater than that in the other subgroups;within the same resin type,the volume of sil-ver deposition in the SE group was greater than that in the EAR group and the SEE group,and the differences were statis-tically significant(P＜0.05).Conclusion Domestic composite resins(Dentex resin,Antai biological resin,and Zheng-hai biological resin)show similar marginal sealing properties to 3M Filtek™ Z350 XT universal nanocomposite resin when they are used for filling class Ⅱ cavities.The EAR mode and the SEE mode can reduce the microleakage degree compared with the SE mode.